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Sample search results for: palapa b2r satellite

 

1

Modeling And Simulation Of Prolate Dual-Spin Satellite Dynamics In An Inclined Elliptical Orbit: Case Study Of Palapa B2R Satellite

  CERN Preprints

Summary: In response to the interest to re-use Palapa B2R satellite nearing its End of Life (EOL) time, an idea to incline the satellite orbit in order to cover a new region has emerged in the recent years. As a prolate dual-spin vehicle, Palapa B2R has to be stabilized against its internal energy dissipation effect. This work is focused on analyzing the dynamics of the reusable satellite in its inclined orbit. The study discusses in particular the stability of the prolate dual-spin satellite under the effect of perturbed field of gravitation due to the inclination of its elliptical orbit. Palapa B2R physical data was substituted into the dual-spin's equation of motion. The coefficient of zonal harmonics J2 was induced into the gravity-gradient moment term that affects the satellite attitude. The satellite's motion and attitude were then simulated in the perturbed gravitational field by J2, with the variation of orbit's eccentricity and inclination. The analysis of the satellite dynamics and its stability was conducte...

Muliadi, J; Budiyono, A
2008-01-01

2

Solutions to Home-work 11 1. (a) Notice that if B2(R3) and x, y R3 are arbitrary, and

  Mathematics Websites

Summary: define ij = (ei, ej), then (x, y) = (x, 3 j=1 ej (y)ej) = 3 j=1 ej (y)(x, ej) = 3 j=1 ej (y)( 3 i=1 ei (x)ei, ej) = 3 i=1 3 j=1 ei (x)ej (y)(ei, ej) = 3 i=1 3 j=1 (ei, ej)ei ej (x, y) , thereby showing that {ei ej : 1 i, j 3} is a spanning set for B2(R3). The above string of equations can also be used

Sunder, V S

3

satellite imagery.

  CiteSeer

Summary: Air traffic is still closed in many European countries. The VAAC bulletin still maintains the Red alert for the next 12 hours. Ash prediction seems to reduce slightly but the direction of the source is directed towards south in the forecast of tomorrow 18/4/2010 00:00 The satellite image below shows the ash plume as of 16 April 2010, as seen from MODIS optical

unknown authors

4

EUROPE'S GEOSTATIONARY METEOROLOGICAL SATELLITES

  Geosciences Websites

Summary: METEOSAT EUROPE'S GEOSTATIONARY METEOROLOGICAL SATELLITES MONITORING WEATHER AND CLIMATE FROM SPACE, 6 July 2010 Paul de Valk Koninklijk nederlands Meteorologisch instituut (KnMi) "you need satellites for a country to have its own satellites so it is very beneficial to share costs in Europe, as we do through Eu

Stoffelen, Ad

5

Equalizers for communications satellites

  MIT - DSpace

Summary: This thesis investigates equalization for advanced protected satellite communications systems in development at MIT Lincoln Laboratory. Equalizers facilitate high data rate communication by correcting dispersion in the ...

Fay, Leon
2008-01-01

6

Correspondence Satellites: make data

  Biology and Medicine Websites

Summary: all the data free to access online. Data from NASA's MODIS and all of their Earth-observation imagery are also available for free, as are data from the China­ Brazil Earth Resources Satellite programme. Woody Turner* Earth Science Division, NASA, Washington DC, USA. Satellites: ambition for forest initiative We

Courchamp, Franck

7

Experimental Satellite Quantum Communications

  Quantum Physics (arXiv)

Summary: Quantum Communications on planetary scale require complementary channels including ground and satellite links. The former have progressed up to commercial stage using fiber-cables, while for satellite links, the absence of terminals in orbit has impaired theirs development. However, the demonstration of the feasibility of such links is crucial for designing space payloads and to eventually enable the realization of protocols such as quantum-key-distribution (QKD) and quantum teleportation along satellite-to-ground or intersatellite links. We demonstrated the faithful transmission of qubits from space to ground by exploiting satellite corner cube retroreflectors acting as transmitter in orbit, obtaining a low error rate suitable for QKD. We also propose a two-way QKD protocol exploiting modulated retroreflectors that necessitates a minimal payload on satellite, thus facilitating the expansion of Space Quantum Communications.

Giuseppe Vallone; Davide Bacco; Daniele Dequal; Simone Gaiarin; Vincenza Luceri; Giuseppe Bianco; Paolo Villoresi
2014-06-16

8

SPRING 2013 SATELLITE TUTORING CENTERS

  Biology and Medicine Websites

Summary: SPRING 2013 SATELLITE TUTORING CENTERS Satellite Tutoring Centers will not operate on the following dates: Monday, 1/21/13 Sunday, 3/3/13 -- Sunday, 3/10/13 Satellite Tutoring Center services end Tuesday

Plotkin, Joshua B.

9

Optimization of Satellite Constellation Reconfiguration

  Engineering Websites

Summary: Optimization of Satellite Constellation Reconfiguration by Uriel Scialom Submitted Students #12;2 #12;Optimization of Satellite Constellation Reconfiguration by Uriel Scialom Submitted for the degree of Master of Science in Aeronautics and Astronautics Abstract Traditional satellite constellation


10

On satellites in arbitrary categories

  CERN Preprints

Summary: We generalize the definition of satellites with respect to presheaves (and copresheaves) with trace in the sense of Inassaridze; a presheaf with trace is replaced by a graph with a pair of diagrams defined on it. We show that the right satellite functor is left adjoint to the left satellite functor, and that a functor having a right (left) adjoint preserves right (left) satellites. In particular cases the construction of satellites is given.

Janelidze, George
2008-01-01

11

Satellite Products and Services Review Board ATBD: Satellite-Derived

  Environmental Sciences and Ecology Websites

Summary: Satellite Products and Services Review Board ATBD: Satellite-Derived Ocean Heat Content Version 1.0 July 2012 ___________________________________ #12;NOAA /RSMAS ATBD : Satellite-Derived Ocean Heat Content Product Page 2 of 32 TITLE: ALGORITHM THEORETICAL BASIS DOCUMENT FOR OCEAN HEAT CONTENT VERSION 1

Miami, University of

12

SATELLITE METEOROLOGY Guosheng Liu

  Geosciences Websites

Summary: , USA Key Words: absorption, brightness temperature, radiometer, radiative transfer equation, remote sensing, scattering, sounding channel, window channel. Contents 1. Introduction 2. Principles of Satellite.2.1 Surface Temperature Retrieval 2.2.2 Atmospheric Sounding 2.3 Microwave Radiation under Cloudy Sky 2

Wang, Yuqing

13

Dynamical friction on satellite galaxies

  Astrophysics (arXiv)

Summary: For a rigid model satellite, Chandrasekhar's dynamical friction formula describes the orbital evolution quite accurately, when the Coulomb logarithm is chosen appropriately. However, it is not known if the orbital evolution of a real satellite with the internal degree of freedom can be described by the dynamical friction formula. We performed N-body simulation of the orbital evolution of a self-consistent satellite galaxy within a self-consistent parent galaxy. We found that the orbital decay of the simulated satellite is significantly faster than the estimate from the dynamical friction formula. The main cause of this discrepancy is that the stars stripped out of the satellite are still close to the satellite, and increase the drag force on the satellite through two mechanisms. One is the direct drag force from particles in the trailing tidal arm, a non-axisymmetric force that slows the satellite down. The other is the indirect effect that is caused by the particles remaining close to the satellite after escape. The force from them enhances the wake caused in the parent galaxy by dynamical friction, and this larger wake in turn slows the satellite down more than expected from the contribution of its bound mass. We found these two have comparable effects, and the combined effect can be as large as 20% of the total drag force on the satellite.

Michiko Fujii; Yoko Funato; Junichiro Makino
2006-06-23

14

REZA RABIEI, PhD 2444 Benny Crescent ~ Montreal, Quebec H4B 2R3

  Engineering Websites

Summary: . Best Paper by a Young Researcher, awarded at the 12th International Congress on Fracture (July 12. Rabiei. Ranked 150th in Nation-Wide Entrance Examination for Graduate Studies in Applied & Solid. Ranked 468th in Nation-Wide Entrance Examination for Undergraduate Studies in Physics & Mathematics among

Barthelat, Francois

15

What determines satellite galaxy disruption?

  CERN Preprints

Summary: In hierarchical structure formation, dark matter halos that merge with larger halos can persist as subhalos. These subhalos are likely hosts of visible galaxies. While the dense halo environment rapidly strips subhalos of their dark mass, the compact luminous material can remain intact for some time, making the correspondence of galaxies with severely stripped subhalos unclear. Many galaxy evolution models assume that satellite galaxies eventually merge with their central galaxy, but this ignores the possibility of satellite tidal disruption. We use a high-resolution N-body simulation of cosmological volume to explore satellite galaxy merging/disruption criteria based on dark matter subhalo dynamics. We explore the impact that satellite merging/disruption has on the Halo Occupation Distribution, radial profile, satellite fraction, and spatial clustering of the remnants. We compare with observed satellite fractions and galaxy clustering, using abundance matching to assign stellar masses to subhalos, finding th...

Wetzel, Andrew R
2009-01-01

16

Interferometric Observations of Geosynchronous Satellites

  CERN Preprints

Summary: In recent years, a large number of geosynchronous satellites are being planned to provide augmentation services for enhancing the precision to global positioning systems, e.g., GPS, in applications such as aircraft landing. In this paper, we present a scheme for co-locating passive satellite observational facilities with a radio astronomy facility to open a new possibility of providing valuable data for radio astronomical imaging, ionospheric studies and satellite orbit estimation.

Subrahmanya, C R; Somashekar, R
2011-01-01

17

Satellite Radio: Its Global Impact

  Biology and Medicine Websites

Summary: Spectrum L-band S-band Audio Compression MPEG AAC+ RF Design Propagation Models TDM, MCM, OFDM Examples WorldSpace XM Sirius MBSAT #12;8 Satellite Radio: A Confluence of Technologies Radio Radio Internet;10 LOS to Satellite Repeater Coverage Region 1 2 3 elv Terrestrial MCM Single Frequency Network Radiated

Udgaonkar, Jayant B.

18

2, 135, 2005 Satellite observations

  Physics Websites

Summary: -year satellite observations of instability waves in the Tropical Atlantic Ocean A. C. V. Caltabiano1 , I. SOSD 2, 1­35, 2005 Satellite observations of TIW in the Atlantic Ocean A. C. V. Caltabiano et al Print Version Interactive Discussion EGU Ocean Science Discussions, 2, 1­35, 2005 www.ocean

Paris-Sud XI, Université de

19

Anisotropic Locations of Satellite Galaxies

  CERN Preprints

Summary: The locations of the satellites of isolated host galaxies in the Sloan Digital Sky Survey (SDSS) and the Millennium Run simulation are investigated. On average, satellites are found near the major axes of their hosts, and the degree of anisotropy is a strong function of color and of the redshift at which satellites first enter their hosts' halos. In contrast to previous studies, we find the degree of anisotropy to be a strong function of the host mass. Further, when the satellite locations are averaged over radii r_p 300 kpc the satellites of blue SDSS hosts are found close to their hosts' minor axes (i.e., the Holmberg effect). This may indicate a systematic misalignment of the angular momentum vectors of disk galaxies and the n et angular momentum of their halos.

Agustsson, Ingolfur
2007-01-01

20

Redefining the Missing Satellites Problem

  Astrophysics (arXiv)

Summary: Numerical simulations of Milky-Way size Cold Dark Matter (CDM) halos predict a steeply rising mass function of small dark matter subhalos and a substructure count that greatly outnumbers the observed satellites of the Milky Way. Several proposed explanations exist, but detailed comparison between theory and observation in terms of the maximum circular velocity (Vmax) of the subhalos is hampered by the fact that Vmax for satellite halos is poorly constrained. We present comprehensive mass models for the well-known Milky Way dwarf satellites, and derive likelihood functions to show that their masses within 0.6 kpc (M_0.6) are strongly constrained by the present data. We show that the M_0.6 mass function of luminous satellite halos is flat between ~ 10^7 and 10^8 M_\\odot. We use the ``Via Lactea'' N-body simulation to show that the M_0.6 mass function of CDM subhalos is steeply rising over this range. We rule out the hypothesis that the 11 well-known satellites of the Milky Way are hosted by the 11 most massive subhalos. We show that models where the brightest satellites correspond to the earliest forming subhalos or the most massive accreted objects both reproduce the observed mass function. A similar analysis with the newly-discovered dwarf satellites will further test these scenarios and provide powerful constraints on the CDM small-scale power spectrum and warm dark matter models.

Louis E. Strigari; James S. Bullock; Manoj Kaplinghat; Juerg Diemand; Michael Kuhlen; Piero Madau
2007-10-24

21

The tidal stripping of satellites

  Astrophysics (arXiv)

Summary: We present an improved analytic calculation for the tidal radius of satellites and test our results against N-body simulations. The tidal radius in general depends upon four factors: the potential of the host galaxy, the potential of the satellite, the orbit of the satellite and {\\it the orbit of the star within the satellite}. We demonstrate that this last point is critical and suggest using {\\it three tidal radii} to cover the range of orbits of stars within the satellite. In this way we show explicitly that prograde star orbits will be more easily stripped than radial orbits; while radial orbits are more easily stripped than retrograde ones. This result has previously been established by several authors numerically, but can now be understood analytically. For point mass, power-law (which includes the isothermal sphere), and a restricted class of split power law potentials our solution is fully analytic. For more general potentials, we provide an equation which may be rapidly solved numerically. Over short times ($\\simlt 1-2$ Gyrs $\\sim 1$ satellite orbit), we find excellent agreement between our analytic and numerical models. Over longer times, star orbits within the satellite are transformed by the tidal field of the host galaxy. In a Hubble time, this causes a convergence of the three limiting tidal radii towards the prograde stripping radius. Beyond the prograde stripping radius, the velocity dispersion will be tangentially anisotropic.

J. I. Read; M. I. Wilkinson; N. W. Evans; G. Gilmore; Jan T. Kleyna
2005-11-15

22

NEWS Satellite Fragmentations in 1996

  CiteSeer

Summary: The year 1996 witnessed four significant satellite fragmentations, including the first recorded natural collision between two cataloged objects and the worst official satellite breakup in terms of cataloged debris. In addition, a number of anomalous events occurred with most related to classes of satellites known for such behavior. On 19 February, the Russian Proton Block DM being used to carry the Raduga 33 spacecraft apparently brokeup into at least 200 objects near its first GTO apogee. Although no debris were cataloged, six to nine debris have routinely been in track by the US Space Surveillance Network during most of the year. The breakup of the STEP II Pegasus/HAPS upper

Robert C. Reynolds; Cindi A. Karpiuk; Nicholas Johnson
1997-01-01

23

Shape Alignments of Satellite Galaxies

  Astrophysics (arXiv)

Summary: We test a sample of satellites of isolated primary galaxies, extracted from the 2dF Galaxy Redshift Survey (2dFGRS), for any tendency to be aligned along (or against) the primary-to-satellite radius vector. If tidal effects induce such an alignment, it would contaminate recent measurements of galaxy halo masses which use the coherent alignment induced on background galaxies by gravitational lensing. The mean tangential ellipticity of 1819 satellites within 500 kpc projected radius is = +0.004+-0.008, so no tidal alignment is detected. This implies at 95% confidence that satellite alignment is less than a 20% contamination of the alignment signal attributed to galaxy-galaxy lensing by Smith et al. (2001) and McKay et al. (2001).

G. M. Bernstein; P. Norberg
2002-05-29

24

MAE Seminar Series Satellite Formations

  Engineering Websites

Summary: -satellite fuel balancing using continuous as well as a two-impulse-per-orbit scheme will be presented. An example easy solutions which can be obtained from the basics. Bio Dr. Vadali has been a member of the faculty

Krovi, Venkat

25

Biogeography based Satellite Image Classification

  CERN Preprints

Summary: Biogeography is the study of the geographical distribution of biological organisms. The mindset of the engineer is that we can learn from nature. Biogeography Based Optimization is a burgeoning nature inspired technique to find the optimal solution of the problem. Satellite image classification is an important task because it is the only way we can know about the land cover map of inaccessible areas. Though satellite images have been classified in past by using various techniques, the researchers are always finding alternative strategies for satellite image classification so that they may be prepared to select the most appropriate technique for the feature extraction task in hand. This paper is focused on classification of the satellite image of a particular land cover using the theory of Biogeography based Optimization. The original BBO algorithm does not have the inbuilt property of clustering which is required during image classification. Hence modifications have been proposed to the original algorithm and...

Panchal, V K; Kaur, Navdeep; Kundra, Harish
2009-01-01

26

Satellites of Isolated Elliptical Galaxies

  Astrophysics (arXiv)

Summary: Using well-defined selection criteria applied to the LEDA galaxy catalogue we have derived a sample of elliptical galaxies that can be classified as isolated. From this we have investigated the neighbourhood of these galaxies to determine the frequency and radial distribution of faint galaxies around them and hence derive an estimate of their surrounding satellite population. The results are compared and contrasted to the satellite population around isolated spiral galaxies.

Rodney M. Smith; Vicent J. Martinez
2003-09-30

27

Want to Install A Satellite Dish ?

  Environmental Sciences and Ecology Websites

Summary: Want to Install A Satellite Dish ? Good News! Satellite dishes are allowed in Family & Graduate of units to allow for installation of satellite dishes are not permitted. If damage oc- curs to Family damage to satellite dish equipment. 3. Residents are expected to maintain the grounds/area surrounding

Maxwell, Bruce D.

28

Realizing Future Broadband Satellite Network Services

  Computer Technologies and Information Sciences Websites

Summary: @cis.ohio-state.edu ABSTRACT Future satellite communication systems proposed use geosynchronous (GEO) satellites, medium earth challenges before telecommunications industry in the 21st century. Satellite communication networks canRealizing Future Broadband Satellite Network Services Sastri Kota Arjan Durresi, Raj Jain Lockheed

Jain, Raj

29

More Satellites of Spiral Galaxies

  Astrophysics (arXiv)

Summary: We present a revised and expanded catalog of satellite galaxies of a set of isolated spiral galaxies similar in luminosity to the Milky Way. This sample of 115 satellites, 69 of which were discovered in our multifiber redshift survey, is used to further probe the results obtained from the original sample (Zaritsky et al. 1993). The satellites are, by definition, at projected separations <~ 500 kpc, have absolute recessional velocity differences with respect to the parent spiral of less than 500 km/s and are at least 2.2 mag fainter than their associated primary galaxy. A key characteristic of this survey is the strict isolation of these systems, which simplifies any dynamical analysis. We find no evidence for a decrease in the velocity dispersion of the satellite system as a function of radius out to galactocentric radii of 400 kpc, suggesting that the halo extends well beyond 200 kpc. Furthermore, the new sample affirms our previous conclusions (Zaritsky et al. 1993) that (1) the velocity difference between a satellite and its primary is not strongly correlated with the rotation speed of the primary, (2) the system of satellites has a slight net rotation (34 \\pm 14 km\\s) in the same sense as the primary's disk, and (3) that the halo mass of an ~ L* spiral galaxy is in excess of 2 x 10^{12} solar masses.

Dennis Zaritsky; Rodney Smith; Carlos Frenk; Simon D. M. White
1996-11-24

30

Satellite Luminosities in Galaxy Groups

  Astrophysics (arXiv)

Summary: Halo model interpretations of the luminosity dependence of galaxy clustering assume that there is a central galaxy in every sufficiently massive halo, and that this central galaxy is very different from all the others in the halo. The halo model decomposition makes the remarkable prediction that the mean luminosity of the non-central galaxies in a halo should be almost independent of halo mass: the predicted increase is about 20% while the halo mass increases by a factor of more than 20. In contrast, the luminosity of the central object is predicted to increase approximately linearly with halo mass at low to intermediate masses, and logarithmically at high masses. We show that this weak, almost non-existent mass-dependence of the satellites is in excellent agreement with the satellite population in group catalogs constructed by two different collaborations. This is remarkable, because the halo model prediction was made without ever identifying groups and clusters. The halo model also predicts that the number of satellites in a halo is drawn from a Poisson distribution with mean which depends on halo mass. This, combined with the weak dependence of satellite luminosity on halo mass, suggests that the Scott effect, such that the luminosities of very bright galaxies are merely the statistically extreme values of a general luminosity distribution, may better apply to the most luminous satellite galaxy in a halo than to BCGs. If galaxies are identified with halo substructure at the present time, then central galaxies should be about 4 times more massive than satellite galaxies of the same luminosity, whereas the differences between the stellar M/L ratios should be smaller. Therefore, a comparison of the weak lensing signal from central and satellite galaxies should provide useful constraints. [abridged

Ramin A. Skibba; Ravi K. Sheth; Matthew C. Martino
2008-05-05

31

Gaussian Entanglement Distribution via Satellite

  CERN Preprints

Summary: In this work we analyse three quantum communication schemes for the generation of Gaussian entanglement between two ground stations. Communication occurs via a satellite over two independent atmospheric fading channels dominated by turbulence-induced beam wander. In our first scheme the engineering complexity remains largely on the ground transceivers, with the satellite acting simply as a reflector. Although the channel state information of the two atmospheric channels remains unknown in this scheme, the Gaussian entanglement generation between the ground stations can still be determined. On the ground, distillation and Gaussification procedures can be applied, leading to a refined Gaussian entanglement generation rate between the ground stations. We compare the rates produced by this first scheme with two competing schemes in which quantum complexity is added to the satellite, thereby illustrating the trade-off between space-based engineering complexity and the rate of ground-station entanglement generation...

Hosseinidehaj, Nedasadat
2014-01-01

32

Chameleon gravity and satellite geodesy

  CERN Preprints

Summary: We consider the possibility of the detection of a chameleon effect by an earth orbiting satellite such as LAGEOS, and possible constraints that might be placed on chameleon model parameters. Approximate constraints presented here result from using a simple monopole approximation for the gravitational field of the earth, along with results from the Khoury-Weltman chameleon model, solar system constraints obtained from the Cassini mission, and parameter bounds obtained from the LAGEOS satellite. It is furthermore suggested that a comparison of ground-based and space-based multipole moments of the geopotential could reveal a possible chameleon effect.

Morris, J R
2014-01-01

33

More Satellites of Spiral Galaxies

  CERN Preprints

Summary: We present a revised and expanded catalog of satellite galaxies of a set of isolated spiral galaxies similar in luminosity to the Milky Way. This sample of 115 satellites, 69 of which were discovered in our multifiber redshift survey, is used to further probe the results obtained from the original sample (Zaritsky et al. 1993). The satellites are, by definition, at projected separations <~ 500 kpc, have absolute recessional velocity differences with respect to the parent spiral of less than 500 km/s and are at least 2.2 mag fainter than their associated primary galaxy. A key characteristic of this survey is the strict isolation of these systems, which simplifies any dynamical analysis. We find no evidence for a decrease in the velocity dispersion of the satellite system as a function of radius out to galactocentric radii of 400 kpc, suggesting that the halo extends well beyond 200 kpc. Furthermore, the new sample affirms our previous conclusions (Zaritsky et al. 1993) that (1) the velocity difference betwe...

Zaritsky, D; Frenk, C S; White, S D M; Zaritsky, Dennis; Smith, Rodney; Frenk, Carlos; White, Simon D.M.
1996-01-01

34

Monitoring Malaria from Operational Satellites

  Geosciences Websites

Summary: and Environment · AVHRR Sensor & Data · Vegetation Health (VH) System · Data Applications & Interpretation 78 89 African trypanosomiasis 3 3 Lymphatic filariasis 10 0 Dengue fever 1 2 Leishmamiasis 5 5 Chaga conditions MOISTURE THERMAL VEG. HEALTH #12;1313 Vegetation Health (VH) System · Satellites: NOAA · Sensor

Kuligowski, Bob

35

Transmission scheduling for wireless and satellite systems

  MIT - DSpace

Summary: We study queuing systems with time-varying service rates, as a natural model of satellite and wireless communication systems. Packets arrive at a satellite to be transmitted to one of the sub-regions (channels) in a service ...

Ganti, Anand, 1975-
2003-01-01

36

Helios: Heterogeneous Multiprocessing with Satellite Kernels

  Computer Technologies and Information Sciences Websites

Summary: Helios: Heterogeneous Multiprocessing with Satellite Kernels Edmund B. Nightingale Microsoft Research Galen Hunt Microsoft Research ABSTRACT Helios is an operating system designed to simplify the task of writ- ing, deploying, and tuning applications for heterogeneous platforms. Helios introduces satellite

Brown, Angela Demke

37

Satellite altimeter remote sensing of ice caps 

  Edinburgh, University of - Research Archive

Summary: This thesis investigates the use of satellite altimetry techniques for measuring surface elevation changes of ice caps. Two satellite altimeters, Radar Altimeter 2 (RA-2) and Geoscience Laser Altimeter System (GLAS) are ...

Rinne, Eero Juhani
2011-11-24

38

Advanced hybrid satellite andAdvanced hybrid satellite and terrestrial system architecture forterrestrial system architecture for

  Engineering Websites

Summary: Advanced hybrid satellite andAdvanced hybrid satellite and terrestrial system architecture Iapichino 1st phase of Ph.D. research on ``Ad hoc mobility in satellite-based networks for security communications: Satellite links Mobile ad-hoc mesh network Conclusions Future work Main achievements Bibliography

Gesbert, David

39

Reliable Multicast Transport by Satellite: a Hybrid Satellite/Terrestrial Solution with Erasure Codes

  Computer Technologies and Information Sciences Websites

Summary: multipoint communication service. In the context of reliable multicast communications, a new hybrid satellite/terrestrial approach is proposed. It aims at reducing the overall communication cost using satellite broadcasting onlyReliable Multicast Transport by Satellite: a Hybrid Satellite/Terrestrial Solution with Erasure

Mailhes, Corinne

40

Satellite Transport Protocol (STP): An SSCOPbased Transport Protocol for Datagram Satellite Networks

  Computer Technologies and Information Sciences Websites

Summary: challenges of data communications over satellite networks is the efficient transport of data over connections1 Satellite Transport Protocol (STP): An SSCOP­based Transport Protocol for Datagram Satellite in a datagram­based satellite data network. This protocol operates with high throughput and efficiency over

California at Berkeley, University of

41

ATS 351, Spring 2010 Satellite 50 points

  Geosciences Websites

Summary: ATS 351, Spring 2010 Lab #8 Satellite ­ 50 points 1. (3 points) What is the polarization temperature measured by a satellite. What are some factors that affect the emissivity of a surface? 5. (5 visible and infrared satellite imagery? Explain. Give an advantage and a disadvantage for each. #12;7. (7

Rutledge, Steven

42

Relations between Kauffman and Homfly satellite invariants

  Mathematics Websites

Summary: Relations between Kauffman and Homfly satellite invariants H. R. Morton and N. D. A. Ryder, to the general Kauffman and Homfly satellite invariants. 1 Introduction The result of Rudolph [5] relating. In this paper we show how Rudolph's result can be extended to general Kauffman satellite invariants. Our results

Morton, Hugh

43

Instant Active Positioning with One LEO Satellite

  Engineering Websites

Summary: on the earth's surface and a single low earth orbit LEO satellite makes it possible to derive range and range-satellite positioning is based on measure- ments of range and range rate. The range between the satellite and the UT-spectrum signal, as in GPS. Hence the delay measurement resolution is relatively high. Range rate is derived from

Levanon, Nadav

44

Dynamics and Control of Electromagnetic Satellite Formations

  Engineering Websites

Summary: Dynamics and Control of Electromagnetic Satellite Formations Umair Ahsun, David W. Miller June 2007 SSL # 12-07 #12;2 #12;Dynamics and Control of Electromagnetic Satellite Formations by Umair Ahsun B page] #12;3 Dynamics and Control of Electromagnetic Satellite Formations by Umair Ahsun Abstract


45

SCTP over Satellite Networks Shaojian Fu

  Computer Technologies and Information Sciences Websites

Summary: of SCTP for data communications over satellite links. We describe SCTP features that allow SCTP to betSCTP over Satellite Networks Shaojian Fu Mohammed Atiquzzaman School of Computer Science University of Oklahoma, Norman, OK 73019-6151. William Ivancic Satellite Networks & Architectures Branch NASA Glenn

Atiquzzaman, Mohammed

46

Satellite Navigation Integrity Assurance: Lessons Learned

  Engineering Websites

Summary: Satellite Navigation Integrity Assurance: Lessons Learned from Hurricane Katrina ION GNSS 2008 by the FAA Satellite Navigation Program Office #12;17 September 2008 Lessons Learned from Hurricane Katrina 2 ­ Failure to adapt to model changes after 1965 · Lessons for Satellite Navigation Integrity Design ­ Need

Stanford University

47

The Aerospace Corporation 2009 Communication Satellite Systems

  Computer Technologies and Information Sciences Websites

Summary: © The Aerospace Corporation 2009 Communication Satellite Systems Trends and Network Aspects Paul://www.aero.org/ Lee Center, Caltech 13 April 2009 #12;22 Communication Satellites · Brief History by Decade · Trends: ­ Communication Satellites, fifth edition, by D. Martin, P. Anderson, L. Bartamian, Aerospace / AIAA Press, 2006

Low, Steven H.

48

Unicast-Multicast Bridging for CDEEP EDUSAT Satellite Network

  Computer Technologies and Information Sciences Websites

Summary: Unicast-Multicast Bridging for CDEEP EDUSAT Satellite Network Thesis submitted in partial #12;Abstract Satellite communication networks today are used for educational purposes. These networks interested in joining the educational programmes through the satellite must setup a satellite transceiver

Iyer, Sridhar

49

Information Delivery Through Broadcasting in Satellite Communication Networks

  Engineering Websites

Summary: Information Delivery Through Broadcasting in Satellite Communication Networks Leandros Tassiulas­range multicasting capability of satellites and the asymmetry of satellite communications (high bandwidth downlink. We consider a data broadcasting model that is encountered in most asymmetric satellite communication

Tassiulas, Leandros

50

Optimal Energy Allocation and Admission Control for Communications Satellites

  Computer Technologies and Information Sciences Websites

Summary: 1 Optimal Energy Allocation and Admission Control for Communications Satellites Alvin Fu, Eytan control for communications satellites in earth orbit. These satellites receive requests for transmis- sion allocation problems in wireless commu- nications. Keywords-- Satellite, Communication, Resource Alloca- tion

Modiano, Eytan

51

Sweeping and shaking dwarf satellites

  Astrophysics (arXiv)

Summary: We present the first high-resolution N-Body/SPH simulations that follow the evolution of low surface brightness disk satellites in a primary halo containing both dark matter and a hot gas component. Tidal shocks turn the stellar disk into a spheroid with low $v/\\sigma$ and remove most of the outer dark and baryonic mass. In addition, by weakening the potential well of the dwarf, tides enhance the effect of ram pressure, and the gas is stripped down to radius three times smaller than the stellar component A very low gas/stars ratio results after several Gyr, similarly to what seen in dwarf spheroidal satellites of the Milky Way and M31.

Lucio Mayer; James Wadsley
2003-09-02

52

Star Formation in Satellite Galaxies

  CERN Preprints

Summary: The study of satellite galaxies can provide information on the merging and aggregation processes which, according to the hierarchical clustering models, form the larger spiral galaxies we observe. With the aim of testing hierarchical models of galaxy formation, we have conducted an observational program which comprises H$\\alpha$ imaging for both the parent and the satellite galaxies, taken from the compilation by Zaritsky et al. (1997) that contains 115 galaxies orbiting 69 primary isolated spiral galaxies. We have observed a subsample of 37 spiral and irregular galaxies taken from the compilation mentioned above. The aim of this study is to determine star formation properties of the sample galaxies. In this work we present the preliminary results of this program that we have carried out with the 1.8-m Vatican Telescope (VATT).

Funes, S J; Prada, F; Azzaro, M; Ribeiro, M B; SJ, Jose G. Funes; Gutierrez, Carlos M.; Prada, Francisco; Azzaro, Marco; Ribeiro, Marcelo B.
2003-01-01

53

Star Formation in Satellite Galaxies

  Astrophysics (arXiv)

Summary: The study of satellite galaxies can provide information on the merging and aggregation processes which, according to the hierarchical clustering models, form the larger spiral galaxies we observe. With the aim of testing hierarchical models of galaxy formation, we have conducted an observational program which comprises H$\\alpha$ imaging for both the parent and the satellite galaxies, taken from the compilation by Zaritsky et al. (1997) that contains 115 galaxies orbiting 69 primary isolated spiral galaxies. We have observed a subsample of 37 spiral and irregular galaxies taken from the compilation mentioned above. The aim of this study is to determine star formation properties of the sample galaxies. In this work we present the preliminary results of this program that we have carried out with the 1.8-m Vatican Telescope (VATT).

Jose G. Funes SJ; Carlos M. Gutierrez; Francisco Prada; Marco Azzaro; Marcelo B. Ribeiro
2003-09-22

54

Asteroseismology with the WIRE satellite

  Astrophysics (arXiv)

Summary: I give a summary of results from the WIRE satellite, which has been used to observe bright stars from 1999-2000 and 2003-2006. The WIRE targets are monitored for up to five weeks with a duty cycle of 30-40%. The aim has been to characterize the flux variation of stars across the Hertzsprung-Russell diagram. I present an overview of the results for solar-like stars, delta Scuti stars, giant stars, and eclipsing binaries.

H. Bruntt
2007-02-01

55

Picard satellite for solar astrometry

  CERN Preprints

Summary: The Picard solar satellite has been launched on June 15, 2010. This mission is dedicated to the measurement of the solar diameter with an expected accuracy of milliarcseconds of arc. The radiometer onboard is to measure the total solar irradiance. The final goal is the evaluation of the W, the logarithmic ratio of radius and luminosity. This parameter will help the climatologists to recover past values of the solar luminosity when the radius is available from ancient eclipses data.

Sigismondi, Costantino
2011-01-01

56

The orbital poles of Milky Way satellite galaxies: a rotationally supported disc-of-satellites

  Astrophysics (arXiv)

Summary: Available proper motion measurements of Milky Way (MW) satellite galaxies are used to calculate their orbital poles and projected uncertainties. These are compared to a set of recent cold dark-matter (CDM) simulations, tailored specifically to solve the MW satellite problem. We show that the CDM satellite orbital poles are fully consistent with being drawn from a random distribution, while the MW satellite orbital poles indicate that the disc-of-satellites of the Milky Way is rotationally supported. Furthermore, the bootstrapping analysis of the spatial distribution of theoretical CDM satellites also shows that they are consistent with being randomly drawn. The theoretical CDM satellite population thus shows a significantly different orbital and spatial distribution than the MW satellites, most probably indicating that the majority of the latter are of tidal origin rather than being DM dominated sub-structures. A statistic is presented that can be used to test a possible correlation of satellite galaxy orbits with their spatial distribution.

Manuel Metz; Pavel Kroupa; Noam I. Libeskind
2008-02-26

57

Satellite-based quantum clock synchronization

  CERN Preprints

Summary: We propose a practical satellite-based quantum clock synchronization scheme with dispersion cancellation and by taking into account effects of gravitational frequency shift of the Earth. Two frequency entangled pulses are employed to synchronize two clocks, one at a ground station and the other at a satellite. The time discrepancy of the two clocks is introduced into the pulses by moving mirrors and is extracted by measuring the coincidence rate of the pulses in the interferometer. We find that the pulses are distorted due to effects of the gravitational frequency shift when they propagate between the Earth and the satellite. It is shown that the coincidence rate as well as precision of the time discrepancy are remarkably affected by gravitational frequency shift effects both for the low earth orbits satellite and geostationary earth orbits satellite cases. We also find that the precision of the clock synchronization are sensitive to the source parameters and the altitude of the satellite. Our proposal can be...

Wang, Jieci; Jing, Jiliang; Fan, Heng
2015-01-01

58

to this Satellite Seminar broadcast!

  CiteSeer

Summary: Thank you for participating in this ISM Satellite Seminar. We hope you find today’s session to be a rewarding educational experience. PLEASE GIVE US YOUR FEEDBACK! Please remember to complete the program evaluation for today's program online via the ISM Web site at: www.ism.ws/surveys/index.cfm?SurveyID=334 All materials contained in this Program Handbook are the property of the Institute for Supply Management (ISM), unless otherwise noted. Members of our seminar panel may have provided additional information and materials for your use. Please make sure that the proper source is credited if you use these materials when you return to your organization. The statements and opinions expressed by the panelists in this program are solely those of the individuals, and are not necessarily endorsed by ISM. © January 2003 by the Institute for Supply Management (ISM). No part of these videos and accompanying materials, including all pictorial images, motion picture, and sound elements or text, may be reproduced in any manner without the written permission of ISM. Permission is hereby granted for downlink site coordinators to make enough copies of this Program Handbook for all participants at their downlink site. The licensing agreement for this program allows downlink sites to make one videotape recording of the satellite seminar — as it is being transmitted live — for use solely by the licensed organization for educational purposes for the life of the recorded copy. The satellite seminar may not be edited or altered. The videotape may be used strictly for educational activities, and may not be distributed to individuals. Mark your Calendar and Plan to Join Us

unknown authors
2004-01-01

59

Satellite Ecology: The Dearth of Environment Dependence

  Astrophysics (arXiv)

Summary: Using the Sloan Digital Sky Survey (SDSS) galaxy group catalogue of Yang et al. (2007), we study the average colour and average concentration of satellite galaxies as function of (i) their stellar mass, (ii) their group mass, and (iii) their group-centric radius. We find that the colours and concentrations of satellite galaxies are (almost) completely determined by their stellar mass. In particular, at fixed stellar mass, the average colours and concentrations of satellite galaxies are independent of either halo mass or halo-centric radius. We find clear evidence for mass segregation of satellite galaxies in haloes of all masses, and argue that this explains why satellites at smaller halo-centric radii are somewhat redder and somewhat more concentrated. In addition, the weak colour and concentration dependence of satellite galaxies on halo mass is simply a reflection of the fact that more massive haloes host, on average, more massive satellites. Combining these results with the fact that satellite galaxies are, on average, redder and somewhat more concentrated than central galaxies of the same stellar mass, the following picture emerges: galaxies become redder and somewhat more concentrated once they fall into a bigger halo (i.e., once they become a satellite galaxy). This is a clear manifestation of environment dependence. However, there is no indication that the magnitude of the transformation (or its timescale) depends on environment; a galaxy undergoes a transition when it becomes a satellite, but it does not matter whether it becomes a satellite of a small (Milky Way sized) halo, or of a massive cluster. We discuss the implication of this `dearth' of environment dependence for the physical processes responsible for transforming satellite galaxies.

Frank C. van den Bosch; Anna Pasquali; Xiaohu Yang; H. J. Mo; Simone Weinmann; Daniel H. McIntosh; Daniel Aquino
2008-05-01

60

A Search for Satellite around Ceres

  CERN Preprints

Summary: We conducted a satellite search around the dwarf planet 1 Ceres using Hubble Space Telescope and ground-based Palomar data. No candidate objects were found orbiting Ceres in its entire stability region down to ~500km from the surface of Ceres. Assuming a satellite would have the same albedo as Ceres, which has a visual geometric albedo of 0.07-0.10, our detection limit is sensitive to satellites larger than 1-2 km in diameter.

Bieryla, A; Young, E F; McFadden, L A; Russell, C T; Stern, S A; Sykes, M V; Gladman, B
2011-01-01

61

SaVi: satellite constellation visualization

  CERN Preprints

Summary: SaVi, a program for visualizing satellite orbits, movement, and coverage, is maintained at the University of Surrey. This tool has been used for research in academic papers, and by industry companies designing and intending to deploy satellite constellations. It has also proven useful for demonstrating aspects of satellite constellations and their geometry, coverage and movement for educational and teaching purposes. SaVi is introduced and described briefly here.

Wood, Lloyd
2012-01-01

62

Origin of Europa and the Galilean Satellites

  CERN Preprints

Summary: Europa is believed to have formed near the very end of Jupiter's own accretion, within a circumplanetary disk of gas and solid particles. We review the formation of the Galilean satellites in the context of current constraints and understanding of giant planet formation, focusing on recent models of satellite growth within a circumjovian accretion disk produced during the final stages of gas inflow to Jupiter. In such a disk, the Galilean satellites would have accreted slowly, in more than 10^5 yr, and in a low pressure, low gas density environment. Gravitational interactions between the satellites and the gas disk lead to inward orbital migration and loss of satellites to Jupiter. Such effects tend to select for a maximum satellite mass and a common total satellite system mass compared to the planet's mass. One implication is that multiple satellite systems may have formed and been lost during the final stages of Jupiter's growth, with the Galilean satellites being the last generation that survived as gas in...

Canup, Robin M
2008-01-01

63

A Search for Distant Satellites of Neptune

  CiteSeer

Summary: The recent discovery of two distant satellites of Uranus suggests that there could be similar bodies orbiting Neptune. Previous surveys for distant satellites of Neptune have had relatively bright magnitude limits (B J ' 20:5) and would have missed satellites with magnitudes and colours similar to the 2 recently discovered Uranian satellites (R 20:4 and R 21:9). We have searched for satellites of Neptune to a limiting magnitude of R 21 in a 0:12 ffi region centred on the planet. This search is up to 2 magnitudes deeper than the previous wide field search for distant satellites by the UK Schmidt Telescope. Nereid was easily recovered by the search and no large variations of its magnitude were detected. Keywords: planets and satellites: Neptune, Nereid 1 Introduction The recent discovery of two distant satellites of Uranus (Gladman et al. 1997) suggests similar bodies could be orbiting Neptune. Several surveys have looked for distant satellites of Neptune (Kuiper 1949, Ku...

Michael Brown And; Michael J. I. Brown; Rachel L. Webster

64

Origin of Europa and the Galilean Satellites

  Astrophysics (arXiv)

Summary: Europa is believed to have formed near the very end of Jupiter's own accretion, within a circumplanetary disk of gas and solid particles. We review the formation of the Galilean satellites in the context of current constraints and understanding of giant planet formation, focusing on recent models of satellite growth within a circumjovian accretion disk produced during the final stages of gas inflow to Jupiter. In such a disk, the Galilean satellites would have accreted slowly, in more than 10^5 yr, and in a low pressure, low gas density environment. Gravitational interactions between the satellites and the gas disk lead to inward orbital migration and loss of satellites to Jupiter. Such effects tend to select for a maximum satellite mass and a common total satellite system mass compared to the planet's mass. One implication is that multiple satellite systems may have formed and been lost during the final stages of Jupiter's growth, with the Galilean satellites being the last generation that survived as gas inflow to Jupiter ended. We conclude by discussing open issues and implications for Europa's conditions of formation.

Robin M. Canup; William R. Ward
2008-12-30

65

Satellites of the largest Kuiper belt objects

  Astrophysics (arXiv)

Summary: We have searched the four brightest objects in the Kuiper belt for the presence of satellites using the newly commissioned Keck Observatory Laser Guide Star Adaptive Optics system. Satellites are seen around three of the four objects: Pluto (whose satellite Charon is well-known), 2003 EL61, and 2003 UB313. The object 2005 FY9, the brightest Kuiper belt object after Pluto, does not have a satellite detectable within 0.4 arcseconds with a brightness of more than 0.5% of the primary. The presence of satellites to 3 of the 4 brightest Kuiper belt objects is inconsistent with the fraction of satellites in the Kuiper belt at large at the 99.1% confidence level, suggesting a different formation mechanism for these largest KBO satellites. The satellites of 2003 EL61 and 2003 UB313, with fractional brightnesses of 5% and 2% of their primaries, respectively, are significantly fainter relative to their primaries than other known Kuiper belt object satellites, again pointing to possible differences in their origin.

M. E. Brown; M. A. van Dam; A. H. Bouchez; D. Le Mignant; R. D. Campbell; J. C. Y. Chin; A. Conrad; S. K. Hartman; E. M. Johansson; R. E. Lafon; D. L. Rabinowitz; P. J. Stomski, Jr.; D. M. Summers; C. A. Trujillo; P. L. Wizinowich
2005-10-03

66

Ravens satellite mission concept study

  CERN Preprints

Summary: The concept for Ravens satellite mission was proposed in response to a CSA AO for potential Canadian mission contributions to the International Living With a Star (ILWS) program. Ravens was conceived of to fill an important gap in the ILWS program: global imaging. Ravens will build on the heritage of world-class global imaging carried out in Canada. It would do much more than provide global observations to complete the system level capabilities of ILWS. Ravens would be comprised of two satellites on elliptical polar orbits, relatively phased on those orbits to provide the first-ever continuous (ie., 24 hours per day 7 days per week) global imaging of the northern hemisphere auroral and polar cap regions. This would provide the first-ever unbroken sequences of global images of the auroral response during long duration geomagnetic processes like storms and steady magnetospheric convection events. Ravens could track the spatio-temporal evolution of the global electron and proton auroral distribution, and would o...

Donovan, Eric F
2011-01-01

67

Dynamics of the Galaxy's Satellites

  Astrophysics (arXiv)

Summary: The Milky Way's satellites provide unique information about the density of the Galactic halo at large radii. The inclusion of even a few rather inaccurate proper motions resolves an ambiguity in older mass estimates in favour of higher values. Many of the satellites are concentrated into streams. The dynamics of the Magellanic Stream provided an early indication that the halo reaches out to beyond 100 kpc. Tidal forces between the Clouds are currently disturbing the Clouds' internal dynamics. One would expect this damage to worsen rapidly as the tidal field of the MW excites the eccentricity of the Clouds' mutual orbit. This process, which has yet to be completely modelled, is important for understanding the degree of self-lensing in searches for gravitational lensing events. The Sagittarius Dwarf galaxy very likely contributes significantly to the Galactic warp. The direction of the warp's line of nodes is incorrectly predicted by the simplest models of the Dwarf's orbit. More sophisticated models, in which a complex distribution of stripped dark matter is predicted, may be more successful.

James Binney
2000-06-28

68

ACCROISSEMENT DE LA LUMINOSIT D'UN SPECTROMTRE 03B2 R. BOVING, J. PIRON et A. JONS,

  Physics Websites

Summary: , avec fer, est composé de deux secteurs et d'une lentille de «Glaser». On a étudié un dispositif de. - This spectrometer, with iron, is made of two sectors and a "Glaser's" lens. In order to increase the luminosity lentille de « Glaser » a été utilisée (longueur : 154 cm). Elle n'est pas le dispositifle plus pratique

Paris-Sud XI, Université de

69

National Satellite Technology Program Dr. Turki Al-Saud

  Engineering Websites

Summary: National Satellite Technology Program Dr. Turki Al-Saud KACST #12;National Satellite Technology Program Nano Satellites Program Remote Sensing Satellites Program Going big in size, weight and ambition (The GEO Program) #12;National Satellite Technology Program Space Research Institute (SRI

Stanford University

70

Sequoia 2000 Metadata Schema For Satellite Images

  CiteSeer

Summary: Sequoia 2000 schema development is based on emerging geospatial standards to accelerate development and facilitate data exchange. This paper focuses on the metadata schema for digital satellite images. We examine how satellite metadata are defined, used, and maintained. We discuss the geospatial

Jean T. Anderson; Michael Stonebraker
2000-01-01

71

Numerical Homotopy Algorithms for Satellite Trajectory Control

  Mathematics Websites

Summary: ]) to a control engineering problem, which appeared as case study in the literature. Our methodology extendsNumerical Homotopy Algorithms for Satellite Trajectory Control by Pole Placement 1 Jan Verschelde 2 is to illustrate the application of numerical homotopy algorithms to control the trajectory of a satellite. We

Verschelde, Jan

72

Numerical Homotopy Algorithms for Satellite Trajectory Control

  Mathematics Websites

Summary: of our knowledge ­ to apply the new Pieri homotopies (see [6], [7] and [10]) to a control engineeringNumerical Homotopy Algorithms for Satellite Trajectory Control by Pole Placement1 Jan Verschelde2 is to illustrate the application of numerical homotopy algorithms to control the trajectory of a satellite. We

Verschelde, Jan

73

Opportunities and Challenges of Nano Satellites

  Plasma Physics and Fusion Websites

Summary: #12;2 AXELSPACE - Who are we? Space venture company specialized in nano-satellites. Developer of nano. of Tech. #12;5 University Space Engineering Consortium (UNISEC) Founded in 2002, obtained legal status for space development/utilization Technology development for nano-satellites and hybrid rockets http


74

Using Satellite Data to Forecast . Bleaching Events

  Environmental Sciences and Ecology Websites

Summary: 1 Using Satellite Data to Forecast . Bleaching Events . By Tyler Christensen . NOAA Coral Reef Watch Satellite Imagery Worksheet The main condition that is linked to coral bleaching is unusually high for the warmest month. One degree above that is the threshold temperature for coral bleaching, shown as the solid


75

Satellite Eye for Galathea 3 -Slutrapport

  Multidisciplinary Databases and Resources Websites

Summary: Satellite Eye for Galathea 3 - Slutrapport Charlotte Bay Hasager, Peter Brøgger Sørensen, Jacob L Abstract (in English) (max. 2000 char.): The Satellite Eye for Galathea 3 project started on the 10th March August 2006. The expedition lasted in total 256 days (8 months), and the Satelitte Eye project continued


76

INTRODUCTION Satellites contain onboard equipment for sens-

  Computer Technologies and Information Sciences Websites

Summary: INTRODUCTION Satellites contain onboard equipment for sens- ing Earth and space, and communications links that transmit the data back to Earth for pro- cessing. Depending on altitude and movement, satellites are classified into three types: geosyn- chronous Earth orbit (GEO), medium Earth orbit (MEO

Atiquzzaman, Mohammed

77

1, 337378, 2001 Modeling of satellite

  Computer Technologies and Information Sciences Websites

Summary: in monitoring of the chemical composition of the troposphere. The Total Ozone Mapping Spectrometer (TOMSACPD 1, 337­378, 2001 Modeling of satellite derived tropospheric ozone W. Peters et al. Title Page-transport modeling of the satellite observed distribution of tropical tropospheric ozone W. Peters1, M. Krol1, F

Boyer, Edmond

78

COORDINATED CONTROL OF SATELLITES: THE ATTITUDE CASE

  Engineering Websites

Summary: -controller structure for attitude synchronization of a satellite formation is presented. The design applies methods of the formation, while the rest are defined as followers which synchronize their attitude with the leader. We apply the approach to the design of an coordinated attitude control scheme for a two-satellite formation

Gravdahl, Jan Tommy

79

A networking perspective on satellite constellations

  Engineering Websites

Summary: satellites (moving away from north pole) Walker Delta or Ballard rosette Walker seamed polar star no orbital seam (coverage overlaps even more) ascending satellites (moving towards north pole) descending orbits. Walker developed `star' (polar seamed) and `delta' (rosette) constellations, using streets

Wood, Lloyd

80

Offshore wind resource assessment through satellite images

  Multidisciplinary Databases and Resources Websites

Summary: 1 Slide no. 4 Offshore wind resource assessment through satellite images Charlotte Bay Hasager Rev wind farm ·Demo of the Risø Wemsar Tool (RWT) #12;3 Slide no. Objective To use satellite SAR images for offshore wind ressource assessment in lieu of in-situ mast observations #12;4 Slide no


81

Capture of Irregular Satellites at Jupiter

  CERN Preprints

Summary: The irregular satellites of outer planets are thought to have been captured from heliocentric orbits. The exact nature of the capture process, however, remains uncertain. We examine the possibility that irregular satellites were captured from the planetesimal disk during the early Solar System instability when encounters between the outer planets occurred (Nesvorny, Vokrouhlicky & Morbidelli 2007, AJ 133; hereafter NVM07). NVM07 already showed that the irregular satellites of Saturn, Uranus and Neptune were plausibly captured during planetary encounters. Here we find that the current instability models present favorable conditions for capture of irregular satellites at Jupiter as well, mainly because Jupiter undergoes a phase of close encounters with an ice giant. We show that the orbital distribution of bodies captured during planetary encounters provides a good match to the observed distribution of irregular satellites at Jupiter. The capture efficiency for each particle in the original transplanetary d...

Nesvorny, D; Deienno, R
2014-01-01

82

A Feedback Implosion Suppression Algorithm for Satellite Reliable Multicast

  Engineering Websites

Summary: A Feedback Implosion Suppression Algorithm for Satellite Reliable Multicast Gun Akkor, John S. Baras, and Michael Hadjitheodosiou Center for Satellite and Hybrid Communication Networks, Institute multicast transport protocols operating over a satellite network. A reliable transport protocol needs

Baras, John S.

83

Turbo-Coded APSK Modulations Design for Satellite Broadband Communications

  Computer Technologies and Information Sciences Websites

Summary: Turbo-Coded APSK Modulations Design for Satellite Broadband Communications Riccardo De Gaudenzi with application to satellite broad- band communications. APSK represents an attractive modulation format systems. 1 Introduction Satellite communication systems strength lies in their ability to efficiently

Guillén i Fàbregas, Albert

84

Ion Micro-Propulsion and Cost Modeling for Satellite Clusters

  Engineering Websites

Summary: of satellites in a cluster are altered by "tidal" accelerations which are a function of the cluster baseline the relative positions of the satellites within allowable tolerances. Satellite mass, volume, and power


85

The Orbital Distribution of Satellite Galaxies

  Astrophysics (arXiv)

Summary: We measure the distribution of velocities for prograde and retrograde satellite galaxies using a combination of published data and new observations for 78 satellites of 63 extremely isolated disc galaxies (169 satellites total). We find that the velocity distribution is non-Gaussian (>99.9% confidence), but that it can be described as the sum of two Gaussians, one of which is broad (sigma = 176 \\pm 15 km/s), has a mean prograde velocity of 86 \\pm 30 km/s, and contains ~55% of the satellites, while the other is slightly retrograde with a mean velocity of -21 \\pm 22 km/s and sigma = 74 \\pm 18 km/s and contains ~45% of the satellites. Both of these components are present over all projected radii and found in the sample regardless of cuts on primary inclination or satellite disc angle. The double-Gaussian shape, however, becomes more pronounced among satellites of more luminous primaries. We remove the potential dependence of satellite velocity on primary luminosity using the Tully-Fisher relation and still find the velocity distribution to be asymmetric and even more significantly non-Gaussian. The asymmetric velocity distribution demonstrates a connection between the inner, visible disc galaxy and the kinematics of the outer, dark halo. The reach of this connection, extending even beyond the virial radii, suggests that it is imprinted by the satellite infall pattern and large-scale effects, rather than by higher-level dynamical processes in the formation of the central galaxy or late-term evolution of the satellites.

Stéphane Herbert-Fort; Dennis Zaritsky; Yeun Jin Kim; Jeremy Bailin; James E. Taylor
2007-11-26

86

Sinking Satellites and Tilting Disk Galaxies

  Astrophysics (arXiv)

Summary: The infall of a satellite galaxy onto a galactic disk generally brings in angular momentum that is not aligned with the axis of the disk. The main dynamical issues addressed are what fraction of the orbital angular momentum of the satellite and the associated energy is added to the disk, as opposed to being left in the halo, and whether the absorbed fraction is added coherently or thermalized in the disk. By employing fully self-consistent disk+halo+satellite N-body simulations, we study the particular case of the satellite and main halo having similar density profiles, with internal velocities having the ``cosmological'' scaling $\\sigma\\propto M^{1/3}$. We find that most of the orbital angular momentum of the infalling satellite is left in the tidally stripped satellite remnants, with only $2\\%$, $6\\%$ and $9\\%$ of the orbital angular momentum being transferred to disks and halos for $10\\%$, $20\\%$ and $30\\%$ disk-mass satellites respectively. Because the disks are tilted by the infall of $10\\%$, $20\\%$ and $30\\%$ disk-mass satellites by angles of $(2.9\\pm0.3)^\\circ$, $(6.3\\pm0.1)^\\circ$ and $(9.7\\pm0.2)^\\circ$ respectively, the kinetic energy associated with the vertical motion in the initial coordinate frame of the three disks is respectively increased by $(6\\pm3)\\%$, $(26\\pm3)\\%$ and $(51\\pm5)\\%$ whereas the corresponding disk thermal energy associated with the vertical random motion in the tilted coordinate frame is only increased by $(4\\pm3)\\%$, $(6\\pm2)\\%$ and $(10\\pm2)\\%$, respectively. Under our initial conditions, a satellite having up to 20\\% of the disk mass would produce little observable thickening whereas a 30\\% disk-mass satellite produces little observable thickening inside the half-mass radius of the disk but great damage beyond the half-mass radius.

Siqin Huang; R. G. Carlberg
1995-11-16

87

Spatial and luminosity distributions of galactic satellites

  CERN Preprints

Summary: We investigate the luminosity functions (LFs) and projected number density profiles of galactic satellites around isolated primaries of different luminosities. We measure these quantities for model satellites placed into the Millennium and Millennium II dark matter simulations by the GALFORM semi-analytic galaxy formation model for different bins of primary galaxy magnitude and we investigate their dependence on satellite luminosity. We compare our model predictions to the data of Guo et al. from the Sloan Digital Sky Survey Data Release 8 (SDSS DR8). First, we use a mock light-cone catalogue to verify that the method we used to count satellites in the SDSS DR8 is unbiased. We find that the radial distributions of model satellites are similar to those around comparable primary galaxies in the SDSS DR8, with only slight differences at low luminosities and small projected radii. However, when splitting the satellites by colour, the model and SDSS satellite systems no longer resemble one another, with many red m...

Guo, Quan; Eke, Vincent; Frenk, Carlos; Helly, John
2013-01-01

88

Gas Shepherding by an Infalling Satellite

  Astrophysics (arXiv)

Summary: I calculate the action of a satellite, infalling through dynamical friction, on a coplanar gaseous disk of finite radial extent. The disk tides, raised by the infalling satellite, couple the satellite and disk. Dynamical friction acting on the satellite then shrinks the radius of the coupled satellite-disk system. Thus, the gas is ``shepherded'' to smaller radii. In addition, gas shepherding produces a large surface density enhancement at the disk edge. If the disk edge then becomes gravitationally unstable and fragments, it may give rise to enhanced star formation. On the other hand, if the satellite is sufficiently massive and dense, the gas may be transported from $\\sim 100$ pc to inside of a 10 to 10s of parsecs before completely fragmenting into stars. I argue that gas shepherding may drive the fueling of active galaxies and central starbursts and I compare this scenario to competing scenarios. I argue that sufficiently large and dense super star clusters (acting as the shepherding satellites) can shepherd a gas disk down to ten to tens of parsecs. Inside of ten to tens of parsecs, another mechanism may operate, i.e., cloud-cloud collisions or a marginally (gravitationally) stable disk, that drives the gas $\\lesssim 1$ pc, where it can be viscously accreted, feeding a central engine.

P. Chang
2008-05-22

89

Probing Dark Matter Haloes with Satellite Kinematics

  Astrophysics (arXiv)

Summary: Using detailed mock galaxy redshift surveys we investigate to what extent the kinematics of large samples of satellites galaxies extracted from flux-limited surveys can be used to constrain halo masses. Previous host-satellite selection criteria yield relatively large fractions of interlopers and with a velocity distribution that, contrary to what has typically been assumed, differs strongly from uniform. A new adaptive selection criterion is proposed which yields much larger host-satellite samples and with strongly reduced interloper fractions. We show that satellite weighting, which occurs naturally when stacking many host-satellite pairs, introduces a bias towards higher velocity dispersions compared to the true, host-averaged mean. A further bias, in the same direction, is introduced when using flux-limited, rather than volume-limited surveys. We apply our adaptive selection criterion to the 2dFGRS and obtain a sample of 12613 satellite galaxies and 8004 host galaxies. The satellite kinematics are in excellent agreement with predictions based on the conditional luminosity function (CLF), providing independent, dynamical confirmation of the average mass-to-light ratios predicted by the CLF formalism.

Frank C. van den Bosch; Peder Norberg; H. J. Mo; Xiaohu Yang
2004-05-14

90

Luminous satellite galaxies in gravitational lenses

  Astrophysics (arXiv)

Summary: Substructures, expected in cold dark matter haloes, have been proposed to explain the anomalous flux ratios in gravitational lenses. About 25% of lenses in the Cosmic Lens All-Sky Survey (CLASS) appear to have luminous satellites within ~ 5 kpc/h of the main lensing galaxies, which are usually at redshift z ~ 0.2-1. In this work we use the Millennium Simulation combined with galaxy catalogues from semi-analytical techniques to study the predicted frequency of such satellites in simulated haloes. The fraction of haloes that host bright satellites within the (projected) central regions is similar for red and blue hosts and is found to increase as a function of host halo mass and redshift. Specifically, at z = 1, about 11% of galaxy-sized haloes (with masses between 10^{12} M_sun/h and 10^{13} M_sun/h) host bright satellite galaxies within a projected radius of 5 kpc/h. This fraction increases to about 17% (25%) if we consider bright (all) satellites of only group-sized haloes (with masses between 10^{13} M_sun/h and 10^{14} M_sun/h). These results are roughly consistent with the fraction (~ 25%) of CLASS lensing galaxies observed to host luminous satellites. At z = 0, only ~ 3% of galaxy-sized haloes host bright satellite galaxies. The fraction rises to ~ 6%, (10%) if we consider bright (all) satellites of only group-sized haloes at z = 0. However, most of the satellites found in the inner regions are `orphan' galaxies where the dark matter haloes have been completely stripped. Thus the agreement crucially depends on the true survival rate of these `orphan' galaxies. We also discuss the effects of numerical resolution and cosmologies on our results.

S. E. Bryan; S. Mao; S. T. Kay
2008-09-18

91

Satellite galaxies in cosmological dark matter halos

  Astrophysics (arXiv)

Summary: We present preliminary results from a series of high-resolution N-body simulations that focus on 8 dark matter halos each of order a million particles within the virial radius. We follow the time evolution of hundreds of individually tracked satellite galaxies and relate their physical properties to the differing halo environmental conditions. Our main science driver is to understand how satellite galaxies lose their mass and react to tidal stripping. Unlike previous work our results are performed in a fully self-consistent cosmological context. The preliminary results demonstrate that while environment may vary considerably with respects to formation time and richness of substructure, the satellites evolve similarly.

Stuart P. D. Gill; Alexander Knebe; Brad K. Gibson
2003-11-28

92

Networking using Direct Broadcast Satellite

  CiteSeer

Summary: In this paper, we present a networking architecture based on the DirecPC Direct Broadcast Satellite (DBS) system that supports rapid deployment and easy relocation. A fundamental characteristic of this network is its asymmetry --- the downlink has an aggregate bandwidth of 12 Mbps while the reverse channel, such as a dialup line, has a relatively low bandwidth. We describe our extension of the DirecPC routing scheme, which is designed for a single host, to support a subnet with multiple hosts connected to it. We also discuss performance results from UDP and TCP bulk transfers, and Web-like transfers. Finally, we describe how the hybrid subnet has been integrated with the MBone to support real-time audio/video dissemination. 1. Introduction With the surge in interest in the Internet in recent years, there have been several proposals for providing high-speed network connectivity to homes and offices. These include Hybrid Fiber Coax (HFC), such as those based on cable modem technology, ...

Venkata N. Padmanabhan
1996-01-01

93

The Transiting Exoplanet Survey Satellite

  CERN Preprints

Summary: The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its two-year mission, TESS will employ four wide-field optical CCD cameras to monitor at least 200,000 main-sequence dwarf stars with I<13 for temporary drops in brightness caused by planetary transits. Each star will be observed for an interval ranging from one month to one year, depending mainly on the star's ecliptic latitude. The longest observing intervals will be for stars near the ecliptic poles, which are the optimal locations for follow-up observations with the James Webb Space Telescope. Brightness measurements of preselected target stars will be recorded every 2 min, and full frame images will be recorded every 30 min. TESS stars will be 10-100 times brighter than those surveyed by the pioneering Kepler missio...

Ricker, George R; Vanderspek, Roland; Latham, David W; Bakos, Gaspar A; Bean, Jacob L; Berta-Thompson, Zachory K; Brown, Timothy M; Buchhave, Lars; Butler, Nathaniel R; Butler, R Paul; Chaplin, William J; Charbonneau, David; Christensen-Dalsgaard, Jorgen; Clampin, Mark; Deming, Drake; Doty, John; De Lee, Nathan; Dressing, Courtney; Dunham, E W; Endl, Michael; Fressin, Francois; Ge, Jian; Henning, Thomas; Holman, Matthew J; Howard, Andrew W; Ida, Shigeru; Jenkins, Jon; Jernigan, Garrett; Johnson, John Asher; Kaltenegger, Lisa; Kawai, Nobuyuki; Kjeldsen, Hans; Laughlin, Gregory; Levine, Alan M; Lin, Douglas; Lissauer, Jack J; MacQueen, Phillip; Marcy, Geoffrey; McCullough, P R; Morton, Timothy D; Narita, Norio; Paegert, Martin; Palle, Enric; Pepe, Francesco; Pepper, Joshua; Quirrenbach, Andreas; Rinehart, S A; Sasselov, Dimitar; Sato, Bun'ei; Seager, Sara; Sozzetti, Alessandro; Stassun, Keivan G; Sullivan, Peter; Szentgyorgyi, Andrew; Torres, Guillermo; Udry, Stephane; Villasenor, Joel
2014-01-01

94

Star Formation in Satellite Galaxies

  CERN Preprints

Summary: We present narrow-band observations of the H$\\alpha$ emission in a sample of 31 satellite orbiting isolated giant spiral galaxies. The sample studied spans the range $-19

Gutíerrez, C M; Funes, J G; Ribeiro, M B
2006-01-01

95

The MAP Satellite Feed Horns

  Astrophysics (arXiv)

Summary: We present the design, manufacturing methods, and characterization of 20 microwave feed horns currently in use on the Microwave Anisotropy Probe (MAP) satellite. The nature of the cosmic microwave background (CMB) anisotropy requires a detailed understanding of the properties of every optical component of a microwave telescope. In particular, the properties of the feeds must be known so that the forward gain and sidelobe response of the telescope can be modeled and so that potential systematic effects may be computed. MAP requires low emissivity, azimuthally symmetric, low-sidelobe feeds in five microwave bands (K, Ka, Q, V, and W) that fit within a constrained geometry. The beam pattern of each feed is modeled and compared with measurements; the agreement is generally excellent to the -60 dB level (80 degrees from the beam peak). This agreement verifies the beam-predicting software and the manufacturing process. The feeds also affect the properties and modeling of the microwave receivers. To this end, we show that the reflection from the feeds is less than -25 dB over most of each band and that their emissivity is acceptable. The feeds meet their multiple requirements.

C. Barnes; M. Limon; L. Page; C. Bennett; S. Bradley; M. Halpern; G. Hinshaw; N. Jarosik; W. Jones; A. Kogut; S. Meyer; O. Motrunich; G. Tucker; D. Wilkinson; E. J. Wollack
2003-01-10

96

Surface Plasmon Satellites in 2p X-Ray Satellite Spectra of Transition Metal Halides

  CiteSeer

Summary: The origin of high energy 2P1/2 and 2P3/2 x-ray satellites of titanium, copper and Nickel dihalides has been explained using plasmon theory with a new approach by considering both extrinsic and intrinsic contribution simultaneously. Our calculation shows that satellites are due to surface plasmon excitation. We also review the existing calculations and experimental measurements. Keywords X-ray satellite spectra; Plasmon; energy separation; Relative intensity; Intrinsic and extrinsic effects.

S. K. Srivastava; Amar Bahadur; Pankaj Kumar Singh

97

Anisotropies in the Distribution of Satellite Galaxies

  Astrophysics (arXiv)

Summary: We find that satellites of isolated disk galaxies at projected radii between 300 and 500 kpc are distributed asymmetrically about the parent galaxy and aligned preferentially with the disk minor axis. The dynamical timescale at these radii is sufficiently long that the shape of this distribution must reflect the formation history of the outer halo rather than its internal evolution. We also find that the orbital angular momenta of satellites at projected major axis distances of $\\ltsim$ 200 kpc tend to align with that of the central disk. These results demonstrate that satellites are dynamically related to their primary galaxy. Satellites drawn from current simulations of hierarchical galaxy formation exhibit neither the systematic alignment nor the net rotation with the central disk that we find in the data.

Dennis Zaritsky; Rodney Smith; Carlos S. Frenk; Simon D. M. White
1996-11-26

98

PRECIPITATION PROBABILITY AND SATELLITE RADIATION DATA

  CiteSeer

Summary: Window radiation is related to precipitation probabilities for different time periods following the satellite pass. Window radiation combined with cloud brightness is better related to precipitation probabilities than window radiation alone. 1.

Mae Lethbridge; Mae Lethbridge

99

Resource management for advanced transmission antenna satellites

  MIT - DSpace

Summary: In satellite communications, narrow spotbeams can provide high power and data rates to the desired location while reducing spatial interference. Advanced transmission antenna technology is critical to generate and switch ...

Chan, Vincent W. S.

100

Dynamics and control of electromagnetic satellite formations

  MIT - DSpace

Summary: Satellite formation flying is an enabling technology for many space missions, especially for space-based telescopes. Usually there is a tight formation-keeping requirement that may need constant expenditure of fuel or at ...

Ahsun, Umair, 1972-
2007-01-01

101

NOAA NESDIS CENTER for SATELLITE APPLICATIONS and

  Geosciences Websites

Summary: 1 NOAA NESDIS CENTER for SATELLITE APPLICATIONS and RESEARCH ALGORITHM THEORETICAL BASIS DOCUMENT.......................................................................................................9 1.1 Purpose of This Document ..................................................................................9 1.2 Who Should Use This Document


102

The Future of Global Navigation Satellite Systems

  CiteSeer

Summary: Abstract Global Navigation Satellite Systems (GNSSs) involve satellites, ground stations and user equipment, and are now used across many areas of society. The Global Positioning System (GPS) from the US is the best known, and only currently fully operational GNSS. Russia also operates its own (not fully deployed) GNSS called GLONASS. Fuelling growth in applications during the next decade will be next generation GNSSs that are currently being deployed and developed. Major components are the US’s modernized GPS and planned GPS-III, the revitalised GLONASS, and Europe’s planned GALILEO system. Furthermore, a number of Space Based Augmentation Systems (SBASs) and Regional Navigation satellite Systems (RNSSs) will add extra satellites and signals to the GNSS “mix”.

Chris Rizos

103

Emerging trends in the satellite industry

  MIT - DSpace

Summary: Risk aversion in the satellite industry has fostered long development cycles and low rates of innovation in the past. Emerging trends in propulsion technology development and spacecraft architecture design could lead to ...

Salazar, Vagn Knudsen
2012-01-01

104

Synthetic Aperture Radar Interferometry with 3 satellites

  MIT - DSpace

Summary: Our study investigates interferometric SAR (InSAR) post-processing height retrieval techniques. We explore the possible improvements by adding a third satellite to the two already in orbit, and examine some potential uses ...

Wong, Wallace D. (Wallace Dazheng)
2005-01-01

105

Saturn satellites as seen by Cassini Mission

  CERN Preprints

Summary: In this paper we will summarize some of the most important results of the Cassini mission concerning the satellites of Saturn. Given the long duration of the mission, the complexity of the payload onboard the Cassini Orbiter and the amount of data gathered on the satellites of Saturn, it would be impossible to describe all the new discoveries made, therefore we will describe only some selected, paramount examples showing how Cassini's data confirmed and extended ground-based observations. In particular we will describe the achievements obtained for the satellites Phoebe, Enceladus and Titan. We will also put these examples in the perspective of the overall evolution of the system, stressing out why the selected satellites are representative of the overall evolution of the Saturn system.

Coradini, A; Cerroni, P; Filacchione, G; Magni, G; Orosei, R; Tosi, F; Turrini, D
2009-01-01

106

Atmospheric structure determined from satellite data

  Texas A&M University - TxSpace

Summary: of the weighting function for each wavelength banc sensed by the satellite radiometers. A temperature is determined from the energy emitted in each wavelength band, and applied to a particular level in the atmosphere depending on the characteristics... horizontal soacing of satellite soundings is approximately the same as that for rawinsonde stations over the continental United States, and this spacing rema' ns nearly constant for all locations including oceanic and mountainous az'eas. An important...

Knight, Keith Shelburne
1978-01-01

107

A Satellite LO system B. G. Clark

  Physics Websites

Summary: , looking at the satellite beacon. The beacon is radiating at frequency (angular) f : exp(if t) This is received at station A as exp[if(t L a1 )] where L a1 is the path length from the satellite to station A. Similarly, station B receives exp[if(t L b1 )] At each station, we have a synthesizer (here assumed perfect

Groppi, Christopher

108

The Anisotropic Distribution of Satellite Galaxies

  Astrophysics (arXiv)

Summary: We identify satellites of isolated galaxies in SDSS and examine their angular distribution. Using mock catalogues generated from cosmological N-body simulations, we demonstrate that the selection criteria used to select isolated galaxies and their satellites must be very strict in order to correctly identify systems in which the primary galaxy dominates its environment. The criteria used in many previous studies instead select predominantly group members. We refine a set of selection criteria for which the group contamination is estimated to be less than 7% and present a catalogue of the resulting sample. The angular distribution of satellites about their host is biased towards the major axes for spheroidal galaxies and probably also for red disc galaxies, but is isotropic for blue disc galaxies, i.e. it is the colour of the host that determines the distribution of its satellites rather than its morphology. The similar anisotropy measured in this study as in studies that were dominated by groups implies that group-specific processes are not responsible for the angular distribution. Satellites that are most likely to have been recently accreted show a tendancy to lie along the same axis as the surrounding large scale structure. The orientations of isolated early and intermediate-type galaxies also align with the surrounding large scale structures. We discuss the origin of the anisotropic satellite distribution and consider the implications of our results, critically assessing the respective roles played by the orientation of the visible galaxy within its dark matter halo; anisotropic accretion of satellites from the larger scale environment; and the biased nature of satellites as tracers of the underlying dark matter subhalo population. (Abridged)

Jeremy Bailin; Chris Power; Peder Norberg; Dennis Zaritsky; Brad K. Gibson
2008-08-12

109

ANALYSIS OF HANDOVER CHARACTERISTICS IN SHADOWED LEO SATELLITE COMMUNICATION NETWORKS

  Engineering Websites

Summary: ANALYSIS OF HANDOVER CHARACTERISTICS IN SHADOWED LEO SATELLITE COMMUNICATION NETWORKS£ YOUNG HOON In the near future low earth orbit (LEO) satellite communication networks will partially substitute for fixed, ongoing calls may be dropped if satellite channels are shadowed. Therefore, in most LEO satellite

Sung, Dan Keun

110

Correspondence SATELLITE AND SURFACE TEMPERATURE DATA AT ODDS?

  Environmental Sciences and Ecology Websites

Summary: Correspondence SATELLITE AND SURFACE TEMPERATURE DATA AT ODDS? Reply to John R. Christy and Roy WNider (1994), a perception has been created in the popular media that satellite measurements of global environmental changes. We discuss key aspects of the satellite vs. surface and the satellite vs. model issues

Fridlind, Ann

111

Satellite Diversity Gain Over The LEOS Channel, Based CDMA Systems

  Computer Technologies and Information Sciences Websites

Summary: Satellite Diversity Gain Over The LEOS Channel, Based CDMA Systems Tarek Attia, Peter Sweeney: There is a trend for mobile satellite system architectures aimed at the deployment of multi-satellite cost and having low power demand. In present and next generation satellite systems, CDMA has been

Haddadi, Hamed

112

Using Internet nodes and routers onboard satellites W. Ivancic,

  Engineering Websites

Summary: Using Internet nodes and routers onboard satellites L. Wood,@ W. Ivancic, D. Hodgson,+* E. Miller router in Low Earth Orbit (CLEO) onboard a small satellite is one step towards extending the terrestrial onboard the UK-DMC disaster monitoring constellation satellite built by Surrey Satellite Technology Ltd

Wood, Lloyd

113

TOWARDS NAVIGATION BASED ON 120 SATELLITES: ANALYZING THE NEW SIGNALS

  Engineering Websites

Summary: is developing the Galileo system that promises to place 30 more satellite in medium Earth orbit Galileo and one satellite from the Chinese Compass have been launched. The new satellites and new signals signals from the Galileo and Compass satellite programs. We reveal the spread spectrum codes for all

Stanford University

114

Measuring Mass Loss Rates from Galactic Satellites

  Astrophysics (arXiv)

Summary: We present the results of a study that uses numerical simulations to interpret observations of tidally disturbed satellites around the Milky Way. When analysing the simulations from the viewpoint of an observer, we find a break in the slope of the star count and velocity dispersion profiles in our models at the location where unbound stars dominate. We conclude that `extra-tidal' stars and enhanced velocity dispersions observed in the outskirts of Galactic satellites are due to contamination by stellar debris from the tidal interaction with the Milky Way. However, a significant bound population can exist beyond the break radius and we argue that it should not be identified with the tidal radius of the satellite. We also develop and test a method for determining the mass loss rate from a Galactic satellite using its extra-tidal population. We apply this method to observations of globular clusters and dwarf spheroidal satellites of the Milky Way, and conclude that a significant fraction of both satellite systems are likely be destroyed within the next Hubble time. Finally, we demonstrate that this mass loss estimate allows us to place some limits on the initial mass function (IMF) of stars in a cluster from the radial dependence of its present day mass function (PDMF).

Kathryn V. Johnston; Steinn Sigurdsson; Lars Hernquist
1998-05-21

115

Satellites and Haloes of Dwarf Galaxies

  CERN Preprints

Summary: We study the abundance of satellite galaxies as a function of primary stellar mass using the SDSS/DR7 spectroscopic catalogue. In contrast with previous studies, which focussed mainly on bright primaries, our central galaxies span a wide range of stellar mass, 10^7.5 < M_*^pri/M_sun < 10^11, from dwarfs to central cluster galaxies. Our analysis confirms that the average number of satellites around bright primaries, when expressed in terms of satellite-to-primary stellar mass ratio (m_*^sat/M_*^pri), is a strong function of M_*^pri. On the other hand, satellite abundance is largely independent of primary mass for dwarf primaries (M_*^pri<10^10 M_sun). These results are consistent with galaxy formation models in the LCDM scenario. We find excellent agreement between SDSS data and semi-analytic mock galaxy catalogues constructed from the Millennium-II Simulation. Satellite galaxies trace dark matter substructure in LCDM, so satellite abundance reflects the dependence on halo mass, M_200, of both substru...

Sales, Laura V; White, Simon D M; Navarro, Julio F
2012-01-01

116

Satellite Systems around Galaxies in Hydrodynamic Simulations

  CERN Preprints

Summary: We investigate the properties of satellite galaxies formed in N-body/SPH simulations of galaxy formation in the $\\Lambda$CDM cosmology. The simulations include the main physical effects thought to be important in galaxy formation and, in several cases, produce realistic spiral discs. In total, a sample of 9 galaxies of luminosity comparable to the Milky Way was obtained. At magnitudes brighter than the resolution limit, $M_V=-12$, the luminosity function of the satellite galaxies in the simulations is in excellent agreement with data for the Local Group. The radial number density profile of the model satellites, as well as their gas fractions also match observations very well. In agreement with previous N-body studies, we find that the satellites tend to be distributed in highly flattened configurations whose major axis is aligned with the major axis of the (generally triaxial) dark halo. In 2 out of 3 systems with sufficiently large satellite populations, the satellite system is nearly perpendicular to the p...

Libeskind, N I; Frenk, C S; Okamoto, T; Jenkins, A; Libeskind, Noam I; Cole, Shaun; Frenk, Carlos S; Okamoto, Takashi; Jenkins, Adrian
2006-01-01

117

Star Formation in Satellite Galaxies

  Astrophysics (arXiv)

Summary: We present narrow-band observations of the H$\\alpha$ emission in a sample of 31 satellite orbiting isolated giant spiral galaxies. The sample studied spans the range $-19

C. M. Gutierrez; M. S. Alonso; J. G. Funes; M. B. Ribeiro
2006-04-14

118

L'ARN satellite du virus de la mosaque du concombre II. Etude de la relation virus-ARN satellite

  Physics Websites

Summary: L'ARN satellite du virus de la mosaïque du concombre II. Etude de la relation virus-ARN satellite de Recherches d'Avignon, F 84140 Montfavet. RÉSUMÉ Le lien entre la présence d'ARN-5 (ARN satellite isolats d'ARN satellite. concombre, Une dose de 5 x 10-' >g/ml (dose minimale) d'ARN-5 est requise pour

Paris-Sud XI, Université de

119

Why satellite networking often isn't really satellite networking, and what can be done about it

  Engineering Websites

Summary: LECTURE Why satellite networking often isn't really satellite networking, and what can be done about it: moving satellites towards a fuller networking role. Lloyd Wood Global Defense and Space Group, Cisco Systems Abstract Networking via satellites is currently done by a range of separate, non

Wood, Lloyd

120

Heat Transfer -1 A satellite in space orbits the sun. The satellite can be approximated as a flat plate with

  Computer Technologies and Information Sciences Websites

Summary: Heat Transfer - 1 A satellite in space orbits the sun. The satellite can be approximated as a flat the sun is a blackbody with radius and surface temperature given below. (25 %) (b) The satellite perpendicular to the radiation coming from the sun. Assuming the satellite is at a uniform temperature, find

Virginia Tech

121

6Name ________________________________ Satellite technology is everywhere! Right now, there are over 1587 working satellites orbiting

  Environmental Sciences and Ecology Websites

Summary: , there are over 1587 working satellites orbiting Earth. They represent over $160 billion in assets to the world years as new services are created, and better technology is developed. Satellites in the lowest orbits, called Low Earth Orbit (LEO) orbit between 300 to 1000 kilometers above the ground. Because Earth


122

Proposed Nomenclature for Surface Features on Pluto and Its Satellites and Names for Newly Discovered Satellites

  CERN Preprints

Summary: In anticipation of the July 2015 flyby of the Pluto system by NASA's New Horizons mission, we propose naming conventions and example names for surface features on Pluto and its satellites (Charon, Nix, Hydra, Kerberos, Styx) and names for newly discovered satellites.

Mamajek, Eric E; Cameron, David A; Olmedo, Manuel; Fogerty, Shane; Franklin, Eric; Lambrides, Erini; Hasan, Imran; Sarkis, Richard E; Thorndike, Stephen; Nordhaus, Jason
2015-01-01

123

Macho Parallaxes From A Single Satellite

  Astrophysics (arXiv)

Summary: Massive Compact Objects (Machos) are currently being discovered at substantially higher rates than would be expected from standard models of known stellar populations. To determine whether they are due to non-standard distri- butions of known populations or to a heretofore unknown (`dark') population, one must acquire more information about the individual events. Space-based parallaxes are potentially the best tool for extracting additional information. To leading order, parallax measurements by a single satellite result in a four- fold degeneracy: two possible values of $\\tilde v$ and two possible signs for the component of motion perpendicular to the projected satellite-Earth vector. It had been believed that a second satellite would be required to break this degeneracy. I show that the velocity difference between the satellite and the Earth allows one to partially or totally break the degeneracy using a single satellite. For most Macho events it is possible to measure $\\tilde v$ and $\\tilde r_e$. For some it is also possible to measure $\\Phi$. The proposed Space Infrared Telescope could measure $\\sim 100$ parallaxes per year by applying $\\sim 400\\,$hr of telescope time.

Andrew Gould
1994-08-10

124

On the Secular Behavior of Irregular Satellites

  Astrophysics (arXiv)

Summary: Although analytical studies on the secular motion of the irregular satellites have been published recently, these theories have not yet been satisfactorily reconciled with the results of direct numerical integrations. These discrepancies occur because in secular theories the disturbing function is averaged over orbital motions, whereas instead one should take into account some large periodic terms, most notably the so-called ``evection''. We demonstrate that such terms can be incorporated into the Kozai formalism, and that our synthetic approach produces much better agreement with results from symplectic integrations. Using this method, we plot the locations of secular resonances in the orbital-element space, and we note that the distribution of irregular satellite clusters appears to be non-random. We find that the large majority of irregular-satellite groups cluster close to the secular resonances, with several objects having practically stationary pericenters. None of the largest satellites belong to this class, so we argue that this dichotomy implies that the smaller near-resonant satellites might have been captured differently than the largest irregulars.

Matija Cuk; Joseph A. Burns
2004-08-05

125

Notes on the Missing Satellites Problem

  CERN Preprints

Summary: The Missing Satellites Problem (MSP) broadly refers to the overabundance of predicted Cold Dark Matter (CDM) subhalos compared to satellite galaxies known to exist in the Local Group. The most popular interpretation of the MSP is that the smallest dark matter halos in the universe are extremely inefficient at forming stars. The question from that standpoint is to identify the feedback source that makes small halos dark and to identify any obvious mass scale where the truncation in the efficiency of galaxy formation occurs. Among the most exciting developments in near-field cosmology in recent years is the discovery of a new population satellite galaxies orbiting the Milky Way and M31. Wide field, resolved star surveys have more than doubled the dwarf satellite count in less than a decade, revealing a population of ultrafaint galaxies that are less luminous that some star clusters. For the first time, there are empirical reasons to believe that there really are missing satellite galaxies in the Local Group, lu...

Bullock, James S
2010-01-01

126

Luminous satellite galaxies in gravitational lenses

  CERN Preprints

Summary: Substructures, expected in cold dark matter haloes, have been proposed to explain the anomalous flux ratios in gravitational lenses. About 25% of lenses in the Cosmic Lens All-Sky Survey (CLASS) appear to have luminous satellites within ~ 5 kpc/h of the main lensing galaxies, which are usually at redshift z ~ 0.2-1. In this work we use the Millennium Simulation combined with galaxy catalogues from semi-analytical techniques to study the predicted frequency of such satellites in simulated haloes. The fraction of haloes that host bright satellites within the (projected) central regions is similar for red and blue hosts and is found to increase as a function of host halo mass and redshift. Specifically, at z = 1, about 11% of galaxy-sized haloes (with masses between 10^{12} M_sun/h and 10^{13} M_sun/h) host bright satellite galaxies within a projected radius of 5 kpc/h. This fraction increases to about 17% (25%) if we consider bright (all) satellites of only group-sized haloes (with masses between 10^{13} M_sun/...

Bryan, S E; Kay, S T
2008-01-01

127

Complex Satellite Monitoring of Coastal Water Areas

  CiteSeer

Summary: Abstract- Possibilities of applying satellite means for monitoring of sea and ocean water areas are considered. Significant parameters of water environment registered by modern advanced space means and problems than can be solved using these means are analyzed. Some results obtained during complex satellite monitoring of anthropogenic influences on Mamala Bay water area (Honolulu, Hawaii) in 2002-2004 are given in this paper. Based on analysis results for optical (panchromatic, multispectral, hyperspectral) and radar satellite image processing, manifestations of anthropogenic influence on water environment were studied. These manifestations are related to changes in hydrodynamic parameters, hydrooptical and hydro-biological characteristics of nearsurface ocean layer. Effects of generation of “quasimonochromatic ” spectral harmonics of sea waves (?~10...150 m) due to ultrahigh frequency internal wave manifestations caused by a deep outfall are detected. Parameters of harmonics revealed in satellite imagery coincide with parameters of internal waves obtained from the results of sea truth measurements. Based on the results of satellite monitoring we have worked out recommendations on nature-conservative measures in the studied recreational area that can be realized also for other coastal water areas.

V. Bondur

128

Massive Satellites of Close-In Gas Giant Exoplanets

  CERN Preprints

Summary: We study the orbits, tidal heating and mass loss from satellites around close-in gas giant exoplanets. The focus is on large satellites which are potentially observable by their transit signature. We argue that even Earth-size satellites around hot Jupiters may be immune to destruction by orbital decay; detection of such a massive satellite would strongly constrain theories of tidal dissipation in gas giants, in a manner complementary to orbital circularization. The star's gravity induces significant periodic eccentricity in the satellite's orbit. The resulting tidal heating rates, per unit mass, are far in excess of Io's and dominate radioactive heating out to planet orbital periods of months for reasonable satellite tidal $Q$. Inside planet orbital periods of about a week, tidal heating can completely melt the satellite. Lastly, we compute an upper limit to the satellite mass loss rate due to thermal evaporation from the surface, valid if the satellite's atmosphere is thin and vapor pressure is negligible. ...

Cassidy, Timothy A; Arras, Phil; Johnson, Robert E; Skrutskie, Michael F
2009-01-01

129

8A Problem in Satellite Synchrony The THEMIS program has launched five satellites that will orbit earth at different distances to

  Environmental Sciences and Ecology Websites

Summary: 8A Problem in Satellite Synchrony The THEMIS program has launched five satellites that will orbit satellites orbiting Earth in the same plane. The closer-in satellite had a period of 4 hours, and the second;8 Answer Key: Problem 1 - Suppose you had two satellites orbiting Earth. The closer-in satellite had


130

On Asymmetric Distributions of Satellite Galaxies

  CERN Preprints

Summary: We demonstrate that the asymmetric distribution of M31 satellites cannot be produced by tides from the Milky Way as such effects are too weak. However, loosely bound associations and groups of satellites can fall into larger haloes and give rise to asymmetries. We compute the survival times for such associations. We prove that the survival time is always shortest in Keplerian potentials, and can be ~ 3 times longer in logarithmic potentials. We provide an analytical formula for the dispersal time in terms of the size and velocity dispersion of the infalling structure. We show that, if an association of ~10 dwarfs fell into the M31 halo, its present aspect would be that of an asymmetric disk of satellites. We also discuss the case of cold substructure in the Andromeda II and Ursa Minor dwarfs.

Bowden, A; Belokurov, V
2014-01-01

131

The morphological evolution of galaxy satellites

  Astrophysics (arXiv)

Summary: We study the evolution of galaxy satellites with high resolution N-body simulations. Satellites are modeled as replicas of typical low and high surface brightness galaxies (LSBs and HSBs). Encounters on high eccentricity orbits (as typical in hierarchical models of galaxy formation) strip LSBs of most of their stars and tend to decrease their surface brightness. On the contrary, bar instability in HSBs leads to substantial loss of angular momentum of the stellar component and to an increase of central surface brightness. In both cases the remnant resembles a spheroidal galaxy with an exponential surface brightness profile. A simple modeling of color evolution and interactions driven star formation gives M/L ratios for the remnants that are roughly consistent with observations. These results suggest an evolutionary scenario for the dwarf galaxies in our Local Group, faint dSphs being the descendents of LSBs and brighter dSphs/dEs being the final state of HSB satellites.

Lucio Mayer; Fabio Governato; Monica Colpi; Ben Moore; Thomas R. Quinn; Carlton M. Baugh
1999-03-30

132

Introducing Relativity in Global Navigation Satellite Systems

  General Relativity & Quantum Cosmology (arXiv)

Summary: Today, the Global Navigation Satellite Systems, used as global positioning systems, are the GPS and the GLONASS. They are based on a Newtonian model and hence they are only operative when several relativistic effects are taken into account. The most important relativistic effects (to order 1/c^2) are: the Einstein gravitational blue shift effect of the satellite clock frequency (Equivalence Principle of General Relativity) and the Doppler red shift of second order, due to the motion of the satellite (Special Relativity). On the other hand, in a few years the Galileo system will be built, copying the GPS system unless an alternative project is designed. In this work, it will be also shown that the SYPOR project, using fully relativistic concepts, is an alternative to a mere copy of the GPS system. According to this project, the Galileo system would be exact and there would be no need for relativistic corrections.

J. -F. Pascual-Sanchez
2006-12-13

133

Dwarf satellite galaxies in the modified dynamics

  Astrophysics (arXiv)

Summary: In the modified dynamics (MOND) the inner workings of dwarf satellites can be greatly affected by their mother galaxy-over and beyond its tidal effects. Because of MOND's nonlinearity a system's internal dynamics can be altered by an external field in which it is immersed (even when this field, by itself, is constant in space). As a result, the size and velocity dispersion of the satellite vary as the external field varies along its orbit. A notable outcome of this is a substantial increase in the dwarf's vulnerability to eventual tidal disruption-rather higher than Newtonian dynamics (with a dark-matter halo) would lead us to expect for a satellite with given observed parameters.

Rafael Brada; Mordehai Milgrom
2000-05-11

134

Satellite Earth Observation in Operational Oceanography

  CiteSeer

Summary: The role and contribution of satellite data in operational oceanography is reviewed, with emphasis on northern European seas. The possibility to observe various ocean parameters and processes by existing satellite sensors, such as optical instruments, infrared radiometers, passive Z. microwave radiometers, and active microwave systems altimeter, scatterometer, SAR is discussed. The basic parameters are: sea-surface temperature observed by infrared radiometers, ocean colour by spectrometers, sea-surface elevation by altimeters, and surface roughness by active and passive microwave systems, which can be used to derive surface wind and waves. A number of ocean processes can be derived from synoptic mapping of the basic parameters of larger sea areas, such as current patterns, fronts, eddies, water mass distribution, and various water quality Z. parameters chlorophyll, surface slicks, suspended sediments . The suitability of existing satellite data to fulfil the operational requirements fo...

Ola M. Johannessen; Stein Sandven; Stein S; Alastair D. Jenkins; Dominique Durand; Lasse H. Pettersson; Geir; Heidi Espedal
2000-01-01

135

Satellite Systems around Galaxies in Hydrodynamic Simulations

  Astrophysics (arXiv)

Summary: We investigate the properties of satellite galaxies formed in N-body/SPH simulations of galaxy formation in the $\\Lambda$CDM cosmology. The simulations include the main physical effects thought to be important in galaxy formation and, in several cases, produce realistic spiral discs. In total, a sample of 9 galaxies of luminosity comparable to the Milky Way was obtained. At magnitudes brighter than the resolution limit, $M_V=-12$, the luminosity function of the satellite galaxies in the simulations is in excellent agreement with data for the Local Group. The radial number density profile of the model satellites, as well as their gas fractions also match observations very well. In agreement with previous N-body studies, we find that the satellites tend to be distributed in highly flattened configurations whose major axis is aligned with the major axis of the (generally triaxial) dark halo. In 2 out of 3 systems with sufficiently large satellite populations, the satellite system is nearly perpendicular to the plane of the galactic disc, a configuration analogous to that observed in the Milk Way. The discs themselves are perpendicular to the minor axis of their host halos in the inner parts, and the correlation between the orientation of the galaxy and the shape of the halo persists even out to the virial radius. However, in one case the disc's minor axis ends up, at the virial radius, perpendicular to the minor axis of the halo. The angular momenta of the galaxies and their host halo tend to be well aligned.

Noam I Libeskind; Shaun Cole; Carlos S Frenk; Takashi Okamoto; Adrian Jenkins
2006-07-11

136

A relativistic and autonomous navigation satellite system

  General Relativity & Quantum Cosmology (arXiv)

Summary: A relativistic positioning system has been proposed by Bartolom\\'e Coll in 2002. Since then, several group developed this topic with different approaches. I will present a work done in collaboration with Ljubljana University and the ESA Advanced Concepts Team. We developed a concept, Autonomous Basis of Coordinates, in order to take advantage of the full autonomy of a satellite constellation for navigation and positioning, by means of satellite inter-links. I will present the advantages of this new paradigm and a number of potential application for reference systems, geophysics and relativistic gravitation.

Pacôme Delva; Andrej Cadez; Uros Kostic; Sante Carloni
2011-06-17

137

Internal waves and vortices in satellite images

  CERN Preprints

Summary: Some recent papers proposed the use of the satellite images of Google Earth in teaching physics, in particular to see some behaviours of waves. Reflection, refraction, diffraction and interference are easy to be found in these satellite maps. Besides Google Earth, other sites exist, such as Earth Observatory or Earth Snapshot, suitable for illustrating the large-scale phenomena in atmosphere and oceans In this paper, we will see some examples for teaching surface and internal sea waves, and internal waves and the K\\'arm\\'an vortices in the atmosphere. Aim of this proposal is attracting the interest of students of engineering schools to the physics of waves.

Sparavigna, Amelia Carolina
2012-01-01

138

Satellite Navigation in Vietnam & The NAVIS Centre

  Engineering Websites

Summary: Satellite Navigation in Vietnam & The NAVIS Centre TA HAI TUNG (PhD) NAVIS Centre, HUST, Vietnam GNSS Futures UNSW, Sydney, Australia, 7-8 July 2014 #12;Space Technology in Vietnam · 2006: the PM adopted the "STRATEGY FOR SPACE RESEARCH & APPLICATIONS

Sekercioglu, Y. Ahmet

139

Driving Innovation A Satellite Applications TIC

  Physics Websites

Summary: Projects #12;Driving Innovation SatApps TIC - goal `generating growth across the economy through new;Driving Innovation What does industry need from the SatApps TIC ? · Risk reduction ­ Prove that new Data Downlink & Processing Data Exploitation & Application Satellite Operations SatApps TIC aims


140

Cooperative Institute for Oceanographic Satellite Studies (CIOSS)

  Geosciences Websites

Summary: @coas.oregonstate.edu Collaborating with 22 CIOSS Fellows at OSU and UO. NOAA CIOSS Fellows: Paul Chang (STAR), Pablo Clemente-Colon (STAR), Paul DiGiacomo (STAR), David Foley (CoastWatch), Kent Hughes (STAR), Alexander Ignatov (STAR), Laury Miller (STAR), Michael Ondrusek (STAR), William Pichel (STAR) #12;CIOSS Theme 1: Satellite Sensors

Kurapov, Alexander

141

The chemical composition of the Galileian satellites

  Astrophysics (arXiv)

Summary: Using the semiclassical theory of dense matter proposed by P.Savic and R.Kasanin,the mean molecular masses of the Galilean satellites of Jupiter are determined.The calculated values are fitted by plausible combinations of chemical elements,and the results are in good agreement with the observations by "Galileo".Possible cosmogonical explanations are briefly discussed.

V. Celebonovic
1998-07-20

142

Asymmetric Warfare: M31 and its Satellites

  CERN Preprints

Summary: Photometric surveys of M31's halo vividly illustrate the wreckage caused by hierarchical galaxy formation. Several of M31's satellites are being disrupted by M31's tidal field, among them M33 and And I, while other tidal structures are the corpses of satellites already destroyed. The extent to which M31's satellites have left battle scars upon it is unknown; to answer this we need accurate orbits and masses of the perturbers. I focus here on M31's 150-kpc-long Giant Southern Stream (GSS) as an example of how these can be determined even in the absence of a visible progenitor. Comparing N-body models to photometric and spectroscopic data, I find this stream resulted from the disruption of a large satellite galaxy by a close passage about 750 Myr ago. The GSS is connected to several other debris structures in M31's halo. Bayesian sampling of the simulations estimates the progenitor's initial mass as log(Mstar/Msun) = 9.5 +- 0.2, showing it was one of the most massive Local Group galaxies until quite recently. T...

Fardal, Mark A
2009-01-01

143

A Satellite Ground Station Control System

  Mathematics Websites

Summary: software. For small student satellites, a simple and flexible ground station control system is necessary, and monitors the system running status. In this thesis, We shall analyze two existing ground station softwares: Mercury system and JStation. Then we shall present the design and implementation of the control system


144

Introduction satellite based scatterometers provide high

  Geosciences Websites

Summary: 30 Introduction satellite based scatterometers provide high resolution all-weather wind vector fields over the seas. Wind speed and wind direction are provided at high accuracy under all weather for the forecasting of fast developing and severe weather. Moreover, scatterometer wind fields are provided

Haak, Hein

145

PERFORMANCE EVALUATION OF NEMO IN SATELLITE NETWORKS

  Computer Technologies and Information Sciences Websites

Summary: of multiple IP-enabled devices on- board a Low Earth Orbit satellite (a mobile network on-board). NEMO. In addition, NEMO protocols can provide continuous connectivity at upper layers using nested NEMO (a mobile shows continuity of connections at upper layers and performance superiority of Saratoga to TCP for NEMO

Atiquzzaman, Mohammed

146

Ocean Surface Currents From Geostationary Satellite SST

  Geosciences Websites

Summary: Ocean Surface Currents From Geostationary Satellite SST -We are implementing and evaluating a feature tracking approach to estimate ocean surface currents. - This approach allows us to estimate in the global ocean where images are available. Uses include search and rescue, monitoring trajectories

Kurapov, Alexander

147

HORSESHOE PERIODIC ORBITS FOR SATURN COORBITAL SATELLITES

  Mathematics Websites

Summary: HORSESHOE PERIODIC ORBITS FOR SATURN COORBITAL SATELLITES Jaume Llibre and Merc`e Oll'e Dept. Matem conclude that there exist stable horseshoe periodic orbits which fit with the motion of Saturn coorbital­ stricted problem. 1. Introduction In 1981 the successful Voyager flights to Saturn confirmed the existence

Politècnica de Catalunya, Universitat

148

NOAA NESDIS CENTER for SATELLITE APPLICATIONS

  Geosciences Websites

Summary: #12;3 Critical Design Review Prepared By: 1 NOAA NESDIS CENTER for SATELLITE APPLICATIONS and RESEARCH DOCUMENT GUIDELINE DG-8.2.A CRITICAL DESIGN DOCUMENT GUIDELINE - APPENDIX Version 3.0 #12;2 TITLE: DG-8.2.A: CRITICAL DESIGN DOCUMENT

Kuligowski, Bob

149

SEMI EMPIRICAL SATELLITE MODELS Richard Perez1

  Renewable Energy Websites

Summary: University of New York, ASRC, Albany, NY, USA 2 GeoModel Solar, Bratislava, Slovakia Abstract This chapter discusses basic principles of solar irradiance modeling based on the use of input data from geostationary satellites and atmospheric models. Two operational approaches (SUNY/SolarAnywhere and SolarGIS) based

Perez, Richard R.

150

Total Solar Irradiance Satellite Composites and their

  Mathematics Websites

Summary: Chapter 12 Total Solar Irradiance Satellite Composites and their Phenomenological Effect on Climate. Phenomenological solar signature on climate 310 9. Conclusion 312 1. INTRODUCTION A contiguoustotal solar from each other, in particular about whether the TSI minimum during solar Cycles 22e23 (1995

Scafetta, Nicola

151

Transient Astronomy with the Gaia Satellite

  Physics Websites

Summary: Transient Astronomy with the Gaia Satellite Simon Hodgkin, Lukasz Wyrzykowski, Ross Burgon, Sergey SocietySimon Hodgkin, IoA, Cambridge, UK The ESA Gaia mission 2 http://www.rssd.esa.int/Gaia · 1 billion windows on transients across the universe, April 23-24 2012, Royal SocietySimon Hodgkin, IoA, Cambridge

Hinton, Jim

152

Satellite Tagging and Cardiac Physiology Reveal Niche

  Geosciences Websites

Summary: (SPOT), designed with a small Argos trans- mitter, that permits direct attachment to the shark_s dorsal salmon shark positions having errors under 1 km, based on Argos accuracies (Fig. 1 and table S2) uplinked to Argos satellites pro- vided track lengths of 351 T 38 days (mean T SE) and 8715 T 747 km (13

Luther, Douglas S.

153

Thursday, March 15, 2007 ICY SATELLITE SURFACES

  Physics Websites

Summary: - and nitrile-laced compounds at Phoebe and Dione. Ice-dominated Worlds: Spectral modeling of Tethys and Modeling [#2415] The icy saturnian satellites are slowly, if grudgingly, beginning to give up the secrets and topographic data were extracted. Geologic units were dated with cratering chronology models. 2:15 p

Rathbun, Julie A.

154

Isolated Galaxies and Isolated Satellite Systems

  CERN Preprints

Summary: We search for isolated galaxies using a volume-limited sample of galaxies with 0.02r_{vir,nei} and \\rho <\\bar{\\rho} well segregates the CIG galaxies. We confirm the morphology conformity between the host and their satellites, which suggests importance of hydrodynamic interaction among galaxies within their virial radii in galaxy evolution.

Ann, H B; Choi, Yun-Young
2009-01-01

155

Euler deconvolution in satellite geodesy Matthias Roth

  Geosciences Websites

Summary: Euler deconvolution in satellite geodesy Matthias Roth Institute of Geodesy, University of Stuttgart, Germany matthias.roth@gis.uni-stuttgart.de 1. Introduction Euler deconvolution is a semi with Thompson (1982) who used mag- netic data, Euler deconvolution became of great interest in research. Since

Stuttgart, Universität

156

The surprising inefficiency of dwarf satellite quenching

  CERN Preprints

Summary: We study dwarf satellite galaxy quenching using observations from the Geha et al. (2012) NSA/SDSS catalog together with LCDM cosmological simulations to facilitate selection and interpretation. We show that fewer than 30% of dwarfs (M* ~ 10^8.5-10^9.5 Msun) identified as satellites within massive host halos (Mhost ~ 10^12.5-10^14 Msun) are quenched, in spite of the expectation from simulations that half of them should have been accreted more than 6 Gyr ago. We conclude that whatever the action triggering environmental quenching of dwarf satellites, the process must be highly inefficient. We investigate a series of simple, one-parameter quenching models in order understand what is required to explain the low quenched fraction and conclude that either the quenching timescale is very long (> 9.5 Gyr, a "slow starvation" scenario) or that the environmental trigger is not well matched to accretion within the virial volume. We discuss these results in light of the fact that most of the low mass dwarf satellites in ...

Wheeler, Coral; Cooper, Michael C; Boylan-Kolchin, Mike; Bullock, James S
2014-01-01

157

Building technological capability within satellite programs in developing countries

  MIT - DSpace

Summary: Global participation in space activity is growing as satellite technology matures and spreads. Countries in Africa, Asia and Latin America are creating or reinvigorating national satellite programs. These countries are ...

Wood, Danielle Renee
2012-01-01

158

Improving TCP performance in mobile satellite IP communications

  Computer Technologies and Information Sciences Websites

Summary: (TCP) Motivation for TCP performance improvement Mobile satellite services risks uncertainties ethics concerns: unlicensed operators/users interfere with existing systems hack into existing systems license TCP performance in mobile satellite IP communications 9 Ethics Public vs. commercial needs: true

Trajkovic, Ljiljana

159

STABILITY OF SATELLITES IN CLOSELY PACKED PLANETARY SYSTEMS

  MIT - DSpace

Summary: We perform numerical integrations of four-body (star, planet, planet, satellite) systems to investigate the stability of satellites in planetary systems with tightly packed inner planets (STIPs). We find that the majority ...

Payne, Matthew J.

160

A Satellite Beacon Receiver using Digital Signal Processing Techniques

  CiteSeer

Summary: This paper describes the use of Digital Signal Processing techniques to Digitise and detect a beacon signal from a satellite. These techniques result in a cheaper Satellite Beacon Receiver, with an improved dynamic range and faster acquisition time. 1.

C. J. Kikkert; B. Bowthorpe

161

INSURED project (INtegrated Satellite UMTS Real Environment Demonstrator)

  Engineering Websites

Summary: satellite system (IRIDIUM) and a GSM network. The trials carried out with the demonstrator are of paramount; the first pre-operational IRIDIUM satellites are available for experimentation. The INSURED project

Vouyioukas, Demosthenes

162

Multidisciplinary Design Optimization Methodology for Distributed Satellite Systems

  CiteSeer

Summary: A multiobjective, multidisciplinary design optimization methodology for mathematically modeling the distributed satellite system (DSS) conceptual design problem as an optimization problem has been developed to advance the state-of-the-art in complex distributed satellite network design. An

Cyrus D. Jilla; D. Jilla
2004-01-01

163

Methods for verifying satellite precipitation estimates Elizabeth E. Ebert

  Geosciences Websites

Summary: 1 Methods for verifying satellite precipitation estimates Elizabeth E. Ebert Bureau of Meteorology, Melbourne, Australia Introduction Satellite precipitation estimates are widely used to measure global precipitation estimates are becoming increasingly available to the wider community. These precipitation

Ebert, Beth

164

Des satellites nous renvoient notre image Politique scientifique fdrale

  Mathematics Websites

Summary: Des satellites nous renvoient notre image Politique scientifique fédérale Martine STÉLANDRE Faites, HEPL Sualem, ISELL, Hemes et ULg 2 Les satellites observent la Terre En l'an 2002, plus de 5.000 satellites flottaient autour de la Terre, dont environ 600 sont en fonctionnement. Ce sont des outils

Liège, Université de

165

Revised 2007-Jan-09 Irregular Satellites of the Planets

  Physics Websites

Summary: Revised 2007-Jan-09 Irregular Satellites of the Planets: Capture Processes in the Early Solar in the Solar system possess irregular satellites, charac- terized by large, highly eccentric and/or inclined orbits that are distinct from the nearly circular, uninclined orbits followed by the regular satellites

Jewitt, David C.

166

Satellite Meeting to the EBBS 2007 Conference 15 September 2007

  Biology and Medicine Websites

Summary: Satellite Meeting to the EBBS 2007 Conference 15 September 2007 Stress, Brain and Behaviour Recent, an important goal of this meeting is to promote discussions. The Satellite will start at 10:30 and last till 17: Registration fees for the EBBS conference include participation of the Satellite. In case you want to attend

Treves, Alessandro

167

High Speed Internet Access Through Unidirectional Geostationary Satellite Channels

  Computer Technologies and Information Sciences Websites

Summary: High Speed Internet Access Through Unidirectional Geostationary Satellite Channels Ina Minei Reuven user to a direct satellite channel, at a speed 20 times faster than that of an average telephone modem. Communication over satellite links is often characterized by sporadic high bit-error rates and burst losses

Cohen, Reuven

168

The Anticoincidence System of the PAMELA Satellite Experiment

  Materials Science Websites

Summary: The Anticoincidence System of the PAMELA Satellite Experiment Design of the Data Acquisition System of the PAMELA Satellite Experiment - Design of the Data Acquisition System and Performance Studies Abstract PAMELA is a satellite-borne cosmic ray experiment. Its primary scientific objective is to study

Haviland, David

169

A Novel Dimensioning Method For High Throughput Satellite Design

  Physics Websites

Summary: A Novel Dimensioning Method For High Throughput Satellite Design Dimitri Serrano-Velarde, Emmanuel satellite (HTS) for broadband communications. The method is based on the optimization of performance is adaptable to any kind of service area. A digital video broadcasting satellite second generation (DVB-S2) air

Paris-Sud XI, Université de

170

2014 Benefits Satellite Office Schedule Date Time Location

  Biology and Medicine Websites

Summary: 2014 Benefits Satellite Office Schedule Date Time Location January 21st 1:00 ­ 4:00 pm Campus ­ 305 June 17th SATELLITE OFFICE CANCELLED July 15th 1:00 ­ 4:00 pm Campus Center - 309 August 19th 1 December 16th 1:00 ­ 4:00 pm Campus Center - 305 Satellite Offices provide a central location on campus

Zhou, Yaoqi

171

On the perturbations on satellites probing General Relativity

  General Relativity & Quantum Cosmology (arXiv)

Summary: Non-gravitational Yarkovsky-Rubincam effect for LAGEOS and LAGEOS 2 satellites used to probe General Relativity has been revealed by means of the Kolmogorov analysis of their perturbations. We present the method and its efficiency at modeling of generated systems with properties expected at the satellite laser ranging measurements and then at satellite residual data analysis.

S. Sargsyan; G. Yegorian; S. Mirzoyan
2013-12-19

172

Irregular Satellites of the Planets: Products of Capture

  Physics Websites

Summary: Irregular Satellites of the Planets: Products of Capture in the Early Solar System David Jewitt satellites, characterized by large, highly eccentric and/or inclined orbits that are distinct from the nearly circular, uninclined orbits of the regular satellites. This difference can be traced directly to different

Jewitt, David C.

173

Which Transport Protocol for Hybrid Terrestrial and Satellite Systems?

  Physics Websites

Summary: Which Transport Protocol for Hybrid Terrestrial and Satellite Systems? Ihsane Tou1,2 , Pascal, 31400, Toulouse, France {firstname.lastname}@{laas|astrium|cnes}.fr, Abstract. Satellite systems. Moreover, the natural broadcasting capacity of satellite networks makes it a good companion to terrestrial

Paris-Sud XI, Université de

174

MULTIPLICITY OF COMPLEX HYPERSURFACE SINGULARITIES, ROUCHE SATELLITES AND ZARISKI'S PROBLEM

  Mathematics Websites

Summary: MULTIPLICITY OF COMPLEX HYPERSURFACE SINGULARITIES, ROUCH´E SATELLITES AND ZARISKI'S PROBLEM singularit´es d'hypersurfaces complexes, satellites de Rouch´e et probl`eme de Zariski. Soient f, g : (Cn , 0 such an inequality a Rouch´e inequality and we say that g is a Rouch´e satellite of f . In Section 3, we apply

Gasparim, Elizabeth

175

THE CROSSING NUMBER OF SATELLITE KNOTS MARC LACKENBY

  Mathematics Websites

Summary: THE CROSSING NUMBER OF SATELLITE KNOTS MARC LACKENBY 1. Introduction One of the most basic are particular cases of satellite knots, which are defined as follows. Let L be a non-trivial knot in the 3-sphere. Then a knot K is a satellite knot with companion knot L if K lies in a regular neighbourhood N

Lackenby, Marc

176

THE CROSSING NUMBER OF SATELLITE KNOTS MARC LACKENBY

  Mathematics Websites

Summary: THE CROSSING NUMBER OF SATELLITE KNOTS MARC LACKENBY 1. Introduction One of the most basic ). Connected sums are particular cases of satellite knots, which are defined as follows. Let L be a non­trivial knot in the 3­sphere. Then a knot K is a satellite knot with companion knot L if K lies in a regular

Lackenby, Marc

177

SATELLITES OF LEGENDRIAN KNOTS AND REPRESENTATIONS OF THE CHEKANOVELIASHBERG

  Mathematics Websites

Summary: SATELLITES OF LEGENDRIAN KNOTS AND REPRESENTATIONS OF THE CHEKANOV­ELIASHBERG ALGEBRA LENHARD NG AND DAN RUTHERFORD Abstract. We study satellites of Legendrian knots in R3 and their relation has finite-dimensional representations if and only if there exist certain rulings of satellites

Ng, Lenny

178

Postgrado en Investigacin Matemtica Knots, satellites and algebra

  Mathematics Websites

Summary: Curso Postgrado en Investigación Matemática Knots, satellites and algebra 20 - 24 de abril de 2009 with invariants of knots. Linking number of curves and use of Seifert surfaces. Construction of satellites. Its relation to other knot invariants and its use in conjunction with satellites. The defining skein

Tradacete, Pedro

179

ighly capable small satellites are commonplace today, but this was-

  Physics Websites

Summary: H ighly capable small satellites are commonplace today, but this was- n't always the case. It wasn't until the late 1980s that modern small satellites came on the scene. This new breed of low-profile, low category? A precise description of small satellites, or "lightsats," as they were also called, was lacking

Rhoads, James

180

2014 AADR Satellite Symposium in Clinical Research Charlotte, North Carolina

  Biology and Medicine Websites

Summary: 2014 AADR Satellite Symposium in Clinical Research Charlotte, North Carolina March 17-19, 2014 in Oral Health Research* will be offering its 2½ day course in clinical research as a Satellite Symposium for this AADR Satellite Symposium is separate from and DOES NOT include access to the AADR Annual Meeting

Klein, Ophir

181

Response of Burrowing Owls to Experimental Removal of Satellite Burrows

  Environmental Sciences and Ecology Websites

Summary: Note Response of Burrowing Owls to Experimental Removal of Satellite Burrows NOELLE A. RONAN,1 of post-emergent nestlings. We experimentally blocked access to burrows within 20 m of nests (satellite burrowing owls to removal of satellite burrows. We compared reproductive performance and nest fidelity

Rosenberg, Daniel K.

182

Evaluation of the Route Optimization for NEMO in Satellite Networks

  Computer Technologies and Information Sciences Websites

Summary: Evaluation of the Route Optimization for NEMO in Satellite Networks Abu Zafar M. Shahriar,atiq}@ou.edu William D. Ivancic Satellite Networks and Architectures Branch NASA Glenn Research Center Cleveland, OH architecture that has been proposed for satellite networks to manage the mobility of Internet Protocol

Atiquzzaman, Mohammed

183

AEROSOL ABSORPTION IN CLOUDY SCENES USING PASSIVE SATELLITE INSTRUMENTS

  Geosciences Websites

Summary: AEROSOL ABSORPTION IN CLOUDY SCENES USING PASSIVE SATELLITE INSTRUMENTS M. de Graaf, L.G. Tilstra, using passive remote sensing by satellites. In passive remote sensing techniques, determination the study of the various direct and indirect aerosol effects on clouds difficult and passive satellite

Graaf, Martin de

184

Mirror Routing for Satellite Networks With Cross-layer Optimization

  Computer Technologies and Information Sciences Websites

Summary: have been proposed for routing in the Low Earth Orbit (LEO) satellite networks. The multi-layeredMirror Routing for Satellite Networks With Cross-layer Optimization Zhijiang Chang, Georgi routing ap- proaches are envisioned as promising because they use Middle Earth Orbit (MEO) satellite

Kuzmanov, Georgi

185

Ris-R-1298(EN) Validation of Satellite SAR Offshore

  Multidisciplinary Databases and Resources Websites

Summary: Risø-R-1298(EN) Validation of Satellite SAR Offshore Wind Speed Maps to In-Situ Data, Microscale- cision and accuracy of the satellite-derived ERS-2 SAR wind products in off- shore regions. The overall project goal is to develop a method for utilizing the satellite wind speed maps for offshore wind


186

International Symposium on Formal Methods 2012 Autonomy in Satellite Systems

  Engineering Websites

Summary: of the satellite the orbit is uniquely defined · Fixing an orbit o, the angular speed (v) is given by: · Orbital currently in orbit: 3,000 · Speed of a satellite in Geostationary Orbit ~ 11,000 Kmph · Radio delay in an elliptical 2D orbit in a 3D space · Given the mass of the Earth, satellite, and the position and velocity

Liberzon, Daniel

187

Runoff estimation using satellite altimetry, GRACE and least squares prediction

  Geosciences Websites

Summary: Runoff estimation using satellite altimetry, GRACE and least squares prediction M. J. Tourian1 , R Runoff estimation using satellite altimetry, GRACE and least squares predic #12;Problem P - R - ETa = dM dt M. J. Tourian1, R. Thor1, J. Riegger2, Nico Sneeuw1 Runoff estimation using satellite altimetry

Stuttgart, Universität

188

On the Life and Death of Satellite Haloes

  Astrophysics (arXiv)

Summary: We study the evolution of dark matter satellites orbiting inside more massive haloes using semi-analytical tools coupled with high-resolution N-Body simulations. We select initial satellite sizes, masses, orbital energies, and eccentricities as predicted by hierarchical models of structure formation. Both the satellite and the main halo are described by a Navarro, Frenk & White density profile with various concentrations.

Giuliano Taffoni; Lucio Mayer; Monica Colpi; Fabio Governato
2003-01-14

189

Performance Modelling of TCP Enhancements in Terrestrial-Satellite Hybrid

  Engineering Websites

Summary: : Forward Acknowledgement LEO : Low Earth Orbit GEO : Geosynchronous Orbit TCP : Transport Control Protocol) to provision for new data services via terrestrial-satellite hybrid networks based on a constellation of LEO-way propagation is ½¼ ½¼¼ ms for LEO satellite and ¾ ¼ ms for GEO satellite) and significant packet losses

Roy, Sumit

190

Optimization of Multiple Continuous Queries over Streaming Satellite Data

  Computer Technologies and Information Sciences Websites

Summary: of California at Davis gertz@cs.ucdavis.edu ABSTRACT Remotely sensed data, in particular satellite imagery, play for remotely sensed data, in par- ticular satellite imagery, in environmental applications and models [8Optimization of Multiple Continuous Queries over Streaming Satellite Data Quinn Hart Cal

Gertz, Michael

191

Measurement and Analysis of Traffic in a Hybrid Satellite-

  Computer Technologies and Information Sciences Websites

Summary: Measurement and Analysis of Traffic in a Hybrid Satellite- Terrestrial Network Qing (Kenny) Shao University #12;April 8, 2004 Measurement and Analysis of Traffic in a Hybrid Satellite-Terrestrial Network 2 References #12;April 8, 2004 Measurement and Analysis of Traffic in a Hybrid Satellite-Terrestrial Network 3

Trajkovic, Ljiljana

192

Satellite Communications David Hart, dhart@cis.ohio-state.edu

  Computer Technologies and Information Sciences Websites

Summary: : The Satellite The satellite itself is also known as the space segment, and is composed of three separate units includes the receiving antenna to pick-up signals from the ground station, a broad band receiver, an input of a telecom satellite, the primary task is to receive signals from a ground station and send them down

Jain, Raj

193

SCALABLE AND ROBUST RELIABLE MULTICAST FOR SATELLITE NETWORKS Kyriakos Manousakis

  Engineering Websites

Summary: Center for Satellite and Hybrid Communication Networks University of Maryland, College Park College Park efficiently. One way of accomplishing that is by using multicast communication between the satellite1 SCALABLE AND ROBUST RELIABLE MULTICAST FOR SATELLITE NETWORKS Kyriakos Manousakis John S. Baras

Baras, John S.

194

GROUP SIZE ESTIMATION FOR HYBRID SATELLITE/TERRESTRIAL RELIABLE

  Computer Technologies and Information Sciences Websites

Summary: hop. Satellite communications seem too expensive at first sight. Neverthe- less, in the context updates. Satellite communications are prone to transmission errors (due to atmo- spheric perturbations the satellite communication) grows. Consequently, the pro- posed approach consists of transmitting data via

Mailhes, Corinne

195

SATELLITE ATM NETWORK ARCHITECTURAL CONSIDERATIONS AND TCP IP PERFORMANCE1

  Computer Technologies and Information Sciences Websites

Summary: technology and Ka-Band satellite communications systems will lead to a vast array of opportunities for new in satellite communications exhibit an increased emphasis on new services as opposed to point-to-point data ATM networking is due to the several advantages o ered by satellite communications technology 3, 8

Jain, Raj

196

WDM Polymer Substrate Mode Photonic Interconnects for Satellite Communications

  Engineering Websites

Summary: WDM Polymer Substrate Mode Photonic Interconnects for Satellite Communications Jian Liu Polar is an enabling technology for future satellite communications to increase capacity ofbandwidth and network-3]. Compared with RF satellite communications, they use much smaller antenna aperture size and consume less

Chen, Ray

197

Programmable Active Networking supporting Next Generation Multimedia Services in Satellite Networks

  Computer Technologies and Information Sciences Websites

Summary: 1 Programmable Active Networking supporting Next Generation Multimedia Services in Satellite the space segment of satellite networks could take benefit. The first commercial regenerative satellite routing functionality will become available. However, from the design of these satellite systems

Bhatti, Saleem N.

198

Hundreds of Milky Way Satellites? Luminosity Bias in the Satellite Luminosity Function

  Astrophysics (arXiv)

Summary: We correct the observed Milky Way satellite luminosity function for luminosity bias using published completeness limits for the Sloan Digital Sky Survey DR5. Assuming that the spatial distribution of Milky Way satellites tracks the subhalos found in the Via Lactea LCDM N-body simulation, we show that there should be between ~300 and ~600 satellites within 400 kpc of the Sun that are brighter than the faintest known dwarf galaxies, and that there may be as many as ~ 1000, depending on assumptions. By taking into account completeness limits, we show that the radial distribution of known Milky Way dwarfs is consistent with our assumption that the full satellite population tracks that of subhalos. These results alleviate the primary worries associated with the so-called missing satellites problem in CDM. We show that future, deep wide-field surveys such as SkyMapper, the Dark Energy Survey (DES), PanSTARRS, and the Large Synoptic Survey Telescope (LSST) will deliver a complete census of ultra-faint dwarf satellites out to the Milky Way virial radius, offer new limits on the free-streaming scale of dark matter, and provide unprecedented constraints on the low-luminosity threshold of galaxy formation.

Erik J. Tollerud; James S. Bullock; Louis E. Strigari; Beth Willman
2008-10-08

199

Poster Abstract: Satellite Based Wireless Sensor Networks Global Scale Sensing with Nano-and Pico-Satellites

  Computer Technologies and Information Sciences Websites

Summary: Poster Abstract: Satellite Based Wireless Sensor Networks ­ Global Scale Sensing with Nano- and Pico-Satellites Walter Colitti Vrije Universiteit Brussel ETRO Dept. Pleinlaan 2, B-1050 Brussels systems of small sensor-equipped satellites improve the cost efficiency and the missions' performance

Dunkels, Adam

200

Search for Unknown Dark Matter Satellites of the Milky Way

  HEP - Phenomenology (arXiv)

Summary: We present a search for Galactic dark matter (DM) satellites using the Large Area Telescope (LAT). N-body simulations based on the Lambda-CDM model of cosmology predict a large number of as yet unobserved Galactic DM satellites. These satellites could potentially produce gamma rays through the self-annihilation of DM particles. Some DM satellites are expected to have hard gamma-ray spectra, finite angular extents, and a lack of counterparts at other wavelengths. We searched for LAT sources with these characteristics. We found no candidate DM satellites matching these criteria in one year of LAT data and interpreted this result in the context of N-body simulations.

Alex Drlica-Wagner; Ping Wang; Elliott Bloom; Louis Strigari; for the Fermi-LAT Collaboration
2011-11-14

201

A new spin on disks of satellite galaxies

  CERN Preprints

Summary: We investigate the angular and kinematic distributions of satellite galaxies around a large sample of bright isolated primaries in the spectroscopic and photometric catalogues of the Sloan Digital Sky Survey (SDSS). We detect significant anisotropy in the spatial distribution of satellites. To test whether this anisotropy could be related to the rotating disks of satellites recently found by Ibata et al. in a sample of SDSS galaxies, we repeat and extend their analysis. Ibata et al. found an excess of satellites on opposite sides of their primaries having anticorrelated radial velocities. We find that this excess is sensitive to small changes in the sample selection criteria which can greatly reduce its significance. In addition, we find no evidence for correspondingly correlated velocities for satellites observed on the same side of their primaries, which would be expected for rotating disks of satellites. We conclude that the detection of coherent rotation in the satellite population in current observationa...

Cautun, Marius; Frenk, Carlos S; Sawala, Till
2014-01-01

202

Sequoia 2000 Metadata Schema For Satellite Images

  CiteSeer

Summary: Sequoia 2000 schema development is based on emerging geospatial standards to accelerate development and facilitate data exchange. This paper focuses on the metadata schema for digital satellite images. We examine how satellite metadata are defined, used, and maintained. We discuss the geospatial standards we are using, and describe a SQL prototype that is based on the Spatial Archive and Interchange Format (SAIF) standard and implemented in the Illustra object-relational database. 1 Introduction The Sequoia 2000 project is developing a computing environment to support global change research, involving large volumes of complex data in many formats [1,2]. 1 The design goals for the database schema that manages these data include: ffl Develop a database schema library composed of user-defined types and SQL templates that support earth science data. A researcher uses these building blocks to create a database schema for a specific application. ffl Include enough metadata so files can b...

Jean T. Anderson; Michael Stonebraker
2000-01-01

203

Satellites in Discs: Regulating the Accretion Luminosity

  Astrophysics (arXiv)

Summary: We demonstrate, using a simple analytic model, that the presence of a massive satellite can globally modify the structure and emission properties of an accretion disc to which it is tidally coupled. We show, using two levels of numerical approximation, that the analytic model gives reasonable results. The results are applicable to two astrophysical situations. In the case of an active galactic nucleus, we consider the case of a $\\sim 10^3\\Msun$ compact companion to the central black-hole and show that it could modulate the emitted spectrum on a timescale of $\\sim10^5$ years. In the case of a T Tauri accretion disc, a satellite such as a sub-dwarf or giant planet could modify the disc spectral energy distribution over a substantial fraction of the T Tauri star lifetime.

Dave Syer; Cathie Clarke
1995-05-04

204

Plato for information mining in satellite imagery

  CiteSeer

Summary: Satellite images are numerous and weakly exploited: it is urgent to develop an efficient and fast indexing/retrieval system to easy their access. Content-Based Image Retrieval systems (CBIR) are known to provide an efficient framework. We thus propose to associate a CBIR approach with text-based queries to adapt to these big (12000×12000 pixels) and semantically rich images. The presented system relies on a multimedia data mining system called PLATO able to adapt to any kind of multimedia data. Moreover state-of-the-art relevance feedback strategy is introduced to provide interactive learning and auto annotation. The experimental results show that the proposed approach greatly reduces the user’s effort of interpreting satellite images.

Soufiane Rital; Mihai Costache; Marine Campedel
2008-01-01

205

Dark matter substructure and dwarf galactic satellites

  CERN Preprints

Summary: A decade ago cosmological simulations of increasingly higher resolution were used to demonstrate that virialized regions of Cold Dark Matter (CDM) halos are filled with a multitude of dense, gravitationally-bound clumps. These dark matter subhalos are central regions of halos that survived strong gravitational tidal forces and dynamical friction during the hierarchical sequence of merging and accretion via which the CDM halos form. Comparisons with observations revealed that there is a glaring discrepancy between abundance of subhalos and luminous satellites of the Milky Way and Andromeda as a function of their circular velocity or bound mass within a fixed aperture. This large discrepancy, which became known as the ``substructure'' or the ``missing satellites'' problem, begs for an explanation. In this paper I review the progress made during the last several years both in quantifying the problem and in exploring possible scenarios in which it could be accommodated and explained in the context of galaxy forma...

Kravtsov, Andrey V
2009-01-01

206

Efficient statistical classification of satellite measurements

  CERN Preprints

Summary: Supervised statistical classification is a vital tool for satellite image processing. It is useful not only when a discrete result, such as feature extraction or surface type, is required, but also for continuum retrievals by dividing the quantity of interest into discrete ranges. Because of the high resolution of modern satellite instruments and because of the requirement for real-time processing, any algorithm has to be fast to be useful. Here we describe an algorithm based on kernel estimation called Adaptive Gaussian Filtering that incorporates several innovations to produce superior efficiency as compared to three other popular methods: k-nearest-neighbour (KNN), Learning Vector Quantization (LVQ) and Support Vector Machines (SVM). This efficiency is gained with no compromises: accuracy is maintained, while estimates of the conditional probabilities are returned. These are useful not only to gauge the accuracy of an estimate in the absence of its true value, but also to re-calibrate a retrieved image and...

Mills, Peter
2012-01-01

207

Satellite streamfunction analysis for the California current

  Texas A&M University - TxSpace

Summary: resolution radiometers (AVHRR) measure radiation in two visible and three infrared spectral bands twice a day for given geographic location. These infrared radiometers measure the radiation of a portion of the upper millimeter of the ocean surface... with visible bands yield estimates of pigment concentration in the surface layer. Like infrared radiometers, the application of CZCS images to oceanic problems is limited by atmospheric water vapor. C. Satellite Mesoscale Studies The AVHRR is a useful...

Arango, Hernan Guillermo
1987-01-01

208

Photometric Survey of the Irregular Satellites

  Astrophysics (arXiv)

Summary: We present BVRI colors of 13 Jovian and 8 Saturnian irregular satellites obtained with the 2.56m Nordic Optical Telescope on La Palma, the 6.5m Magellan Baade Telescope on La Campanas, and the 6m MMT on Mt. Hopkins. The observations were performed between December 2001 to March 2002. Nearly all of the known irregular satellites can be divided into two distinct classes based on their colors. One, the grey color class, has the similar colors to the C-type asteroid, and the other, the light red color class, has colors similar to P/D-type asteroids. We also find at least one object, the Jovian irregular J XXIII Kalyke, that has colors similar to the red colored Centaurs/TNOs, although its classification is unsecure. We also find that there is a correlation between the physical properties and dynamical properties of the irregular satellites. Most of the dynamical clusters have homogeneous colors, which points to single homogeneous progenitors being cratered or fragmented as the source of each individual cluster. The heterogeneous colored clusters are most easily explained by assuming that there are several dynamical clusters in the area, rather than just one.

Tommy Grav; Matthew J. Holman; Brett Gladman; Kaare Aksnes
2003-01-02

209

Galaxy Satellites and the Weak Equivalence Principle

  CERN Preprints

Summary: Numerical simulations of the effect of a long-range scalar interaction (LRSI) acting only on nonbaryonic dark matter, with strength comparable to gravity, show patterns of disruption of satellites that can agree with what is seen in the Milky Way. This includes the symmetric Sagittarius stellar stream. The exception presented here to the Kesden and Kamionkowski demonstration that an LRSI tends to produce distinctly asymmetric streams follows if the LRSI is strong enough to separate the stars from the dark matter before tidal disruption of the stellar component, and if stars dominate the mass in the luminous part of the satellite. It requires that the Sgr galaxy now contains little dark matter, which may be consistent with the Sgr stellar velocity dispersion, for in the simulation the dispersion at pericenter exceeds virial. We present other examples of simulations in which a strong LRSI produces satellites with large mass-to-light ratio, as in Draco, or free streams of stars, which might be compared to ``orph...

Keselman, J A; Peebles, P J E
2009-01-01

210

Galaxy Satellites and the Weak Equivalence Principle

  General Relativity & Quantum Cosmology (arXiv)

Summary: Numerical simulations of the effect of a long-range scalar interaction (LRSI) acting only on nonbaryonic dark matter, with strength comparable to gravity, show patterns of disruption of satellites that can agree with what is seen in the Milky Way. This includes the symmetric Sagittarius stellar stream. The exception presented here to the Kesden and Kamionkowski demonstration that an LRSI tends to produce distinctly asymmetric streams follows if the LRSI is strong enough to separate the stars from the dark matter before tidal disruption of the stellar component, and if stars dominate the mass in the luminous part of the satellite. It requires that the Sgr galaxy now contains little dark matter, which may be consistent with the Sgr stellar velocity dispersion, for in the simulation the dispersion at pericenter exceeds virial. We present other examples of simulations in which a strong LRSI produces satellites with large mass-to-light ratio, as in Draco, or free streams of stars, which might be compared to "orphan" streams.

J. A. Keselman; A. Nusser; P. J. E. Peebles
2009-08-29

211

The reionization of galactic satellite populations

  CERN Preprints

Summary: We use high resolution simulations of the formation of the local group post-processed by a radiative transfer code for UV photons, to investigate the reionization of the satellite populations of an isolated Milky Way-M31 galaxy pair in a variety of scenarios. We use an improved version of ATON which includes a simple recipe for radiative feedback. In our baseline models, reionization is initiated by low mass, radiatively regulated haloes at high redshift, until more massive haloes appear, which then dominate and complete the reionization process. We investigate the relation between reionization history and present-day positions of the satellite population. We find that the average reionization redshift (zr) of satellites is higher near galaxy centers (MW and M31). This is due to the inside-out reionization patterns imprinted by massive haloes within the progenitor during the EoR, which end up forming the center of the galaxy. Thanks to incomplete dynamical mixing during galaxy assembly, these early patterns s...

Ocvirk, P; Aubert, D; Knebe, A; Libeskind, N; Chardin, J; Gottlöber, S; Yepes, G; Hoffman, Y
2014-01-01

212

A Region Void of Irregular Satellites Around Jupiter

  CERN Preprints

Summary: An interesting feature of the giant planets of our solar system is the existence of regions around these objects where no irregular satellites are observed. Surveys have shown that, around Jupiter, such a region extends from the outermost regular satellite Callisto, to the vicinity of Themisto, the innermost irregular satellite. To understand the reason for the existence of such a satellite-void region, we have studied the dynamical evolution of Jovian irregulars by numerically integrating the orbits of several hundred test particles, distributed in a region between 30 and 80 Jupiter-radii, for different values of their semimajor axes, orbital eccentricities, and inclinations. As expected, our simulations indicate that objects in or close to the influence zones of the Galilean satellites become unstable because of interactions with Ganymede and Callisto. However, these perturbations cannot account for the lack of irregular satellites in the entire region between Callisto and Themisto. It is suggested that at ...

Haghighipour, N
2008-01-01

213

Some Implications of the Anisotropic Distribution of Satellite Galaxies

  Astrophysics (arXiv)

Summary: We examine a possible connection between the anisotropic distribution of satellite galaxies around giant spiral galaxies and the evolution of satellite systems. The observed polar anisotropy (Zaritsky et al.1997) is either imprinted by initial conditions or develops from an initially symmetric distribution. We attempt to discriminate between these two possibilities by exploring the implications of the latter one. From the observed distribution of satellite galaxies relative to the primary galaxy's disk, we derive constrains on the orbital inclinations of the current satellite population. Using this derived inclination limit and assuming that the initial population had no preferred orbital inclination, we estimate the size of the hypothesized original population. We find that our best-fit models imply a population of destroyed (or inhibited) satellites whose combined luminosity (assuming the same M/L as for the observed satellites) is between 18% and 103% of the current disk luminosity.

Dennis Zaritsky; Anthony H. Gonzalez
1999-08-17

214

LARES succesfully launched in orbit: satellite and mission description

  CERN Preprints

Summary: On February 13th 2012, the LARES satellite of the Italian Space Agency (ASI) was launched into orbit with the qualification flight of the new VEGA launcher of the European Space Agency (ESA). The payload was released very accurately in the nominal orbit. The name LARES means LAser RElativity Satellite and summarises the objective of the mission and some characteristics of the satellite. It is, in fact, a mission designed to test Einstein's General Relativity Theory (specifically 'frame dragging' and Lense-Thirring effect). The satellite is passive and covered with optical retroreflectors that send back laser pulses to the emitting ground station. This allows accurate positioning of the satellite, which is important for measuring the very small deviations from Galilei-Newton's laws. In 2008, ASI selected the prime industrial contractor for the LARES system with a heavy involvement of the universities in all phases of the programme, from the design to the construction and testing of the satellite and separation...

Paolozzi, Antonio
2013-01-01

215

Color Dependence in the Spatial Distribution of Satellite Galaxies

  Astrophysics (arXiv)

Summary: We explore the color dependence of the radial profile of satellite galaxies around isolated parent galaxies. Samples of potential satellites selected from large galaxy redshift surveys are significantly contaminated by interlopers -- objects not bound to the parent galaxy. We use the Sloan Digital Sky Survey to estimate the interloper fraction in samples of candidate satellite galaxies. We show that samples of red and blue satellites have different interloper populations: a larger fraction of blue galaxies are likely to be interlopers compared to red galaxies. Both with and without interloper subtraction, the radial profile of blue satellites is significantly shallower than that of red satellites. In addition, while red and blue primaries have different interloper fractions, the slope of the corrected radial profiles are consistent after interloper correction. We discuss the implications of these results for galaxy formation models.

Jacqueline Chen
2008-04-08

216

From Tidal Dwarf Galaxies to Satellite Galaxies

  Astrophysics (arXiv)

Summary: Cosmological models have granted dwarf galaxies a key role: their properties constrain the distribution of dark matter and the physical evolution of their hosts. There is increasing evidence that objects with masses of dwarf galaxies form in the tidal tails of colliding galaxies and speculations that they could become satellite-like galaxies around their progenitors and thus be cosmologically important. Yet, whether these "Tidal Dwarf Galaxies" (TDGs) candidates are really long-lived and not only present in young interacting systems is still an open question to which numerical simulations may give answers. We present a set of 96 simulations of colliding galaxies with various mass ratios and encounter geometries, and statistically study the evolution of their TDG candidates. Among the 593 substructures initially identified in tidal tails, about 75% fall back onto their progenitor or are disrupted in a few 10^8 years. The remaining 25% become long-lived bound objects that typically survive more than 2Gyr with masses above 10^8 M_sun. These long-lived, satellite-like objects, are found to form in the outer most regions of the tidal tails. We infer several basic properties that dwarf galaxies should meet to have a tidal origin and apply these criteria to the Local Group dwarfs. We also find that the presence of TDGs would foster the anisotropy observed in the distribution of satellite galaxies around their host. Identifying the conditions required for interacting systems to form long-lived tidal dwarfs, we roughly estimate their contribution to the overall population of dwarfs. We conclude that a small but significant fraction of them - typically a few percent, and possibly more in dense environments or around early-type galaxies - could be of tidal origin.

F. Bournaud; P. -A. Duc
2006-05-15

217

The Anisotropic Distribution of Galactic Satellites

  Astrophysics (arXiv)

Summary: We present a study of the spatial distribution of subhalos in galactic dark matter halos using dissipationless cosmological simulations of the concordance LCDM model. We find that subhalos are distributed anisotropically and are preferentially located along the major axes of the triaxial mass distributions of their hosts. The Kolmogorov-Smirnov probability for drawing our simulated subhalo sample from an isotropic distribution is P_KS \\simeq 1.5 \\times 10^{-4}. An isotropic distribution of subhalos is thus not the correct null hypothesis for testing the CDM paradigm. The nearly planar distribution of observed Milky Way (MW) satellites is marginally consistent (probability \\simeq 0.02) with being drawn randomly from the subhalo distribution in our simulations. Furthermore, if we select the subhalos likely to be luminous, we find a distribution that is consistent with the observed MW satellites. In fact, we show that subsamples of the subhalo population with a centrally-concentrated radial distribution, similar to that of the MW dwarfs, typically exhibit a comparable degree of planarity. We explore the origin of the observed subhalo anisotropy and conclude that it is likely due to (1) preferential accretion of subhalos along filaments, often closely aligned with the major axis of the host halo, and (2) evolution of satellite orbits within the prolate, triaxial potentials typical of CDM halos. Agreement between predictions and observations requires the major axis of the outer dark matter halo of the Milky Way to be nearly perpendicular to the disk. We discuss possible observational tests of such disk-halo alignment with current large galaxy surveys.

Andrew R. Zentner; Andrey V. Kravtsov; Oleg Y. Gnedin; Anatoly A. Klypin
2005-04-23

218

Andromeda and its satellites - a kinematic perspective

  CERN Preprints

Summary: Using spectroscopic data taken with Keck II DEIMOS by the Z-PAndAS team in the Andromeda-Triangulum region, I present a comparison of the disc and satellite systems of Andromeda with those of our own Galaxy. I discuss the observed discrepancies between the masses and scale radii of Andromeda dwarf spheroidal galaxies of a given luminosity with those of the Milky Way. I also also present an analysis of the newly discovered M31 thick disc, which is measured to be hotter, more extended and thicker than that seen in the Milky Way.

Collins, Michelle L M; Chapman, Scott C
2012-01-01

219

Spatial and kinematic alignments between central and satellite halos

  Astrophysics (arXiv)

Summary: Based on a cosmological N-body simulation we analyze spatial and kinematic alignments of satellite halos within six times the virial radius of group size host halos (Rvir). We measure three different types of spatial alignment: halo alignment between the orientation of the group central substructure (GCS) and the distribution of its satellites, radial alignment between the orientation of a satellite and the direction towards its GCS, and direct alignment between the orientation of the GCS and that of its satellites. In analogy we use the directions of satellite velocities and probe three further types of alignment: the radial velocity alignment between the satellite velocity and connecting line between satellite and GCS, the halo velocity alignment between the orientation of the GCS and satellite velocities and the auto velocity alignment between the satellites orientations and their velocities. We find that satellites are preferentially located along the major axis of the GCS within at least 6 Rvir (the range probed here). Furthermore, satellites preferentially point towards the GCS. The most pronounced signal is detected on small scales but a detectable signal extends out to 6 Rvir. The direct alignment signal is weaker, however a systematic trend is visible at distances < 2 Rvir. All velocity alignments are highly significant on small scales. Our results suggest that the halo alignment reflects the filamentary large scale structure which extends far beyond the virial radii of the groups. In contrast, the main contribution to the radial alignment arises from the adjustment of the satellite orientations in the group tidal field. The projected data reveal good agreement with recent results derived from large galaxy surveys. (abridged)

A. Faltenbacher; Y. P. Jing; Cheng Li; Shude Mao; H. J. Mo; Anna Pasquali; Frank C. van den Bosch
2007-12-18

220

Black rain: The burial of the Galilean satellites in irregular satellite debris William F. Bottke a,

  Geosciences Websites

Summary: satellites are dormant comet-like bodies that reside on distant prograde and retrograde orbits around-called Nice model. According to this scenario, giant planet migration scattered tens of Earth masses of comet-like bodies throughout the Solar System, with some comets finding themselves near giant planets experiencing

Bottke, William F.

221

Satellite Data Assimilation forSatellite Data Assimilation for Naval Undersea CapabilityNaval Undersea Capability

  Geosciences Websites

Summary: of satellite altimeters necessary to ensure maximum weapon effectiveness · To determine the point at which additional altimeter input no longer increases weapon effectiveness #12;Modular Ocean Data Assimilation for quantifying the effect on weapon presets #12;Environmental Fields · 2 MODAS data fields ­ one with assimilated

Chu, Peter C.

222

The dynamics of satellite disruption in cold dark matter haloes

  Astrophysics (arXiv)

Summary: We investigate the physical mechanisms of tidal heating and satellite disruption in cold dark matter host haloes using N-body simulations based on cosmological initial conditions. We show the importance of resonant shocks and resonant torques with the host halo to satellite heating. A resonant shock (torque) couples the radial (tangential) motion of a satellite in its orbit to its phase space. For a satellite on a circular orbit, an ILR-like resonance dominates the heating and this heating results in continuous satellite mass loss. We estimate the requirements for simulations to achieve these dynamics using perturbation theory. Both resonant shocks and resonant torques affect satellites on eccentric orbits. We demonstrate that satellite mass loss is an outside-in process in energy space; a satellite's stars and gas are thus protected by their own halo against tidal stripping. We simulate the evolution of a halo similar to the Large Magellanic Cloud (LMC) in our Galactic dark matter halo and conclude that the LMC stars have not yet been stripped. Finally, we present a simple algorithm for estimating the evolution of satellite mass that includes both shock heating and resonant torques.

Jun-Hwan Choi; Martin D. Weinberg; Neal Katz
2009-08-17

223

Adaptive Beamforming in Mobile, Massively Multiuser Satellite Communications: A System

  Engineering Websites

Summary: frequency spectrum. In terrestrial communications, high throughput mass- market communications are enabled spec- trum to mobile satellite systems (MSS) by introducing the adaptive beamforming approaches (also

Gesbert, David

224

Notes to Saturn satellites Ijiraq and Kiviuq mutual close encounters

  Astrophysics (arXiv)

Summary: The problem of origin of outer irregular satellites of large planets is considered. The capture way of their origin most probable, however there is not detail theory. There are a number of irregular satellites, discovered in recent time. It gives an ability to investigate the statistics of orbital interaction and try to reconstruct real collision history of these objects We restrict this consideration by pair of orbits with close elements: Kiviuq and Ijiraq and determine period of close encounters between this satellites. It may be considered as a first step on road to the construction of theory of origin of the abundant class of irregular satellites.

A. E. Rosaev
2006-02-01

225

Designing Satellite Communication Networks by Zero-One Quadratic Programming

  MIT - DSpace

Summary: In satellite communications networks, distinctive facilities called homing stations perform special transmission functions. Local demand nodes clustered around each homing station communicate with each other via a local ...

Helme, Marcia P.

226

The subhalo - satellite connection and the fate of disrupted satellite galaxies

  Astrophysics (arXiv)

Summary: In the standard paradigm, satellite galaxies are believed to be associated with the population of dark matter subhalos. In this paper, we use the conditional stellar mass functions of {\\it satellite galaxies} obtained from a large galaxy group catalogue together with models of the subhalo mass functions to explore the fraction and fate of stripped stars from satellites in galaxy groups and clusters of different masses. The majority of the stripped stars in massive halos are predicted to end up as intra-cluster stars, and the predicted amounts of the intra-cluster component as a function of the velocity dispersion of galaxy system match well the observational results obtained by Gonzalez et al. (2007). The fraction of the mass in the stripped stars to that remain bound in the central and satellite galaxies is the highest ($\\sim 40%$ of the total stellar mass) in halos with masses $M_h\\sim 10^{14}\\msunh$. If all these stars end up in the intra-cluster component (Max), or maximum of them are accreted into the central galaxy (Min), then we can predict that a maximum $\\sim 19%$ and a minimum $\\sim 5%$ of the total stars in the whole universe are in terms of the diffused intra-cluster component. In the former case, in massive halos with $M_h \\sim 10^{15} \\msunh$, the stellar mass of the intra-cluster component is roughly 6 times as large as that of the central galaxy. This factor decreases to $\\sim 2$, 1 and 0.1 in halos with $M_h \\sim 10^{14}$, $10^{13}$, and $10^{12} \\msunh$, respectively. The total amount of stars stripped from satellite galaxies is insufficient to build up the central galaxies in halos with masses $\\la 10^{12.5}\\msunh$, and so the quenching of star formation must occur in halos with higher masses. Abridged.

Xiaohu Yang; H. J. Mo; Frank C. van den Bosch
2008-11-14

227

Satellite dynamics on the Laplace surface

  Astrophysics (arXiv)

Summary: The orbital dynamics of most planetary satellites is governed by the quadrupole moment from the equatorial bulge of the host planet and the tidal field from the Sun. On the Laplace surface, the long-term orbital evolution driven by the combined effects of these forces is zero, so that orbits have a fixed orientation and shape. The "classical" Laplace surface is defined for circular orbits, and coincides with the planet's equator at small planetocentric distances and with its orbital plane at large distances. A dissipative circumplanetary disk should settle to this surface, and hence satellites formed from such a disk are likely to orbit in or near the classical Laplace surface. This paper studies the properties of Laplace surfaces. Our principal results are: (i) if the planetary obliquity exceeds 68.875 deg there is a range of semimajor axes in which the classical Laplace surface is unstable; (ii) at some obliquities and planetocentric distances there is a distinct Laplace surface consisting of nested eccentric orbits, which bifurcates from the classical Laplace surface at the point where instability sets in; (iii) there is also a "polar" Laplace surface perpendicular to the line of nodes of the planetary equator on the planetary orbit; (iv) for circular orbits, the polar Laplace surface is stable at small planetocentric distances and unstable at large distances; (v) at the onset of instability this polar Laplace surface bifurcates into two polar Laplace surfaces composed of nested eccentric orbits.

Scott Tremaine; Jihad Touma; Fathi Namouni
2008-09-01

228

Sundman Stability of Natural Planet Satellites

  CERN Preprints

Summary: The stability of the motion of the planet satellites is considered in the model of the general three-body problem (Sun-planet-satellite). "Sundman surfaces" are constructed, by means of which the concept "Sundman stability" is formulated. The comparison of the Sundman stability with the results of Golubev's c2h method and with the Hill's classical stability in the restricted three-body problem is performed. The constructed Sundman stability regions in the plane of the parameters "energy - moment of momentum" coincide with the analogous regions obtained by Golubev's method, with the value (c2h)cr. The construction of the Sundman surfaces in the three-dimensional space of the specially selected coordinates xyR is carried out by means of the exact Sundman inequality in the general three-body problem. The determination of the singular points of surfaces, the regions of the possible motion and Sundman stability analysis are implemented. It is shown that the singular points of the Sundman surfaces in the coordinate...

Lukyanov, L G
2012-01-01

229

Fast object detection for use onboard satellites

  Astrophysics (arXiv)

Summary: We propose an object detection algorithm which is efficient and fast enough to be used in (almost) real time with the limited computer capacities onboard satellites. For stars below the saturation limit of the CCD detectors it is based on a four neighbourhood local maximum criterion in order to find the centre of a stellar image. For saturated stars it is based on the assumption that the image is increasing monotonically towards the centre in the unsaturated part of the image. The algorithm also calculates approximate stellar magnitudes and efficiently rejects most of the cosmics which would otherwise lead to a large number of false detections. The quality of the algorithm was evaluated with the help of a large set of simulated data for the DIVA satellite mission; different assumptions were made for the noise level, and the presence of cosmics or for a variable sky background. We could show that our algorithm fulfills the requirements for DIVA; only in the case of simulated images which included the bright galaxy M31 some fainter stars could not be detected in the galaxy's vicinity. Since stellar images contain large areas without any stars, we propose an additional block-skipping algorithm which can be coded on special-purpose hardware.

Martin Bange; Stefan Jordan; Michael Biermann; Thomas Kaempke; R alf-Dieter Scholz
2003-01-30

230

Satellite dynamics on the Laplace surface

  CERN Preprints

Summary: The orbital dynamics of most planetary satellites is governed by the quadrupole moment from the equatorial bulge of the host planet and the tidal field from the Sun. On the Laplace surface, the long-term orbital evolution driven by the combined effects of these forces is zero, so that orbits have a fixed orientation and shape. The "classical" Laplace surface is defined for circular orbits, and coincides with the planet's equator at small planetocentric distances and with its orbital plane at large distances. A dissipative circumplanetary disk should settle to this surface, and hence satellites formed from such a disk are likely to orbit in or near the classical Laplace surface. This paper studies the properties of Laplace surfaces. Our principal results are: (i) if the planetary obliquity exceeds 68.875 deg there is a range of semimajor axes in which the classical Laplace surface is unstable; (ii) at some obliquities and planetocentric distances there is a distinct Laplace surface consisting of nested eccentr...

Tremaine, Scott; Namouni, Fathi
2008-01-01

231

STRUCTURAL HIGH-RESOLUTION SATELLITE IMAGE INDEXING Gui-Song Xia1

  Physics Websites

Summary: STRUCTURAL HIGH-RESOLUTION SATELLITE IMAGE INDEXING Gui-Song Xia1 , Wen Yang2 , Julie Delon1 , Yann: retrieval and classification, high-resolution satellite image, structure, texture ABSTRACT: Satellite images-resolution satellite images. We suggest a satellite image indexing method relying on topographic maps and a shape

Paris-Sud XI, Université de

232

SEQUOIA 2000 METADATA SCHEMA FOR SATELLITE IMAGES Jean T. Anderson and Michael Stonebraker

  Computer Technologies and Information Sciences Websites

Summary: SEQUOIA 2000 METADATA SCHEMA FOR SATELLITE IMAGES Jean T. Anderson and Michael Stonebraker EECS. This paper focuses on the metadata schema for digital satellite images. We examine how satellite metadata on the metadata schema being developed to manage satellite images. Section 2 looks at satellite data

California at Irvine, University of

233

ORIGINAL PAPER Satellite telemetry reveals post-breeding movements

  Environmental Sciences and Ecology Websites

Summary: ORIGINAL PAPER Satellite telemetry reveals post-breeding movements of Atlantic puffins Fratercula satellite transmitters to the back feathers of five Atlantic puffins Fratercula arctica breeding in Røst of that indicated by all but 1 of the 27 existing ring recoveries of adult puffins from colonies in North Norway

Holberton, Rebecca L.

234

First satellite observations of lower tropospheric ammonia and methanol

  Geosciences Websites

Summary: First satellite observations of lower tropospheric ammonia and methanol Reinhard Beer,1 Mark W products revealed surprisingly strong features attributable to enhanced concentrations of ammonia (NH3. Citation: Beer, R., et al. (2008), First satellite observations of lower tropospheric ammonia and methanol


235

Effects of Rain Attenuation on Satellite Video Transmission

  Computer Technologies and Information Sciences Websites

Summary: Effects of Rain Attenuation on Satellite Video Transmission Yee Hui Lee and Stefan Winkler Nanyang, email: stefan.winkler@adsc.com.sg Abstract--Heavy convective rain events are often experienced] caused by rain or cloud cover. Poor link conditions can lead to signal outage. Satellite service

Winkler, Stefan

236

Lake level variations from satellite radar altimetry with

  Geosciences Websites

Summary: Lake level variations from satellite radar altimetry with retracking of multi-leading edge Shirzad with retracking of multi-leading edge 1 #12;RADAR principle http://www.altimetry.info Lake level variations from duration Lake level variations from satellite radar altimetry with retracking of multi-leading edge 3 #12

Stuttgart, Universität

237

Management and Service Discovery in Satellite and Avionic Networks

  Computer Technologies and Information Sciences Websites

Summary: Communication links transfer data between satellites, un- manned airborne vehicles (UAVs), and devices on the ground. UAVs are used to analyze pollution, relay communications and host a variety of sensors and stor- age nodes. Often, networked platforms (UAVs, and earth or- biting satellites) are deployed

Lockwood, John W.

238

"Globalstar, Iridium and other Satellite-Based Mobile Phone

  Computer Technologies and Information Sciences Websites

Summary: tubes], radio was ­ Primarily broadcast ­ Receivers were fixed locations or automobiles · In the 70's's, satellites were ­ Mostly geosynchronous earth orbit or GEO ­ Invaluable for relay and broadcast of the LEO · Mobile phones have small, omni antenna ­ Could not reach existing GEO satellites ­ Could reach


239

Distributed Geo-rectification of Satellite Images using Grid Computing

  Computer Technologies and Information Sciences Websites

Summary: 1 Distributed Geo-rectification of Satellite Images using Grid Computing Y.M. Teo* , S.C. Tay you don't own for compute-intensive applications. Geo-rectification is a process for correcting of the compute- intensive satellite image geo-rectification problem on a cluster grid. We discuss our approach

Teo, Yong-Meng

240

Indian Regional Navigation Satellites System (IRNSS) is the world's rst

  Engineering Websites

Summary: in all, with three satellites in GEO stationary and four in GEO synchronous orbits (Kibe & Gowrishankar to design, develop and deploy the IRNSS satellites. A brief introduction on the GPS Aided GEO Augmented from Table 1, two new locations are proposed for IRNSS GEO, which coincides with the GSO crossing

Calgary, University of

241

Physical aspects to consider in radiometric calibration of satellite images

  CERN Preprints

Summary: It does a revision about the physical principles involved in digital processing of satellite images, more specifically in radiometric calibration of them. It shows a conceptual description of the interaction between radiation and atmosphere and radiation and soil in order to help the reader understand in more detail which means the information contained in satellite images.

Delgado-Correal, Camilo
2012-01-01

242

Heuristics for Robust Resource Allocation of Satellite Weather Data Processing

  Engineering Websites

Summary: Heuristics for Robust Resource Allocation of Satellite Weather Data Processing on a Heterogeneous--This work considers the satellite data processing portion of a space-based weather monitoring system INTRODUCTION THE space-based weather monitoring system considered in this work consists of two major components

Maciejewski, Anthony A.

243

Title: IKONOS Satellite Image of North York, Ontario Data Creator /

  Computer Technologies and Information Sciences Websites

Summary: Title: IKONOS Satellite Image of North York, Ontario Data Creator / Copyright Owner: Geo: -79.3930 degrees #12;Index Map: N/A Keywords (Place): Toronto, Ontario; North York, Ontario; York University, Ontario Keywords (Subject): Satellite Imagery, Aerial Images Restrictions: Data is licensed


244

Asteroid 2014 OL339: yet another Earth quasi-satellite

  CERN Preprints

Summary: Our planet has one permanently bound satellite -the Moon-, a likely large number of mini-moons or transient irregular natural satellites, and three temporary natural retrograde satellites or quasi-satellites. These quasi-moons -(164207) 2004 GU9, (277810) 2006 FV35 and 2013 LX28- are unbound companions to the Earth. The orbital evolution of quasi-satellites may transform them into temporarily bound satellites of our planet. Here, we study the dynamical evolution of the recently discovered Aten asteroid 2014 OL339 to show that it is currently following a quasi-satellite orbit with respect to the Earth. This episode started at least about 775 yr ago and it will end 165 yr from now. The orbit of this object is quite chaotic and together with 164207 are the most unstable of the known Earth quasi-satellites. This group of minor bodies is, dynamically speaking, very heterogeneous but three of them exhibit Kozai-like dynamics: the argument of perihelion of 164207 oscillates around -90 degrees, the one of 277810 libr...

Marcos, C de la Fuente
2014-01-01

245

Quantifying Offshore Wind Resources from Satellite Wind Maps

  Environmental Sciences and Ecology Websites

Summary: on satellite image pro- cessing and wind power meteorology is combined in the current work. FurthermoreQuantifying Offshore Wind Resources from Satellite Wind Maps: Study Area the North Sea C. B. Hasager*, R. J. Barthelmie, M. B. Christiansen, M. Nielsen and S. C. Pryor, Wind Energy Department, Risø

Pryor, Sara C.

246

OUTER PLANETS' SATELLITES ASTR/GEOL 5800 Planetary Surfaces & Interiors

  Geosciences Websites

Summary: Hyperion 24.5 21.28 0.1042 ~100 chaotic res. Titan Iapetus 59.1 79.3 0.0283 718 1.02 Inc. 15° Uranus.64 Inc. 130° #12;Things to Notice · Jupiter has 4 large (>1500 km) moons, Saturn 1, and Uranus slide). Uranian satellites are denser. · Uranus satellite densities increase (roughly) with distance

Mojzsis, Stephen J.

247

Earthquake Damage Identification using High-Resolution Satellite

  Engineering Websites

Summary: & evaluation · High-resolution satellite imagery · Images from Boumerdes, Algeria · Semi-automated damage, 7:44 pm, Mw 6.8 from neic.usgs.gov #12;Satellite Images · 3 Quickbird images of Boumerdes ­ 22 April requires 64 km2 minimum size #12;Boumerdes 23 May 2003 500 m #12;SW Boumerdes ­ April 02 Buildings, roads

Shinozuka, Masanobu

248

Formation flying control for satellites: anti-windup based approach

  Physics Websites

Summary: . These missions use high precision thrusters as actuators whose capacity appears to be critically low. MoreoverFormation flying control for satellites: anti-windup based approach J. Boada, C. Prieur, S-windup compensator design to the control with high precision for the angular and the linear axes of a satellite

Paris-Sud XI, Université de

249

Monitoring drying up of Urmia lake satellite altimetry

  Geosciences Websites

Summary: Monitoring drying up of Urmia lake with satellite altimetry Sh. Roohi (shirzad Validation Analysis and conclusion Monitoring drying up of Urmia lake with satellite altimetry 1 #12;Introduction Urmia lake Geography Chemistry Ecology Main inflow rivers Monitoring drying up of Urmia lake

Stuttgart, Universität

250

Resonant Thickening of Disks by Small Satellite Galaxies

  Astrophysics (arXiv)

Summary: We study the vertical heating and thickening of galaxy disks due to accretion of small satellites. Our simulations are restricted to axial symmetry, which largely eliminates numerical evolution of the target galaxy but requires the trajectory of the satellite to be along the symmetry axis of the target. We find that direct heating of disk stars by the satellite is not important because the satellite's gravitational perturbation has little power at frequencies resonant with the vertical stellar orbits. The satellite does little damage to the disk until its decaying orbit resonantly excites large-scale disk bending waves. Bending waves can damp through dynamical friction from the halo or internal wave-particle resonances; we find that wave-particle resonances dominate the damping. The principal vertical heating mechanism is therefore dissipation of bending waves at resonances with stellar orbits in the disk. Energy can thus be deposited some distance from the point of impact of the satellite. The net heating from a tightly bound satellite can be substantial, but satellites that are tidally disrupted before they are able to excite bending waves do not thicken the disk.

J. A. Sellwood; Robert W. Nelson; Scott Tremaine
1998-05-12

251

Analysis of billing data from a hybrid satellite network

  Engineering Websites

Summary: operations center Satellite Computer Modem Dial-up ISP Internet TCP-splitting PPP connection IP spoofing PPP Internet service 5 IP spoofing and TCP splitting Each user has 2 IP addresses: dialup IP and satellite IP Data transfer pair for dialup, DSL, or cable modem is: source (user) IP, destination IP Direc

Trajkovic, Ljiljana

252

Adaptive Virtual Queue Random Early Detection in Satellite Networks

  Engineering Websites

Summary: Adaptive Virtual Queue Random Early Detection in Satellite Networks Do Jun Byun and John S. Baras queue random early detection (AVQRED) is proposed to solve the problems, and it is validated using Random Early Detection in Satellite Networks 65 1. The problems that we are trying to solve are not due

Baras, John S.

253

Predicting coral bleaching from satellite retrievals of sea surface

  Geosciences Websites

Summary: Predicting coral bleaching from satellite retrievals of sea surface light and temperature William J NOAA CRW World Bank (Remote Sensing and Bleaching WGs) Australian Research Council Linkage Grant Team development · Testing the algorithm #12;Goal of Project Current satellite-based bleaching algorithms · Based

Kuligowski, Bob

254

Visualization and unsupervised classification of changes in multispectral satellite imagery

  Mathematics Websites

Summary: Visualization and unsupervised classification of changes in multispectral satellite imagery MORTON to visualize and to classify changes in multispectral satellite data. The methods are demonstrated detection (Singh 1989): `The basic premise in using remote sensing data for change detection is that changes


255

Discretized Constrained Attitude Pathfinding and Control for Satellites

  Engineering Websites

Summary: of the vector portion of the quaternion u = control torque signal vpk = unit vector to the kth pixel node wDiscretized Constrained Attitude Pathfinding and Control for Satellites Henri C. Kjellberg and E guidance, navigation, and control algorithm is developed for satellites with three degree-of- freedom

Lightsey, Glenn

256

SLOT ALLOCATION IN A TDMA SATELLITE SYSTEM: SIMULATED

  Computer Technologies and Information Sciences Websites

Summary: the uplink slot as­ signment problem in a multi­spot geostationary satellite. Radio interference impose a multi­spot geostationary satel­ lite system for which a manager assigns satellite TDMA slots to service of a multi­spot TDMA system con­ sists of two phases. In the first radio planning phase, carriers

Touati, Corinne

257

Multidisciplinary Design Optimization Methodology for Distributed Satellite Systems

  CiteSeer

Summary: A multiobjective, multidisciplinary design optimization methodology for mathematically modeling the distributed satellite system (DSS) conceptual design problem as an optimization problem has been developed to advance the state-of-the-art in complex distributed satellite network design. An increasing number of space missions are utilizing DSS architectures

Cyrus D. Jilla; D. Jilla
2004-01-01

258

Retrieval of Atmospheric Composition from the MIPAS Satellite Instrument

  Geosciences Websites

Summary: Retrieval of Atmospheric Composition from the MIPAS Satellite Instrument Alastair Burgess A thesis submitted for the degree of Doctor of Philosophy Michaelmas Term, 2005 Atmospheric, Oceanic and Planetary Physics University of Oxford #12;#12;Retrieval of Atmospheric Composition from the MIPAS Satellite

Oxford, University of

259

Stability of Satellites in Closely Packed Planetary Systems

  CERN Preprints

Summary: We perform numerical integrations of four-body (star, planet, planet, satellite) systems to investigate the stability of satellites in planetary Systems with Tightly-packed Inner Planets (STIPs). We find that the majority of closely-spaced stable two-planet systems can stably support satellites across a range of parameter-space which is only slightly decreased compared to that seen for the single-planet case. In particular, circular prograde satellites remain stable out to $\\sim 0.4 R_H$ (where $R_H$ is the Hill Radius) as opposed to $\\sim 0.5 R_H$ in the single-planet case. A similarly small restriction in the stable parameter-space for retrograde satellites is observed, where planetary close approaches in the range 2.5 to 4.5 mutual Hill radii destabilize most satellites orbits only if $a\\sim 0.65 R_H$. In very close planetary pairs (e.g. the 12:11 resonance) the addition of a satellite frequently destabilizes the entire system, causing extreme close-approaches and the loss of satellites over a range of cir...

Payne, Matthew J; Holman, Matthew J; Perets, Hagai B
2013-01-01

260

Scalable Proportional Allocation of Bandwidth in IP Satellite Networks12

  Computer Technologies and Information Sciences Websites

Summary: December 10, 2002 Abstract--Proposed satellite constellation networks, based on Geostationary Earth Orbit (GEO) satellites, Medium Earth Orbit (MEO), and Low Earth Orbit (LEO) systems, will be required have been filed with FCC [2]. The space segment development has now reached the network layer

Jain, Raj

261

A Region Void of Irregular Satellites Around Jupiter

  Astrophysics (arXiv)

Summary: An interesting feature of the giant planets of our solar system is the existence of regions around these objects where no irregular satellites are observed. Surveys have shown that, around Jupiter, such a region extends from the outermost regular satellite Callisto, to the vicinity of Themisto, the innermost irregular satellite. To understand the reason for the existence of such a satellite-void region, we have studied the dynamical evolution of Jovian irregulars by numerically integrating the orbits of several hundred test particles, distributed in a region between 30 and 80 Jupiter-radii, for different values of their semimajor axes, orbital eccentricities, and inclinations. As expected, our simulations indicate that objects in or close to the influence zones of the Galilean satellites become unstable because of interactions with Ganymede and Callisto. However, these perturbations cannot account for the lack of irregular satellites in the entire region between Callisto and Themisto. It is suggested that at distances between 60 and 80 Jupiter-radii, Ganymede and Callisto may have long-term perturbative effects, which may require the integrations to be extended to times much longer than 10 Myr. The interactions of irregular satellites with protosatellites of Jupiter at the time of the formation of Jovian regulars may also be a destabilizing mechanism in this region. We present the results of our numerical simulations and discuss their applicability to similar satellite void-regions around other giant planets.

N. Haghighipour; D. Jewitt
2008-05-24

262

Jupiter's Outer Satellites and Trojans David C. Jewitt

  Physics Websites

Summary: 12 Jupiter's Outer Satellites and Trojans David C. Jewitt Institute for Astronomy, University Institute 12.1 INTRODUCTION Jupiter's irregular satellites possess large, eccentric and highly inclined and the Trojans (the latter co-orbiting the Sun leading and trailing Jupiter by 60 deg). However, there is reason

Jewitt, David C.

263

Jupiter's Outer Satellites and Trojans David C. Jewitt

  Physics Websites

Summary: 12 Jupiter's Outer Satellites and Trojans David C. Jewitt Institute for Astronomy, University Institute 12.1 INTRODUCTION Jupiter's irregular satellites possess large, eccentric and highly inclined and the Trojans (the latter co-orbiting the Sun leading and trailing Jupiter by 60 ). However, there is reason

Jewitt, David C.

264

An abundant population of small irregular satellites around Jupiter

  Physics Websites

Summary: irregular satellites around Jupiter Scott S. Sheppard & David C. Jewitt Institute for Astronomy, University, refs 6, 7), Uranus (six, ref. 8) and Neptune (three, ref. 9). Because Jupiter is closer than the other the discovery of 23 new irregular satellites of Jupiter, so increasing the total known population to 32

Jewitt, David C.

265

Embedding planning technology into satellite systems David Kortenkamp

  Engineering Websites

Summary: . This paper describes an on-board planning and execution system for satellites that schedules system tasks. Introduction There is an increasing need to develop on-board autonomy for satellite systems, both to increase, threat response, and task execution is a key challenge for these systems. HAMMER integrates an on-board

Kortenkamp, David

266

Network Mobility in Satellite Networks: Architecture and the Protocol

  Computer Technologies and Information Sciences Websites

Summary: for multiple IP-enabled devices onboard a satellite that hands off between ground stations. Network Mo- bility reported in this paper was funded by NASA Grant NNX06AE44G. resulting in the mobility of onboard devices protocols are inefficient for handling the mobility of multiple IP-enabled devices onboard satellites due

Atiquzzaman, Mohammed

267

Phenology of marine phytoplankton from satellite ocean color measurements

  Geosciences Websites

Summary: Phenology of marine phytoplankton from satellite ocean color measurements M. Vargas,1 C. W. Brown,1 of these phenological markers from Generalized Linear Models fit to pentad (five-day) estimates of SeaWiFS chlorophyll. Brown, and M. R. P. Sapiano (2009), Phenology of marine phytoplankton from satellite ocean color

Kuligowski, Bob

268

On-Demand Routing in LEO Satellite Systems Stylianos Karapantazis

  Computer Technologies and Information Sciences Websites

Summary: On-Demand Routing in LEO Satellite Systems Stylianos Karapantazis Aristotle University@auth.gr Abstract--In this paper, a location-assisted on-demand routing (LAOR) protocol for low earth orbit (LEO by the characteristics of LEO satellite systems' topology. The LAOR protocol is assessed for different link-cost metrics

Papapetrou, Evaggelos

269

Lunar CRater Observation and Sensing Satellite Lunar Mystery

  Engineering Websites

Summary: LCROSS Lunar CRater Observation and Sensing Satellite Lunar Mystery Earth's closest neighbor signatures detected in permanently shadowed craters at the lunar poles by NASA's Lunar Prospector exploration beyond low-Earth orbit. The Lunar CRater Observing and Sensing Satellite (LCROSS) mission


270

Cratering Rates on the Galilean Satellites Kevin Zahnle & Luke Dones

  Physics Websites

Summary: Cratering Rates on the Galilean Satellites Kevin Zahnle & Luke Dones NASA Ames Research Center, MS., Boulder CO 80302 Version 2.3 November 23, 1998 Running Title: Cratering Rates on the Galilean Satellites­mail: kzahnle@mail.arc.nasa.gov telephone: (650) 604­0840 fax: (650) 604­6779 1 #12; Cratering Rates

Levison, Harold F.

271

Secure Floating-Point Arithmetic and Private Satellite Collision Analysis

  Mathematics Websites

Summary: Secure Floating-Point Arithmetic and Private Satellite Collision Analysis Liina Kamm1,2 and Jan of a collision between two satellites. For this purpose, we first describe basic floating-point arithmetic pre- serving way, we first provide floating point arithmetic for general multiparty computations


272

NASA ACTS SATELLITE: A DISASTER RECOVERY TEST Dr. Hans Kruse

  Engineering Websites

Summary: NASA ACTS SATELLITE: A DISASTER RECOVERY TEST Dr. Hans Kruse School of Communications Systems In September 1993, NASA launched its long- awaited Advanced Communication Technology (ACTS) satellite. ACTS links. The ACTS Disaster Recovery Project was designed to test the Bank's ability to by

Kruse, Hans

273

Observing Gamma Ray Bursts with the RHESSI satellite , W. Hajdas

  Physics Websites

Summary: Observing Gamma Ray Bursts with the RHESSI satellite Wigger , W. Hajdas a D.M. Smith b G. It NASA Small Explorer satellite designed study hard X­rays and gamma­rays solar flares. addition, lightly Gamma Ray Bursts (GRBs). With of view, RHESSI observes about GRB week, sensitive energy band ranging

Guedel, Manuel

274

From the Atlanta Workshop -Use Satellite Data for Model Evaluation

  Environmental Sciences and Ecology Websites

Summary: Assimilation ­ dries surface Control - Model too cool due to moisture Plan to revisit August 2006 Texas evaluations 1. Clouds ­ Clouds play a major role in photolysis rates , temperature and wet chemistry. Models temperature #12;model (control) vs. satellite retrieval Satellite retrievals (K) model (sat. assim.) vs

Jacob, Daniel J.

275

Luminous Satellites II: Spatial Distribution, Luminosity Function and Cosmic Evolution

  CERN Preprints

Summary: We infer the normalization and the radial and angular distributions of the number density of satellites of massive galaxies ($\\log_{10}[M_{h}^*/M\\odot]>10.5$) between redshifts 0.1 and 0.8 as a function of host stellar mass, redshift, morphology and satellite luminosity. Exploiting the depth and resolution of the COSMOS HST images, we detect satellites up to eight magnitudes fainter than the host galaxies and as close as 0.3 (1.4) arcseconds (kpc). Describing the number density profile of satellite galaxies to be a projected power law such that $P(R)\\propto R^{\\rpower}$, we find $\\rpower=-1.1\\pm 0.3$. We find no dependency of $\\rpower$ on host stellar mass, redshift, morphology or satellite luminosity. Satellites of early-type hosts have angular distributions that are more flattened than the host light profile and are aligned with its major axis. No significant average alignment is detected for satellites of late-type hosts. The number of satellites within a fixed magnitude contrast from a host galaxy is depe...

Nierenberg, A M; Treu, T; Marshall, P J; Fassnacht, C D; Busha, Michael T
2012-01-01

276

INTERDISCIPLINARY SCIENCE AND APPLICATIONS USING SATELLITE RADAR ALTIMETRY

  Engineering Websites

Summary: orbits #12;17-day Repeat Orbits #12;Satellite Flight direction Example of ocean waveform Power #12;MeanINTERDISCIPLINARY SCIENCE AND APPLICATIONS USING SATELLITE RADAR ALTIMETRY C.K. SHUM EE Wave designed for science over deep-ocean Historic & current missions: Seasat (1978), Geosat (1984), ERS-1


277

Bandwidth Allocation for IP Traffic Over Satellite Links

  Computer Technologies and Information Sciences Websites

Summary: provisioning is discussed. Index terms: satellite communications, ground terminals, TCP/IP, QoS, qualityBandwidth Allocation for IP Traffic Over Satellite Links Claude Bélisle, Peter Andreadis, Steve Bernier, François Lévesque, and Michel Barbeau Communications Research Centre Canada 3701 Carling Avenue

Barbeau, Michel

278

On the central configurations of the coorbital satellite problem

  Mathematics Websites

Summary: On the central configurations of the coorbital satellite problem Josep M. Cors 1 Jaume Llibre 2 Merc`e Oll'e 3 Abstract In this communication we study the central configurations of the coorbital satellite problem --also called 1 +n body problem--, that is, we study the central configurations of a large

Politècnica de Catalunya, Universitat

279

A NOVEL DIMENSIONING METHOD FOR HIGH THROUGHPUT SATELLITE DESIGN

  Physics Websites

Summary: A NOVEL DIMENSIONING METHOD FOR HIGH THROUGHPUT SATELLITE DESIGN Dimitri Serrano-Velarde Eutelsat@eutelsat.com Georges Rodriguez-Guisantes TELECOM ParisTech, Communications and Electronics, 46, rue Barrault, 75634 describes a novel methodology for the dimensioning of a Ka-Band high throughput satellite for broadband

Paris-Sud XI, Université de

280

Calculating Change Curves for Multitemporal Satellite Imagery: Mount St. Helens

  Environmental Sciences and Ecology Websites

Summary: Calculating Change Curves for Multitemporal Satellite Imagery: Mount St. Helens 1980­1995 Rick L satellite imagery using change curves. The The recovery of vegetation following the 1980 eruption method of vegetation is one of the most important the greatest rate of cover increase during the study pe- uses

Lawrence, Rick L.

281

ASYNCHRONOUS OPTIMAL MIXED P2P SATELLITE REFUELING STRATEGIES

  Engineering Websites

Summary: AAS 05-474 ASYNCHRONOUS OPTIMAL MIXED P2P SATELLITE REFUELING STRATEGIES Atri Dutta and Panagiotis Tsiotras Abstract In this paper, we study pure peer-to-peer (henceforth abbreviated as P2P) and mixed (combined single-spacecraft and P2P) satellite refueling in circular orbit constellations com- prised

Tsiotras, Panagiotis

282

Motion properties of satellites around external spiral galaxies

  Astrophysics (arXiv)

Summary: We are analyzing a sample of closeby galaxy systems, each comprising a bright isolated spiral and its satellites. We find an excess (56%) of prograde satellites over retrograde, which basically holds for all angular displacements from the primary major axis. Monte Carlo simulations show that interlopers and mixing systems at different distances in the sample should not affect porcentages sensibly.

M. Azzaro; F. Prada; C. M. Gutiérrez
2003-10-17

283

Peer-to-Peer Refueling for Circular Satellite Constellations

  Engineering Websites

Summary: Peer-to-Peer Refueling for Circular Satellite Constellations Haijun Shen and Panagiotis Tsiotras constellation. It is assumed that there is no fuel delivered to the constellation from an external source. Instead, all satellites in the constellation are assumed to be capable of refueling each other (peer

Tsiotras, Panagiotis

284

Satellite Services Rate Schedule Effective March 26, 2014

  Computer Technologies and Information Sciences Websites

Summary: , which is our minimum charge. **Overtime charges are for services provided outside normal operationOutsiderates. ·Uplinkanddownlinkchargeswillincludealltest periods. If UVa Satellite Services needs to book satellite transponder space an additional 20 requirements and services. Costs of these items will be added to total charges or billed separately by other

Acton, Scott

285

On the scarcity of Magellanic Cloud-like satellites

  CERN Preprints

Summary: We have used H alpha narrow-band imaging to search for star-forming satellite galaxies around 143 luminous spiral galaxies, with the goal of quantifying the frequency of occurrence of satellites resembling the Magellanic Clouds, around galaxies comparable to the Milky Way. For two-thirds of the central galaxies, no star-forming satellites are found, down to luminosities and star-formation rates well below those of the Magellanic Clouds. A total of 62 satellites is found, associated with 47 of the central galaxies searched. The R-band magnitude difference between central galaxies and their satellites has a median value of 4.6 mag, and a maximum of 10.2 mag. The mean projected separation of the satellites from their central galaxies is 81 kpc, or 98 kpc for systems beyond 30 Mpc. Thus star-forming satellites are quite rare, and the Milky Way is unusual both for the luminosity and the proximity of its two brightest satellites. We also find that the Clouds themselves are unusual in that they appear to form a boun...

James, Phil A
2010-01-01

286

Testing General Relativity and gravitational physics using the LARES satellite

  General Relativity & Quantum Cosmology (arXiv)

Summary: The discovery of the accelerating expansion of the Universe, thought to be driven by a mysterious form of `dark energy' constituting most of the Universe, has further revived the interest in testing Einstein's theory of General Relativity. At the very foundation of Einstein's theory is the geodesic motion of a small, structureless test-particle. Depending on the physical context, a star, planet or satellite can behave very nearly like a test-particle, so geodesic motion is used to calculate the advance of the perihelion of a planet's orbit, the dynamics of a binary pulsar system and of an Earth orbiting satellite. Verifying geodesic motion is then a test of paramount importance to General Relativity and other theories of fundamental physics. On the basis of the first few months of observations of the recently launched satellite LARES, its orbit shows the best agreement of any satellite with the test-particle motion predicted by General Relativity. That is, after modelling its known non-gravitational perturbations, the LARES orbit shows the smallest deviations from geodesic motion of any artificial satellite. LARES-type satellites can thus be used for accurate measurements and for tests of gravitational and fundamental physics. Already with only a few months of observation, LARES provides smaller scatter in the determination of several low-degree geopotential coefficients (Earth gravitational deviations from sphericity) than available from observations of any other satellite or combination of satellites.

Ignazio Ciufolini; Antonio Paolozzi; Erricos Pavlis; John Ries; Vahe Gurzadyan; Rolf Koenig; Richard Matzner; Roger Penrose; Giampiero Sindoni
2012-11-06

287

SATELLITE TERMINAL QUALITY OF SERVICE MANAGEMENT WITH AQM CONTROL

  Physics Websites

Summary: SATELLITE TERMINAL QUALITY OF SERVICE MANAGEMENT WITH AQM CONTROL Romain Delpoux1,3, Pascal Berthou architecture to satellite sys- tems. In this paper, we consider an architecture compliant with the Sat consists in controlling TCP streams to guarantee trans- mission capacity of UDP packets. The most

Paris-Sud XI, Université de

288

Dark influences: imprints of dark satellites on dwarf galaxies

  CERN Preprints

Summary: In the context of the current $\\Lambda$CDM cosmological model small dark matter haloes are abundant and satellites of dwarf galaxies are expected to be predominantly dark. Since low mass galaxies have smaller baryon fractions interactions with these satellites may leave particularly dramatic imprints. We uncover the influence of the most massive of these dark satellites on disky dwarf galaxies and the possible dynamical and morphological transformations that result from these interactions. We use a suite of carefully set-up, controlled simulations of isolated dwarf galaxies. The primary dwarf galaxies have solely a stellar disk in the dark matter halo and the secundaries are completely devoid of baryons. We vary the disk mass, halo concentration, initial disk thickness and inclination of the satellite orbit. The disky dwarf galaxies are heated and disrupted due to the minor merger event, more extremely for higher satellite over disk mass ratios, and the morphology and kinematics are significantly altered. Mor...

Starkenburg, Tjitske K
2014-01-01

289

Color Dependence in the Spatial Distribution of Satellite Galaxies

  CERN Preprints

Summary: We explore the color dependence of the radial profile of satellite galaxies around isolated parent galaxies. Samples of potential satellites selected from large galaxy redshift surveys are significanctly contaminated by interlopers -- objects not bound to the parent galaxy. Using the Sloan Digital Sky Survey, we show that samples of red and blue satellites have different interloper populations: a larger fraction of blue galaxies are likely to be interlopers compared to red galaxies. Both with and without interloper subtraction, the radial profile of blue satellites is significantly shallower than that of red satellites. In addition, while red and blue primaries have different interloper fractions, the slope of the corrected radial profiles are consistent after interloper correction. We discuss the implications of these results for galaxy formation models.

Chen, Jacqueline
2007-01-01

290

ForPeerReview Multi-sensor Satellite Remote Sensing of Dust Aerosols over

  Geosciences Websites

Summary: ForPeerReview Multi-sensor Satellite Remote Sensing of Dust Aerosols over North Africa during Keywords: GERBILS, Satellite remote Sensing, Aerosols Quarterly Journal of the Royal Meteorological Society #12;ForPeerReview Satellite Remote Sensing during GERBILS

Christopher, Sundar A.

291

THE GLOBAL IMPACT OF SATELLITE-DERIVED POLAR WINDS ON MODEL FORECASTS

  Environmental Sciences and Ecology Websites

Summary: THE GLOBAL IMPACT OF SATELLITE-DERIVED POLAR WINDS ON MODEL FORECASTS by David A. Santek........................................................................................................... 1 2. Satellite-derived winds algorithm........................................................................... 6 2.1 Geostationary satellite winds algorithm

Wisconsin at Madison, University of

292

Satellite-based modeling of gross primary production in a seasonally moist tropical evergreen forest

  Environmental Sciences and Ecology Websites

Summary: -year satellite images from the VEGETATION (VGT) sensor onboard the SPOT-4 satellite (4/1998­12/2002) and the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Terra satellite (2000­2003). We reported

Saleska, Scott

293

Automatic radiometric normalization of multitemporal satellite imagery Morton J. Cantya,*, Allan A. Nielsenb

  Mathematics Websites

Summary: Automatic radiometric normalization of multitemporal satellite imagery Morton J. Cantya,*, Allan A; Radiometric normalization 1. Introduction Radiometric normalization of satellite imagery re- quires, among of image acquisition. For most historical satellite scenes, such data are not available and even


294

Automatic radiometric normalization of multitemporal satellite imagery with the iteratively re-weighted MAD transformation

  Mathematics Websites

Summary: Automatic radiometric normalization of multitemporal satellite imagery with the iteratively re with partly artificial data and then applied to multitemporal, multispectral satellite imagery. Substantial. Introduction Ground reflectance determination from satellite imagery requires, among other things


295

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING Int. J. Satell. Commun. Network. 2006; 24:261281

  Computer Technologies and Information Sciences Websites

Summary: INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING Int. J. Satell. Commun. Network: 10.1002/sat.841 Turbo-coded APSK modulations design for satellite broadband communications Riccardo phase shift keying (APSK) modulation with application to satellite broadband communications. APSK


296

Improved Explicit Congestion Notification for Satellite Networks Arjan Durresi*a

  Computer Technologies and Information Sciences Websites

Summary: of the greatest challenges before telecommunications industry in the 21st century. Satellite communicationImproved Explicit Congestion Notification for Satellite Networks Arjan Durresi*a , Mukundan University b Nayna Networks, Inc. ABSTRACT Due to the fundamental satellite system characteristics

Jain, Raj

297

Enhancing the Economics of Satellite Constellations via Staged Deployment and Orbital

  Engineering Websites

Summary: Enhancing the Economics of Satellite Constellations via Staged Deployment and Orbital Students #12;2 #12;Enhancing the Economics of Satellite Constellations via Staged Deployment and Orbital and Astronautics Abstract The "traditional" way of designing constellations of communications satellites


298

Relative equilibria of four identical satellites

  Mathematical Physics (arXiv)

Summary: We consider the Newtonian 5-body problem in the plane, where 4 bodies have the same mass m, which is small compared to the mass M of the remaining body. We consider the (normalized) relative equilibria in this system, and follow them to the limit when m/M -> 0. In some cases two small bodies will coalesce at the limit. We call the other equilibria the relative equilibria of four separate identical satellites. We prove rigorously that there are only three such equilibria, all already known after the numerical researches in [SaY]. Our main contribution is to prove that any equilibrium configuration possesses a symmetry, a statement indicated in [CLO2] as the missing key to proving that there is no other equilibrium.

Alain Albouy; Yanning Fu
2009-02-18

299

Constraining supersymmetry from the satellite experiments

  HEP - Phenomenology (arXiv)

Summary: In this paper we study the detectability of $\\gamma$-rays from dark matter annihilation in the subhalos of the Milky Way by the satellite-based experiments, EGRET and GLAST. We work in the frame of supersymmetric extension of the standard model and assume the lightest neutralino being the dark matter particles. Based on the N-body simulation of the evolution of dark matter subhalos we first calculate the average intensity distribution of this new class of $\\gamma$-ray sources by neutralino annihilation. It is possible to detect these $\\gamma$-ray sources by EGRET and GLAST. Conversely, if these sources are not detected the nature of the dark matter particls will be constrained by these experiments, which, however, depending on the uncertainties of the subhalo profile.

Xiao-Jun Bi
2007-12-10

300

Downburst Prediction Applications of Meteorological Geostationary Satellites

  CERN Preprints

Summary: A suite of products has been developed and evaluated to assess hazards presented by convective storm downbursts derived from the current generation of Geostationary Operational Environmental Satellite (GOES) (13-15). The existing suite of GOES downburst prediction products employs the GOES sounder to calculate risk based on conceptual models of favorable environmental profiles for convective downburst generation. A diagnostic nowcasting product, the Microburst Windspeed Potential Index (MWPI), is designed to infer attributes of a favorable downburst environment: 1) the presence of large convective available potential energy (CAPE), and 2) the presence of a surface-based or elevated mixed layer with a steep temperature lapse rate and vertical relative humidity gradient. These conditions foster intense convective downdrafts upon the interaction of sub-saturated air in the elevated or sub-cloud mixed layer with the storm precipitation core. This paper provides an updated assessment of the MWPI algorithm, present...

Pryor, Kenneth L
2014-01-01

301

The Extended Shapes of Galactic Satellites

  Astrophysics (arXiv)

Summary: We are exploring the extended stellar distributions of Galactic satellite galaxies and globular clusters. For seven objects studied thus far, the observed profile departs from a King function at large r, revealing a ``break population'' of stars. In our sample, the relative density of the ``break'' correlates to the inferred M/L of these objects. We discuss opposing hypotheses for this trend: (1) Higher M/L objects harbor more extended dark matter halos that support secondary, bound, stellar ``halos''. (2) The extended populations around dwarf spheroidals (and some clusters) consist of unbound, extratidal debris from their parent objects, which are undergoing various degrees of tidal disruption. In this scenario, higher M/L ratios reflect higher degrees of virial non-equilibrium in the parent objects, thus invalidating a precept underlying the use of core radial velocities to obtain masses.

S. R. Majewski; A. D. Forestell; J. C. Ostheimer; C. Palma; M. H. Siegel; S. Sohn; K. B. Westfall; R. J. Patterson; P. M. Frinchaboy; R. Link
2001-09-26

302

Symmetric Satellite Swarms and Choreographic Crystals

  CERN Preprints

Summary: In this paper, we introduce a natural dynamical analogue of crystalline order, which we call choreographic order. In an ordinary (static) crystal, a high degree of symmetry may be achieved through a careful arrangement of the fundamental repeated elements. In the dynamical analogue, a high degree of symmetry may be achieved by having the fundamental elements perform a carefully choreographed dance. For starters, we show how to construct and classify all symmetric satellite constellations. Then we explain how to generalize these ideas to construct and classify choreographic crystals more broadly. We introduce a quantity, called the "choreography" of a given configuration. We discuss the possibility that some (naturally occurring or artificial) many-body or condensed-matter systems may exhibit choreographic order, and suggest natural experimental signatures that could be used to identify and characterize such systems.

Boyle, Latham; Smith, Kendrick
2014-01-01

303

Submerged turbulence detection with optical satellites

  CERN Preprints

Summary: During fall periods in 2002, 2003 and 2004 three major oceanographic expeditions were carried out in Mamala Bay, Hawaii. These were part of the RASP Remote Anthropogenic Sensing Program. Ikonos and Quickbird optical satellite images of sea surface glint revealed ~100 m spectral anomalies in km^2 averaging patches in regions leading from the Honolulu Sand Island Municipal Outfall diffuser to distances up to 20 km. To determine the mechanisms behind this phenomenon, the RASP expeditions monitored the waters adjacent to the outfall with an array of hydrographic, optical and turbulence microstructure sensors in anomaly and ambient background regions. Drogue tracks and mean turbulence parameters for 2x10^4 microstructure patches were analyzed to understand complex turbulence, fossil turbulence and zombie turbulence near-vertical internal wave transport processes. The dominant mechanism appears to be generic to stratified natural fluids including planet and star atmospheres and is termed beamed zombie turbulence ma...

Gibson, Carl H; Bondur, Valery G; Leung, Pak T; Prandke, H; Vithanage, D
2007-01-01

304

Properties of cluster satellites in hydrodynamical simulations

  Astrophysics (arXiv)

Summary: We analyze the dynamical and thermal evolution of dark matter and ICM in hydrodynamical Tree-SPH simulations of galaxy clusters. Starting from a sample of 17 high-resolution objects, with virial mass ranging from 3 10^{14} to 1.7 10^{15} M_sun, we follow the build-up of the systems in dark matter and hot gas through the repeated merging of satellites along their merging history trees. We measure the self-bound mass fraction of subhaloes as a function of time after the merging, estimate the satellite mean orbital properties as a function of the mass ratio with the main cluster at merging time, and study the evolution of their internal velocity dispersion, gas temperature and entropy as the substructure is disrupted by various dynamical processes, reaching eventually thermo-dynamic equilibrium in the gravitational potential of the main cluster. We model some relevant properties of subhalo orbits, as the time of the first pericentric and apocentric passages, and the typical distances and velocities at the corresponding times. This survival study can be used to interpret the dynamics of observed merging clusters; as an example we apply our results to the system 1E0657-56. We show that, in the light of our results, the most likely interpretation of the data for this cluster points to the merger of a small group with mass M\\approx 1 10^{13} M_sun with a massive cluster with M\\approx 1.3 10^{15} M_sun.

Giuseppe Tormen; Lauro Moscardini; Naoki Yoshida
2004-03-04

305

Satellite Image Automatic MapperTM -SIAMTM -Patent pending - Andrea Baraldi University of Maryland Satellite Image Automatic MapperTM

  Geosciences Websites

Summary: Satellite Image Automatic MapperTM - SIAMTM - Patent pending - © Andrea Baraldi University MapperTM - SIAMTM - Patent pending - © Andrea Baraldi University of Maryland - Email: andrea.baraldi@hermes.geog.umd.edu #12;Satellite Image Automatic MapperTM - SIAMTM - Patent pending - © Andrea Baraldi University

Kuligowski, Bob

306

The use of Coral Physiology to combine Satellite SST and Insolation to trackSatellite SST and Insolation to track

  Geosciences Websites

Summary: ­ yes MORTALITY h t· MORTALITY ­ somewhat · Only tracks coral health during a bleaching event G l fThe use of Coral Physiology to combine Satellite SST and Insolation to trackSatellite SST and Insolation to track Daily Coral Health WilliamWilliam SkirvingSkirving, Susana, Susana EnríquezEnríquez, John

Kuligowski, Bob

307

TriAnd and its Siblings: Satellites of Satellites in the Milky Way Halo

  CERN Preprints

Summary: We explore the Triangulum-Andromeda (TriAnd) overdensity in the SPLASH (Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo) and SEGUE (the Sloan Extension for Galactic Understanding and Exploration) spectroscopic surveys. Milky Way main sequence turn-off stars in the SPLASH survey reveal that the TriAnd overdensity and the recently discovered PAndAS stream (Martin et al. 2014) share a common distance (D ~ 20 kpc), position on the sky, and line-of-sight velocity (V_GSR ~ 50 km/s). Similarly, A-type, giant, and main sequence turn-off stars selected from the SEGUE survey in the vicinity of the Segue 2 dwarf show that TriAnd is prevalent in these fields, with a velocity and distance similar to the Segue 2 satellite. The coincidence of the PAndAS stream and Segue 2 satellite in positional and velocity space to TriAnd suggests that these substructures are all associated, and may be a fossil record of group-infall onto the Milky Way halo. In this scenario, the Segue 2 satellite and PAndAS stream are...

Deason, A J; Hamren, K M; Koposov, S E; Gilbert, K M; Beaton, R L; Dorman, C E; Guhathakurta, P; Majewski, S R; Cunningham, E C
2014-01-01

308

High-latitude ionospheric convection models derived from Defense Meteorological Satellite Program ion drift

  Physics Websites

Summary: High-latitude ionospheric convection models derived from Defense Meteorological Satellite Program constructed using Defense Meteorological Satellite Program (DMSP) thermal ion drift measurements. The models

Michigan, University of

309

Satellite Application Facility for Numerical Weather Prediction Document NWPSAF-KN-UD-006

  Geosciences Websites

Summary: NWP SAF Satellite Application Facility for Numerical Weather Prediction Document NWPSAF-KN-UD-006 Satellite Application Facility on Numerical Weather Prediction (NWP SAF), under the Cooperation Agreement

Haak, Hein

310

FY 2008 AOP vs. Goals and Priorities Joint Center for Satellite Data Assimilation (JCSDA)

  Environmental Sciences and Ecology Websites

Summary: satellite data type, e.g. infrared sounding, microwave sounding, feature tracking winds, surface winds impact and observation minus background statistics for all major satellite sensors. 4. Preparation

Kuligowski, Bob

311

The Role of Mobile and Remote Sensing Satellites in Disaster Management

  CiteSeer

Summary: Abstract: Disaster management aim is human casualty decreasing in natural events such as earth quack, flood, thunderstorms and …. As well as in air crashes, accidents and…. In this paper we use mobile satellite services (MSS) and remote sensing satellites to provide this purpose. Mobile satellites contains 3 type of satellites; LEO, MEO and GEO. Remote sensing satellites are two categories: optical and microwave. In first section the introduction is presented, section two and three are about mobile satellites and remote sensing satellites, section four analyzes data and finally conclusion will be presented. Key words: disaster management, mobile satellite, remote sensing. I.

Mehdi Mari; Amir Kabir

312

Satellite Infall and the Growth of Bulges of Spiral Galaxies

  Astrophysics (arXiv)

Summary: For bulges of spiral galaxies, the concentration, or Sersic index, increases with bulge luminosity and bulge-to-disk ratio B/D (Andredakis, Peletier, & Balcells 1995, MNRAS, 275, 874). Does this trend trace the growth of bulges via satellite accretion? And, is satellite infall consistent with this trend? Aguerri, Balcells, & Peletier (2001, A&A, 367, 428) investigated this question with N-body simulations of the accretion of dense, spheroidal satellites. Here, we expand on that work by running N-body simulations of the accretion of satellites that have realistic densities. Satellites are modelled as disk-bulge structures with their own dark-matter halo. A realistic density scaling with the primary galaxy is ensured by using the Tully-Fisher relation. Our merger models show that most satellites disrupt before reaching the center. However, a bulge-disk decomposition of the surface density profile after the accretion shows an increase of both the B/D and the Sersic index n of the bulge. The increase in the mass and concentration of the inner Sersic component is due to inward piling up of disk material due to transient bars during the satellite orbital decay. This research is described in Eliche-Moral, Balcells, Aguerri, & Gonzalez-Garcia, 2005 (in preparation).

M. C. Eliche-Moral; M. Balcells; J. A. L. Aguerri; A. C. Gonzalez-Garcia
2005-01-18

313

Anisotropic Distribution of SDSS Satellite Galaxies: Planar (not Polar) Alignment

  Astrophysics (arXiv)

Summary: The distribution of satellite galaxies relative to isolated host galaxies in the Sloan Digital Sky Survey (SDSS) is investigated. Host-satellite systems are selected using three different methods, yielding samples of ~3300, ~1600, and \\~950 satellites. In the plane of the sky, the distributions of all three samples show highly significant deviations from circular symmetry (> 99.99%, > 99.99%, and 99.79% confidence levels, respectively), and the degree of anisotropy is a strong function of the projected radius, r_p, at which the satellites are found. For r_p < 100 kpc, the SDSS satellites are aligned preferentially with the major axes of the hosts. This is in stark contrast to the Holmberg effect, in which satellites are aligned with the minor axes of host galaxies. The degree of anisotropy in the distribution of the SDSS satellites decreases with r_p and is consistent with an isotropic distribution at of order the 1-sigma level for 250 kpc < r_p < 500 kpc.

Tereasa G. Brainerd
2005-06-15

314

The Distribution of Satellite Galaxies: The Great Pancake

  Astrophysics (arXiv)

Summary: The 11 known satellite galaxies within 250 kpc of the Milky Way lie close to a great circle on the sky. We use high resolution N-body simulations of galactic dark matter halos to test if this remarkable property can be understood within the context of the cold dark matter cosmology. We construct halo merger trees from the simulations and use a semianalytic model to follow the formation of satellite galaxies. We find that in all 6 of our simulations, the 11 brightest satellites are indeed distributed along thin, disk-like structures analogous to that traced by the Milky Way's satellites. This is in sharp contrast to the overall distributions of dark matter in the halo and of subhalos within it which, although triaxial, are not highly aspherical. We find that the spatial distribution of satellites is significantly different from that of the most massive subhalos but is similar to that of the subset of subhalos that had the most massive progenitors at earlier times. The elongated disk-like structure delineated by the satellites has its long axis aligned with the major axis of the dark matter halo. We interpret our results as reflecting the preferential infall of satellites along the spines of a few filaments of the cosmic web.

Noam I Libeskind; Carlos S Frenk; Shaun Cole; John C Helly; Adrian Jenkins; Julio F Navarro; Chris Power
2005-03-18

315

LARES succesfully launched in orbit: satellite and mission description

  General Relativity & Quantum Cosmology (arXiv)

Summary: On February 13th 2012, the LARES satellite of the Italian Space Agency (ASI) was launched into orbit with the qualification flight of the new VEGA launcher of the European Space Agency (ESA). The payload was released very accurately in the nominal orbit. The name LARES means LAser RElativity Satellite and summarises the objective of the mission and some characteristics of the satellite. It is, in fact, a mission designed to test Einstein's General Relativity Theory (specifically 'frame dragging' and Lense-Thirring effect). The satellite is passive and covered with optical retroreflectors that send back laser pulses to the emitting ground station. This allows accurate positioning of the satellite, which is important for measuring the very small deviations from Galilei-Newton's laws. In 2008, ASI selected the prime industrial contractor for the LARES system with a heavy involvement of the universities in all phases of the programme, from the design to the construction and testing of the satellite and separation system. The data exploitation phase started immediately after the launch under a new contract between ASI and those universities. Tracking of the satellite is provided by the International Laser Ranging Service. Due to its particular design, LARES is the orbiting object with the highest known mean density in the solar system. In this paper, it is shown that this peculiarity makes it the best proof particle ever manufactured. Design aspects, mission objectives and preliminary data analysis will be also presented.

Antonio Paolozzi; Ignazio Ciufolini
2013-05-29

316

Comparing galactic satellite properties in hydrodynamical and Nbody simulations

  CERN Preprints

Summary: In this work, we examine the different properties of galactic satellites in hydrodynamical and pure dark matter simulations. We use three pairs of simulations (collisional and collision-less) starting from identical initial conditions. We concentrate our analysis on pairs of satellites in the hydro and Nbody runs that form from the same Lagrangian region. We look at the radial positions, mass loss as a function of time and orbital parameters of these "twin" satellites. We confirm an overall higher radial density of satellites in the hydrodynamical runs, but find that trends in the mass loss and radial position of these satellites in the inner and outer region of the parent halo differ from the pure dark matter case. In the outskirts of the halo (~70% of the virial radius) satellites experience a stronger mass loss and higher dynamical friction in pure dark matter runs. The situation is reversed in the central region of the halo, where hydrodynamical satellites have smaller apocenter distances and suffer highe...

Schewtschenko, Jascha A
2010-01-01

317

The stellar-subhalo mass relation of satellite galaxies

  CERN Preprints

Summary: We extend the abundance matching technique (AMT) to infer the satellite-subhalo and central-halo mass relations (MRs) of galaxies, as well as the corresponding satellite conditional mass functions (CMFs). We use the observed galaxy stellar mass function (GSMF) decomposed into centrals and satellites and the LCDM halo/subhalo mass functions as inputs. We explore the effects of defining the subhalo mass at the time of accretion (m_acc) vs. at the time of observation (m_obs). We test the standard assumption that centrals and satellites follow the same MRs, showing that this assumption leads to predictions in disagreement with observations, specially for m_obs. Instead, when the satellite-subhalo MRs are constrained following our AMT, they are always different from the central-halo MR: the smaller the stellar mass (Ms), the less massive is the subhalo of satellites as compared to the halo of centrals of the same Ms. On average, for Ms<2x10^11Msol, the dark mass of satellites decreased by 60-65% with respect to...

Rodriguez-Puebla, A; Avila-Reese, V
2012-01-01

318

Lasers for coherent optical satellite links with large dynamics

  CERN Preprints

Summary: We present the experimental realization of a laser system for ground to satellite optical Doppler ranging at the atmospheric turbulence limit. Such a system needs to display good frequency stability (a few parts in 10^{-14}) whilst allowing large and well controlled frequency sweeps of +/- 12 GHz at rates exceeding 100 MHz/s. Furthermore it needs to be sufficiently compact and robust for transportation to different astronomical observation sites where it is to be interfaced with satellite ranging telescopes. We demonstrate that our system fulfills those requirements and should therefore allow operation of ground to low Earth orbit satellite coherent optical links limited only by atmospheric turbulence.

Chiodo, Nicola; Acef, Ouali; Clairon, Andre; Wolf, Peter
2013-01-01

319

Satellite probing General Relativity and its extensions and Kolmogorov analysis

  General Relativity & Quantum Cosmology (arXiv)

Summary: We apply the Kolmogorov statistic to analyse the residual data of two LAGEOS satellites on General Relativistic Lense-Thirring effect, and show that it reveals a tiny difference in the properties of the satellites, possibly related to Yarkovsky-Rubincam effect. The recently launched LAser RElativity Satellite (LARES) can provide constraints to the extensions of General Relativity such as the Chern-Simons (CS) gravity with metric coupled to a scalar field through the Pontryagin density, so an explicit dependence on the frame dragging measurements vs the CS parameter is given.

V. G. Gurzadyan; I. Ciufolini; S. Sargsyan; G. Yegorian; S. Mirzoyan; A. Paolozzi
2013-06-24

320

Integrated Connection Admission Control and Bandwidth on Demand Algorithm for a Broadband Satellite Network with Heterogeneous Traffic

  Engineering Websites

Summary: and signal processing on-board the satellite(s). One solution is based on a geo-synchronous (GEO) satellite in the system falls well within ITU's Quality of Service (QoS) specification for GEO-based satellite systems applications using low earth orbit (LEO) satellites, medium earth orbit (MEO) satellites, and geo

Rosenberg, Catherine P.

321

Dark matter subhalos and dwarf satellites

  CERN Preprints

Summary: The Via Lactea simulation of the dark matter halo of the Milky Way predicts the existence of many thousands of bound subhalos distributed approximately with equal mass per decade of mass. Here we show that: a) a similar steeply rising subhalo mass function is also present at redshift 0.5 in an elliptical-sized halo simulated with comparable resolution in a different cosmology. Compared to Via Lactea, this run produces nearly a factor of two more subhalos with large circular velocities; b) the fraction of Via Lactea mass brought in by subhalos that have a surviving bound remnant today with present-day peak circular velocity Vmax>2 km/s (>10 km/s) is 45% (30%); c) because of tidal mass loss, the number of subhalos surviving today that reached a peak circular velocity of >10 km/s throughout their lifetime exceeds half a thousand, five times larger than their present-day abundance and more than twenty times larger than the number of known satellites of the Milky Way; e) unless the circular velocity profiles of Ga...

Madau, Piero; Kuhlen, Michael
2008-01-01

322

The population of natural Earth satellites

  CERN Preprints

Summary: We have for the first time calculated the population characteristics of the Earth's irregular natural satellites (NES) that are temporarily captured from the near-Earth-object (NEO) population. The steady-state NES size-frequency and residence-time distributions were determined under the dynamical influence of all the massive bodies in the solar system (but mainly the Sun, Earth, and Moon) for NEOs of negligible mass. To this end, we compute the NES capture probability from the NEO population as a function of the latter's heliocentric orbital elements and combine those results with the current best estimates for the NEO size-frequency and orbital distribution. At any given time there should be at least one NES of 1-meter diameter orbiting the Earth. The average temporarily-captured orbiter (TCO; an object that makes at least one revolution around the Earth in a co-rotating coordinate system) completes $(2.88\\pm0.82)\\rev$ around the Earth during a capture event that lasts $(286\\pm18)\\days$. We find a small pre...

Granvik, Mikael; Jedicke, Robert
2011-01-01

323

Astrometric Microlensing with the GAIA satellite

  Astrophysics (arXiv)

Summary: GAIA is the ``super-Hipparcos'' survey satellite selected as a Cornerstone 6 mission by the European Space Agency. GAIA can measure microlensing by the small excursions of the light centroid that occur during events. The all-sky source-averaged astrometric microlensing optical depth is about 10^{-5}. Some 25000 sources will have a significant variation of the centroid shift, together with a closest approach, during the lifetime of the mission. A covariance analysis is used to study the propagation of errors and the estimation of parameters from realistic sampling of the GAIA datastream of transits in the along-scan direction during microlensing events. Monte Carlo simulations are used to study the 2500 events for which the mass can be recovered with an error of less than 50 per cent. These high quality events are dominated by disk lenses within a few tens of parsecs and source stars within a few hundred parsecs. We show that the local mass function can be recovered from the high quality sample to good accuracy. GAIA is the first instrument with the capabilities of measuring the mass locally in very faint objects like black holes and very cool white and brown dwarfs. For only 5 per cent of all astrometric events will GAIA record even one photometric datapoint. There is a need for a dedicated telescope that densely samples the Galactic Centre and spiral arms, as this can improve the accuracy of parameter estimation by a factor of about 10.

V. A. Belokurov; N. W. Evans
2001-12-11

324

Dwarf Galaxy Clustering and Missing Satellites

  CERN Preprints

Summary: At redshifts around 0.1 the CFHT Legacy Survey Deep fields contain some 6x10^4 galaxies spanning the mass range from 10^5 to 10^12 Msun. We measure the stellar mass dependence of the two point correlation using angular measurements to largely bypass the errors, approximately 0.02 in the median, of the photometric redshifts. Inverting the power-law fits with Limber's equation we find that the auto-correlation length increases from a very low 0.4hMpc at 10^5.5 Msun to the conventional 4.5hMpc at 10^10.5 Msun. The power law fit to the correlation function has a slope which increases from gamma approximately 1.6 at high mass to gamma approximately 2.3 at low mass. The spatial cross-correlation of dwarf galaxies with more massive galaxies shows fairly similar trends, with a steeper radial dependence at low mass than predicted in numerical simulations of sub-halos within galaxy halos. To examine the issue of missing satellites we combine the cross-correlation measurements with our estimates of the low mass galaxy n...

Carlberg, R G; Le Borgne, D
2008-01-01

325

Tidal gravitational effects in a satellite

  General Relativity & Quantum Cosmology (arXiv)

Summary: Atomic wave interferometers are tied to a telescope pointing towards a faraway star in a nearly free falling satellite. Such a device is sensitive to the acceleration and the rotation relatively to the local inertial frame and to the tidal gravitational effects too. We calculate the rotation of the telescope due to the aberration and the deflection of the light in the gravitational field of a central mass (the Earth and Jupiter). Within the framework of a general parametrized description of the problem, we discuss the contributions which must be taken into account in order to observe the Lense-Thirring effect. Using a geometrical model, we consider some perturbations to the idealized device and we calculate the corresponding effect on the periodic components of the signal. Some improvements in the knowledge of the gravitational field are still necessary as well as an increase of the experimental capabilities; however our conclusions support a reasonable optimism for the future. Finally we put forward the necessity of a more complete, realistic and powerful model in order to obtain a definitive conclusion on the feasibility of the experiment as far as the observation of the Lense-Thirring effect is involved.

Philippe Tourrenc; Marie-Christine Angonin-Willaime; Xavier Ovido
2004-07-23

326

Generalized Morse Potential: Symmetry and Satellite Potentials

  HEP - Theory (arXiv)

Summary: We study in detail the bound state spectrum of the generalized Morse potential~(GMP), which was proposed by Deng and Fan as a potential function for diatomic molecules. By connecting the corresponding Schr\\"odinger equation with the Laplace equation on the hyperboloid and the Schr\\"odinger equation for the P\\"oschl-Teller potential, we explain the exact solvability of the problem by an $so(2,2)$ symmetry algebra, and obtain an explicit realization of the latter as $su(1,1) \\oplus su(1,1)$. We prove that some of the $so(2,2)$ generators connect among themselves wave functions belonging to different GMP's (called satellite potentials). The conserved quantity is some combination of the potential parameters instead of the level energy, as for potential algebras. Hence, $so(2,2)$ belongs to a new class of symmetry algebras. We also stress the usefulness of our algebraic results for simplifying the calculation of Frank-Condon factors for electromagnetic transitions between rovibrational levels based on different electronic states.

A. Del Sol Mesa; C. Quesne; Yu. F. Smirnov
1997-08-06

327

Submerged turbulence detection with optical satellites

  Astrophysics (arXiv)

Summary: During fall periods in 2002, 2003 and 2004 three major oceanographic expeditions were carried out in Mamala Bay, Hawaii. These were part of the RASP Remote Anthropogenic Sensing Program. Ikonos and Quickbird optical satellite images of sea surface glint revealed ~100 m spectral anomalies in km^2 averaging patches in regions leading from the Honolulu Sand Island Municipal Outfall diffuser to distances up to 20 km. To determine the mechanisms behind this phenomenon, the RASP expeditions monitored the waters adjacent to the outfall with an array of hydrographic, optical and turbulence microstructure sensors in anomaly and ambient background regions. Drogue tracks and mean turbulence parameters for 2x10^4 microstructure patches were analyzed to understand complex turbulence, fossil turbulence and zombie turbulence near-vertical internal wave transport processes. The dominant mechanism appears to be generic to stratified natural fluids including planet and star atmospheres and is termed beamed zombie turbulence maser action (BZTMA). Most of the bottom turbulent kinetic energy is converted to ~100 m fossil turbulence waves. These activate secondary (zombie) turbulence in outfall fossil turbulence patches that transmit heat, mass, chemical species, momentum and information vertically to the sea surface for detection in an efficient maser action. The transport is beamed in intermittent mixing chimneys.

Carl H. Gibson; R. Norris Keeler; Valery G. Bondur; Pak T. Leung; H. Prandke; D. Vithanage
2007-09-05

328

RESEARCH Open Access Application of satellite precipitation data to

  Geosciences Websites

Summary: RESEARCH Open Access Application of satellite precipitation data to analyse and model arbovirus GEOGRAPHICS © 2011 Schuster et al; licensee BioMed Central Ltd. This is an Open Access article distributed

Ebert, Beth

329

Risk management of student-run small satellite programs

  MIT - DSpace

Summary: This paper proposes an approach for failure mode identification in university-affiliated, small satellite programs. These small programs have a unique set of risks due to many factors, including a typically inexperienced ...

Deems, Elizabeth (Elizabeth Carolina)
2007-01-01

330

Digital Video Broadcasting By Satellite Matthew C. Valenti

  Computer Technologies and Information Sciences Websites

Summary: Network Systems. DirecTV. M.C. Valenti ( Lane Department of Computer Science and Electrical Engineering Providers Digital Satellite Television in the United States DirecTV Spinoff of Hughes Network Systems. Began

Valenti, Matthew C.

331

Title: Worldview 2 Satellite Image of York University Data Creator /

  Computer Technologies and Information Sciences Websites

Summary: ;Keywords (Place): Toronto, Ontario; North York, Ontario; York University, Ontario Keywords (Subject@yorku.ca) Citation: "Worldview 2 Satellite Image of York University, North York, Ontario, July 25, 2012". Longmont


332

Magnetic attitude control for satellites Jan Tommy Gravdahl,

  Engineering Websites

Summary: c surveillance from a LEO satellite using the maritime Automatic Identi cation System (AIS) recently introduced Fig. 1. Prototype of nCube illustrating the size and solar panels. by the International Maritime

Gravdahl, Jan Tommy

333

Micro-electromagnetic formation flight of satellite systems

  MIT - DSpace

Summary: Electromagnetic formation flight (EMFF) investigates the concept of using electromagnets to provide the forces to maintain a satellite's relative position in a formation. Thus far, high temperature superconducting (HTS) ...

Sakaguchi, Aya, S.M. Massachusetts Institute of Technology
2007-01-01

334

Satellite constellation design for mid-course ballistic missile intercept

  MIT - DSpace

Summary: This thesis will establish a conceptual approach to the design of constellations for satellite-based mid-course missile defense. The ballistic missile intercept problem leads to a new paradigm of coverage where interceptor ...

Sauter, Luke Michael, 1979-
2004-01-01

335

An integrated evolutionary model approach to small satellite engineering

  MIT - DSpace

Summary: A deficiency exists in the use of detailed integrated modeling in the design, fabrication, and operations of small satellites (<180kg). This need led to the design of the Integrated Evolutionary Model (IEM) approach to ...

Robinson, Joseph B. (Joseph Brian)
2010-01-01

336

Atmospheric Density Reconstruction Using Satellite Orbit Tomography1

  Engineering Websites

Summary: neutral density models are required for the reduction of orbit prediction errors for satellites = generalized distance y = measurement vector, km2 /s2 y = net derived measurement, km2 /s2 = drag ballistic

Wohlberg, Brendt

337

Satellite and Radar Meteorology Dr. Oleksandr Karabanov (Aleks)

  Geosciences Websites

Summary: recess - Thursday, October 18, 2012 17 Satellite Orbits and Navigation Tuesday, October 23, 2012 18 Black, representing GT, etc) - car accident - death in family Examples of un-excused absence: - overslept - boyfriend

Black, Robert X.

338

The Elemental Abundance Distributions of Milky Way Satellite Galaxies

  CERN Preprints

Summary: The chemical compositions of the stars in Milky Way (MW) satellite galaxies reveals the history of gas flows and star formation (SF) intensity. This talk presented a Keck/DEIMOS spectroscopic survey of the Fe, Mg, Si, Ca, and Ti abundances of nearly 3000 red giants in eight MW dwarf satellites. The metallicity and alpha-to-iron ratio distributions obey the following trends: (1) The more luminous galaxies are more metal-rich, indicating that they retained gas more efficiently than the less luminous galaxies. (2) The shapes of the metallicity distributions of the more luminous galaxies require gas infall during their SF lifetimes. (3) At [Fe/H] < -1.5, [alpha/Fe] falls monotonically with increasing [Fe/H] in all MW satellites. One interpretation of these trends is that the SF timescale in any MW satellite is long enough that Type Ia supernovae exploded for nearly the entire SF lifetime.

Kirby, Evan N
2010-01-01

339

Why Baryons Matter: The Kinematics of Dwarf Spheroidal Satellites

  CERN Preprints

Summary: We use some of the highest resolution cosmological simulations ever produced of Milky Way-mass galaxies that include both baryons and dark matter to show that baryonic physics (energetic feedback from supernovae and subsequent tidal stripping) significantly reduces the dark matter mass in the central regions of luminous satellite galaxies. The reduced central masses of the simulated satellites reproduce the observed internal dynamics of Milky Way and M31 satellites as a function of luminosity. Including baryonic physics in Cold Dark Matter models naturally explains the observed low dark matter densities in the Milky Way's dwarf spheroidal population. Our simulations therefore resolve the tension between kinematics predicted in Cold Dark Mater theory and observations of satellites, without invoking alternative forms of dark matter.

Brooks, Alyson M
2012-01-01

340

Search for Dark Matter Satellites using the FERMI-LAT

  HEP - Experiment (arXiv)

Summary: Numerical simulations based on the Lambda-CDM model of cosmology predict a large number of as yet unobserved Galactic dark matter satellites. We report the results of a Large Area Telescope (LAT) search for these satellites via the gamma-ray emission expected from the annihilation of weakly interacting massive particle (WIMP) dark matter. Some dark matter satellites are expected to have hard gamma-ray spectra, finite angular extents, and a lack of counterparts at other wavelengths. We sought to identify LAT sources with these characteristics, focusing on gamma-ray spectra consistent with WIMP annihilation through the $b \\bar b$ channel. We found no viable dark matter satellite candidates using one year of data, and we present a framework for interpreting this result in the context of numerical simulations to constrain the velocity-averaged annihilation cross section for a conventional 100 GeV WIMP annihilating through the $b \\bar b$ channel.

The Fermi LAT Collaboration; M. Ackermann; A. Albert; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; K. Bechtol; R. Bellazzini; R. D. Blandford; E. D. Bloom; E. Bonamente; A. W. Borgland; E. Bottacini; T. J. Brandt; J. Bregeon; M. Brigida; P. Bruel; R. Buehler; T. H. Burnett; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; J. M. Casandjian; C. Cecchi; E. Charles; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; J. Conrad; S. Cutini; F. de Palma; C. D. Dermer; S. W. Digel; E. do Couto e Silva; P. S. Drell; A. Drlica-Wagner; R. Essig; L. Falletti; C. Favuzzi; S. J. Fegan; W. B. Focke; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; S. Germani; N. Giglietto; F. Giordano; M. Giroletti; T. Glanzman; G. Godfrey; I. A. Grenier; S. Guiriec; M. Gustafsson; D. Hadasch; M. Hayashida; X. Hou; R. E. Hughes; R. P. Johnson; A. S. Johnson; T. Kamae; H. Katagiri; J. Kataoka; J. Knodlseder; M. Kuss; J. Lande; L. Latronico; S. -H. Lee; A. M. Lionetto; M. Llena Garde; F. Longo; F. Loparco; M. N. Lovellette; P. Lubrano; M. N. Mazziotta; J. E. McEnery; P. F. Michelson; W. Mitthumsiri; T. Mizuno; A. A. Moiseev; C. Monte; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; M. Naumann-Godo; J. P. Norris; E. Nuss; T. Ohsugi; A. Okumura; E. Orlando; J. F. Ormes; M. Ozaki; D. Paneque; V. Pelassa; M. Pierbattista; F. Piron; G. Pivato; T. A. Porter; S. Raino; R. Rando; M. Razzano; A. Reimer; O. Reimer; S. Ritz; H. F. -W. Sadrozinski; N. Sehgal; C. Sgro; E. J. Siskind; P. Spinelli; L. Strigari; D. J. Suson; H. Tajima; H. Takahashi; T. Tanaka; J. G. Thayer; J. B. Thayer; L. Tibaldo; M. Tinivella; D. F. Torres; E. Troja; Y. Uchiyama; T. L. Usher; J. Vandenbroucke; V. Vasileiou; G. Vianello; V. Vitale; A. P. Waite; P. Wang; B. L. Winer; K. S. Wood; Z. Yang; S. Zalewski; S. Zimmer
2012-01-12

341

Satellite Measurements Reveal Persistent Small-Scale Features in

  Geosciences Websites

Summary: forcing is governed by the conservation of angular momentum, which implies that ocean circulation- surements of sea surface roughness obtained at multiple azimuths as the satellite moves along its orbit. Sca

Kurapov, Alexander

342

The Fundamental Line of the Local Group Satellites

  Astrophysics (arXiv)

Summary: We present a new correlation between the mass-to-light (M/L) ratio and the mean metallicity for the satellites of the Local Group. This relation together with their central surface brightness define a Fundamental Line where metal poor and low surface brightness dwarfs are dark matter dominated while metal rich high surface brightness systems will have a low M/L ratio. This Fundamental Line is independent of distance to the central galaxy (M31 and the Milky Way) and morphological type among other global parameters as their star formation history. The new M/L-metallicity relation indicates that dwarf spheroidal galaxies are dark matter confined. It can be interpreted if satellites experienced a continuous loss of metals with a final episode of gas ejection at the end of the star formation epoch. Only Globular Clusters are found to lie outside the Fundamental Line of dwarf satellites. Unlike satellite galaxies they are not dark matter confined.

Francisco Prada; Andreas Burkert
2001-08-17

343

Dynamic resource allocation DAMA alternatives study for satellite communications systems

  MIT - DSpace

Summary: We consider the design of demand assigned multiple access (DAMA) algorithms that efficiently utilize limited RF uplink resources for packet switched military satellite communication networks. In previous work, we designed ...

Yao, Huan

344

Formation of dSph Satellites without Dark Matter

  CERN Preprints

Summary: Recently it was shown that low-mass galaxies containing no dark matter can naturally evolve to dSph-like satellites in a tidal field. Such dSph-like satellites fake total domination by dark matter. If this is correct then it must be possible to assemble appropriate precursors of dSph satellites. The genesis of dwarf galaxies in tidal tails appears to be a likely possibility. This is documented by theoretical work and observational surveys. However, it is not yet clear if the Milky Way could have sustained one or two mergers or fly-bys that were mild enough not to have destroyed the Galactic disc. The tidal arms could have been pulled from the incoming galaxy. Also, this scenario has to account for the correlation between brightness and metal abundance displayed by the Galactic dSph satellites, and lead to at least some debris on bound eccentric orbits.

Kroupa, P
1998-01-01

345

Upper-bounding bias errors in satellite navigation

  CERN Preprints

Summary: A satellite navigation system for a safety critical application is required to provide an integrity alert of any malfunction; the probability that a navigation positioning error exceeds a given alert limit without an integrity alert is required to be smaller than a given integrity risk. So far, a little number of applications provide integrity alerts, because signal propagation from a satellite to a receiver depends on diversified phenomena and makes probabilistic upper-bound of possible threats difficult. To widen application fields of satellite navigation, two methods to upper-bound wide classes of bias errors are shown in this paper. The worst bias error in a maximum likelihood estimate caused by an interference signal within a given small power is derived. A novel inequality condition with a clock bias error and magnification coefficients that upper-bounds a horizontal position error is presented. Robustness of the inequality condition is numerically shown based on actual configurations of satellites.

Iwamoto, Takashi
2014-01-01

346

Search for Dark Matter Satellites using the FERMI-LAT

  CERN Preprints

Summary: Numerical simulations based on the Lambda-CDM model of cosmology predict a large number of as yet unobserved Galactic dark matter satellites. We report the results of a Large Area Telescope (LAT) search for these satellites via the gamma-ray emission expected from the annihilation of weakly interacting massive particle (WIMP) dark matter. Some dark matter satellites are expected to have hard gamma-ray spectra, finite angular extents, and a lack of counterparts at other wavelengths. We sought to identify LAT sources with these characteristics, focusing on gamma-ray spectra consistent with WIMP annihilation through the $b \\bar b$ channel. We found no viable dark matter satellite candidates using one year of data, and we present a framework for interpreting this result in the context of numerical simulations to constrain the velocity-averaged annihilation cross section for a conventional 100 GeV WIMP annihilating through the $b \\bar b$ channel.

Ackermann, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bottacini, E; Brandt, T J; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Burnett, T H; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Charles, E; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Cutini, S; de Palma, F; Dermer, C D; Digel, S W; Silva, E do Couto e; Drell, P S; Drlica-Wagner, A; Essig, R; Falletti, L; Favuzzi, C; Fegan, S J; Focke, W B; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Germani, S; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Guiriec, S; Gustafsson, M; Hadasch, D; Hayashida, M; Hou, X; Hughes, R E; Johnson, R P; Johnson, A S; Kamae, T; Katagiri, H; Kataoka, J; Knodlseder, J; Kuss, M; Lande, J; Latronico, L; Lee, S -H; Lionetto, A M; Garde, M Llena; Longo, F; Loparco, F; Lovellette, M N; Lubrano, P; Mazziotta, M N; McEnery, J E; Michelson, P F; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Naumann-Godo, M; Norris, J P; Nuss, E; Ohsugi, T; Okumura, A; Orlando, E; Ormes, J F; Ozaki, M; Paneque, D; Pelassa, V; Pierbattista, M; Piron, F; Pivato, G; Porter, T A; Raino, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Ritz, S; Sadrozinski, H F -W; Sehgal, N; Sgro, C; Siskind, E J; Spinelli, P; Strigari, L; Suson, D J; Tajima, H; Takahashi, H; Tanaka, T; Thayer, J G; Thayer, J B; Tibaldo, L; Tinivella, M; Torres, D F; Troja, E; Uchiyama, Y; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, A P; Wang, P; Winer, B L; Wood, K S; Yang, Z; Zalewski, S; Zimmer, S
2012-01-01

347

MODIS AND OMI SATELLITE OBSERVATIONS SUPPORTING AIR QUALITY MONITORING

  Geosciences Websites

Summary: improvements in temporal and spatial resol- utions and enhancements in radiometric accuracy, thus encouraging, the synoptic view and the daily repetition cycle of satellite-based measurements strengthen the potential

Curci, Gabriele

348

A Constrained Attitude Control Module for Small Satellites

  Engineering Websites

Summary: The University of Texas at Austin Small Satellite Conference Logan, Utah August 14, 2012 #12;Motivation Common&C Module being assembled Right: Front and back of the flight cold- gas thruster module #12;6 Traditional

Lightsey, Glenn

349

Spectrum planning and performance evaluation between heterogeneous satellite networks

  Engineering Websites

Summary: Radiocommunications Laboratory, School of Electrical and Computer Engineering, National Technical University of Athens,5]. One of the potential problems is coexistence with the co-primary fixed satellite service. Up today

Vouyioukas, Demosthenes

350

Studies on Replication of Cucumber Mosaic Virus Satellite RNA

  University of California eScholarship Repository

Summary: plant genome since there is a noticeable segmental sequenceplant genome. In addition, the satellite RNA of peanut stunt virus ( PSV) nucleotide sequenceplants. Although satRNA has no sequence homology with CMV genome,

Choi, Soon Ho
2011-01-01

351

Rception des signaux AIS par satellite Raoul PRVOST

  Engineering Websites

Summary: organisé en cellules 29/09/2011 4/46 #12;Automatic Identification System · Bateaux à portée l'un de l;Réception par satellite · Collisions entre les messages des différentes cellules · Utilisation de méthodes

Dobigeon, Nicolas

352

Sea Oil Field Satellite Monitoring: An Opera3onal View

  Geosciences Websites

Summary: Sea Oil Field Satellite Monitoring: An Opera3onal View Maurizio, Camp Springs, MD 20746 #12;Outline Introduc:on Sea oil fields Synthe:c Aperture Radar SAR sea oil field monitoring Conclusions 2 M Migliaccio #12;Introduc

Kuligowski, Bob

353

Achieving bounded delay on a time-varying satellite uplink

  MIT - DSpace

Summary: In this paper, we investigate the packet transmission delay in a time varying satellite uplink. Specifically, we are interested in bounding the packet transmission delay within the terminal router for uplink traffic in a ...

Wysocarski, Jeffrey S.

354

EUMETSAT Meteorological Satellite conference, Cordoba, 21/9/2010 observation

  Geosciences Websites

Summary: discrimination · Combined receiver including: ­ Multi channel Mie receiver ­ Dual channel Rayleigh receiver scenario can be changed 8 times per orbit possibility of targeting #12;10EUMETSAT Meteorological Satellite

Stoffelen, Ad

355

Formation of dSph Satellites without Dark Matter

  Astrophysics (arXiv)

Summary: Recently it was shown that low-mass galaxies containing no dark matter can naturally evolve to dSph-like satellites in a tidal field. Such dSph-like satellites fake total domination by dark matter. If this is correct then it must be possible to assemble appropriate precursors of dSph satellites. The genesis of dwarf galaxies in tidal tails appears to be a likely possibility. This is documented by theoretical work and observational surveys. However, it is not yet clear if the Milky Way could have sustained one or two mergers or fly-bys that were mild enough not to have destroyed the Galactic disc. The tidal arms could have been pulled from the incoming galaxy. Also, this scenario has to account for the correlation between brightness and metal abundance displayed by the Galactic dSph satellites, and lead to at least some debris on bound eccentric orbits.

Pavel Kroupa
1998-01-07

356

Multi-stakeholder Interactive Simulation for Federated Satellite Systems

  MIT - DSpace

Summary: Federated satellite systems (FSS) are a new class of space-based systems which emphasize a distributed architecture. New information exchanging functions among FSS members enable data transportation, storage, and processing ...

Grogan, Paul Thomas

357

Developing Mode-Rich Satellite Software by Refinement Alexei Iliasova

  Engineering Websites

Summary: development. The proposed approach is validated by a formal development of the Attitude and Orbit Control described in this paper generalises the results of the development of satellite Attitude and Orbit Control

Southampton, University of

358

International Global Navigation Satellite Systems Society IGNSS Symposium 2007

  Engineering Websites

Summary: second time-to-alarm requirement. Further, at the time the MOPS were initiated, selective availability was active, necessitating frequent clock updates for each satellite. Therefore, at that time it was decided

Stanford University

359

Dwarf-spheroidal satellites: are they of tidal origin?

  Astrophysics (arXiv)

Summary: The Milky Way and Andromeda must have formed through an initial epoch of sub-structure merging. As a result of fundamental physical conservation laws tidal-dwarf galaxies (TDGs) have likely been produced. Here we show that such TDGs appear, after a Hubble-time of dynamical evolution in the host dark-matter halo, as objects that resemble known dSph satellite galaxies. We discuss the possibility that some of the Milky Way's satellites may be of tidal origin.

M. Metz; P. Kroupa
2007-01-10

360

The Effect of Satellite Galaxies on Gravitational Lensing Flux Ratios

  Astrophysics (arXiv)

Summary: Gravitational lenses with anomalous flux ratios are often cited as possible evidence for dark matter satellites predicted by simulations of hierarchical merging in cold dark matter cosmogonies. We show that the fraction of quads with anomalous flux ratios depends primarily on the total mass and spatial extent of the satellites, and the characteristic lengthscale R of their distribution. If R is 100 kpc, then for a moderately elliptical galaxy with a line-of-sight velocity dispersion of 250 km/s, a mass of 3 x 10^9 solar masses in highly-concentrated (Plummer model) satellites is needed for 20% of quadruplets to show anomalous flux ratios, rising to 1.25 x 10^10 solar masses for 50%. Several times these masses are required if the satellites have more extended Hernquist profiles. Compared to a typical elliptical, the flux ratios of quads formed by typical edge-on disc galaxies with maximum discs are significantly less susceptible to changes through substructure -- three times the mass in satellite galaxies is needed to affect 50% of the systems. In many of the lens systems with anomalous flux ratios, there is evidence for visible satellites (e.g., B2045+265 or MG0414+0534). We show that optically identified substructure should not be preponderant among lens systems with anomalies. There are two possible resolutions of this difficulty. First, in some cases, visible substructure may be projected within or close to the Einstein radius and wrongly ascribed as the culprit, whereas dark matter substructure is causing the flux anomaly. Second, bright satellites, in which baryon cooling and condensation has taken place, may have higher central densities than dark satellites, rendering them more efficient at causing flux anomalies.

E. M. Shin; N. W. Evans
2008-01-16

361

Testing modified gravity with motion of satellites around galaxies

  CERN Preprints

Summary: A modified gravity (MOG) theory that has been successfully fitted to galaxy rotational velocity data, cluster data and the Bullet Cluster 1E0657-56 is fitted to the motion of satellite galaxies around host galaxies at distances 50-400 kpc providing a new sensitive test to the MOG. We show that observational data from the Sloan Digital Sky Survey strongly favor the MOG, while Milgrom's MOND fails on these scales by predicting nearly constant rms velocities of satellites.

Moffat, J W
2007-01-01

362

Pre-solution of the perturbed motion of artificial satellite

  CERN Preprints

Summary: The authors try to find a good solution of an artificial satellite motion under the influence of J2 gravity in terms of KS variables by using Picard Iterative Method. The result shows that there are many solutions for this problem depends on the initial guess solutions, so the choice of correct and convince initial guess is very difficult. Applications of the method applied on many satellites.

Hassan, Inalds A; Basha, Mohammad A F
2012-01-01

363

Satellite Accretion Onto Massive Galaxies With Central Black Holes

  Astrophysics (arXiv)

Summary: Minor mergers of galaxies are expected to be common in a hierarchical cosmology such as $\\Lambda$CDM and have the potential to significantly affect galactic structure. In this paper we dissect the case-by-case outcome from a set of numerical simulations of a single satellite elliptical galaxy accreting onto a massive elliptical galaxy. We take care to explore cosmologically relevant orbital parameters and to set up realistic initial galaxy models that include all three relevant dynamical components: dark matter halos, stellar bulges, and central massive black holes. The effects of several different parameters are considered, including orbital energy and angular momentum, satellite density and inner density profile, satellite-to-host mass ratio, and presence of a black hole at the center of the host. Black holes play a crucial role in protecting the shallow stellar cores of the hosts, as satellites merging onto a host with a central black hole are more strongly disrupted than those merging onto hosts without black holes. Orbital parameters play an important role in determining the degree of disruption: satellites on less bound or more eccentric orbits are more easily destroyed than those on more bound or more circular orbits as a result of an increased number of pericentric passages and greater cumulative effects of gravitational shocking and tidal stripping. In addition, satellites with densities typical of faint elliptical galaxies are disrupted relatively easily, while denser satellites can survive much better in the tidal field of the host. Over the range of parameters explored, we find that the accretion of a single satellite elliptical galaxy can result in a broad variety of changes, in both signs, in the surface brightness profile and color of the central part of an elliptical galaxy.

Michael Boylan-Kolchin; Chung-Pei Ma
2006-11-17

364

Satellite-viewed cloud signatures associated with extratropical cyclogenesis

  Texas A&M University - TxSpace

Summary: SATELLITE-VIEWED CLOUD SIGNATURES ASSOCIATED WITH EXTRATROPICAL CYCLOGENESIS A Thesis by ROBERT LUCIEN LAPIERRE Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE May 1973 Major Subject: Meteorology SATELLITE-VIENED CLOUD SIGNATURES ASSOCIATED WITH EXTRATROPICAL CYCLOGENESIS A Thesis by ROBERT LUCIEN LAPIERRE Appi"o ed as to st~le and content by: n llcgrceo~& (C ai rman of Conmi t te~ YemberI Hay...

Lapierre, Robert Lucien
1973-01-01

365

Determination of wind from Nimbus-6 satellite sounding data

  Texas A&M University - TxSpace

Summary: 'ons of rawinsonde and satellite . onndings and surface wind observations in the Canada region Locations of rawinsonde and satellite soundings in the western United States recior. 12 Synoptic charts for the central United States region on 25 August 1975... . . . . . . . . . . . . . . . . . ~ 14 Synoptic charts for the Caribbean region Synoptic charts for the Canada region 15 16 synoptic charts for the western United States region on 3 September 1975 17 Computational grids and axes of cross sections 20 10 Profiles of the average...

Carle, William Everett
1979-01-01

366

Improvement of old reductions of irregular satellites using the first publications of the data

  Physics Websites

Summary: 111 Improvement of old reductions of irregular satellites using the first publications of the data plates made the discovery of additional natural satellites possible. The first satellite to be discovered in this manner, Phoebe, was found in 1899 by W.H. Pickering. A reliable model of satellite motion must

Paris-Sud XI, Université de

367

Long-Focus Astrometric Observations of the Planetary Satellites at USNO: 1967 2003

  Physics Websites

Summary: 59 Long-Focus Astrometric Observations of the Planetary Satellites at USNO: 1967 ­ 2003 Dan Pascu of long- focus observations of the planetary satellites made at the U.S. Naval Observatory (USNO) from refractor, targeted the Martian satellites, the Galilean moons of Jupiter and satellites I ­ VIII of Saturn

Paris-Sud XI, Université de

368

22nd AIAA International Communications Satellite Systems Conference & Exhibit 2004 9 -12 May 2004, Monterey, California

  Engineering Websites

Summary: 22nd AIAA International Communications Satellite Systems Conference & Exhibit 2004 9 -12 May 2004 supporting Internet and data servicesvia satellite. We study the characteristicsof an aeronautical satellite for the satellite link than end-to-end TCP, especiallyin high BER environment. 1 INTRODUCTION The popularity

Baras, John S.

369

Proactive TCP mechanism to improve Handover performance in Mobile Satellite and Terrestrial Networks

  Computer Technologies and Information Sciences Websites

Summary: Proactive TCP mechanism to improve Handover performance in Mobile Satellite and Terrestrial@gmail.com *Corresponding Author Abstract Emerging standardization of Geo Mobile Radio (GMR-1) for satellite system satellite and terrestrial networks. Keywords: Satellite-Terrestrial Network, Inter-system handover, TCP 1

Sanyal, Sugata

370

A SURVEY FOR OUTER SATELLITES OF MARS: LIMITS TO COMPLETENESS Scott S. Sheppard,1

  Physics Websites

Summary: A SURVEY FOR OUTER SATELLITES OF MARS: LIMITS TO COMPLETENESS Scott S. Sheppard,1 David Jewitt July 15 ABSTRACT We have surveyed the Hill sphere of Mars for irregular satellites. Our search covered the satellites Phobos and Deimos reside. No new satellites were found to an apparent limiting red magnitude of 23

Jewitt, David C.

371

Multispectral inverse problems in satellite image processing S. A. Starks and V. Kreinovich

  Computer Technologies and Information Sciences Websites

Summary: Multi­spectral inverse problems in satellite image processing S. A. Starks and V. Kreinovich NASA, TX 79968, USA ABSTRACT Satellite imaging is nowadays one of the main sources of geophysical image. This case corresponds to a single satellite photo. Existing satellites (e.g., Landsat) take

Kreinovich, Vladik

372

OPTIMAL DESPIN OF A TUMBLING SATELLITE WITH AN ARBITRARY THRUSTER CONFIGURATION, INERTIA MATRIX,

  Engineering Websites

Summary: satellite and fired remotely. If the tumbling satellite has a docking ring (such as on the Hubble Space, failed docking attempts, colli- sion with space debris, etc. In general, it cannot be assumed Telescope), a chaser satellite may rigidly dock with the tumbling satellite and then apply forces or torques


373

ROUTING IN LEO-BASED SATELLITE NETWORKS Vidyashankar V Gounder Ravi Prakash Hosame Abu-Amara

  Computer Technologies and Information Sciences Websites

Summary: strategies have been proposed for routing in a low earth orbit (LEO) satellite system. Some of them are based and Control Centers (NOCCs) required to support the satellite system. Keywords: low earth orbit satellite. INTRODUCTION Of late, low earth orbit (LEO) and medium earth orbit (MEO) based satellite networks have become

Prakash, Ravi

374

Cross-Layer Designs Architecture for LEO Satellite Ad Hoc Network

  Engineering Websites

Summary: Cross-Layer Designs Architecture for LEO Satellite Ad Hoc Network Zhijiang Chang and Georgi Orbit (LEO) satellite networks are envi- sioned as distributed architectures of autonomous data and data among ground stations and satellites mini- mizing delay and power. The LEO satellite networks

Kuzmanov, Georgi

375

Matching a photograph to satellite images Roger Grosse and Matthew Johnson

  Computer Technologies and Information Sciences Websites

Summary: it to satellite imagery. First, a user labels interest points in the pho- tograph corresponding to stationary to satellite imagery would have many exciting appli- cations. For example, it could serve as a tool to locate and the satellite imagery to be performed automatically, since the assumption is that the database of satellite

Willsky, Alan S.

376

TCP session analysis and modeling of hybrid satellite-terrestrial Internet

  Computer Technologies and Information Sciences Websites

Summary: TCP session analysis and modeling of hybrid satellite-terrestrial Internet traffic Savio Lau saviol University #12;April 25, 2006 BCNET Advanced Networks Conference: Hybrid satellite-terrestrial Internet Advanced Networks Conference: Hybrid satellite-terrestrial Internet traffic 3 Characteristics of satellite

Trajkovic, Ljiljana

377

Performance-aware Security of Unicast Communication in Hybrid Satellite Networks

  Engineering Websites

Summary: Performance-aware Security of Unicast Communication in Hybrid Satellite Networks Ayan Roy for securing the end-to-end communication in hybrid satellite networks. Satellite networks use TCP and HTTP communication in hybrid satellite networks. We therefore propose the use of the Layered IPSEC (LES) protocol

Baras, John S.

378

Achieving QoS for TCP traffic in Satellite Networks with Differentiated Services Arjan Durresi1

  Computer Technologies and Information Sciences Websites

Summary: intersatellite links, advanced link access methods and multicast technologies. Many new satellite communication. However, satellite systems have several inherent constraints. The resources of the satellite communication1 Achieving QoS for TCP traffic in Satellite Networks with Differentiated Services Arjan Durresi1

Durresi, Arjan

379

Embodied Social Proxy: Mediating Interpersonal Connection in Hub-and-Satellite Teams

  Computer Technologies and Information Sciences Websites

Summary: and satellite colleagues. ACM Classification Keywords H.4.3. Information systems and applications: CommunicationEmbodied Social Proxy: Mediating Interpersonal Connection in Hub-and-Satellite Teams Gina Venolia for one remote member. These "hub-and-satellite" teams face the challenge of the satellite colleague being

Rajamani, Sriram K.

380

Applicability and Performance of NEMO in Satellite Abu Zafar M. Shahriar

  Computer Technologies and Information Sciences Websites

Summary: for satellite communications [4]. Application of MIP to satellite networks has been proposed by Israel et al. [5Applicability and Performance of NEMO in Satellite Networks Abu Zafar M. Shahriar Mohammed}@ou.edu William Ivancic Satellite Networks and Architectures Branch NASA Glenn Research Center, Cleveland, OH

Atiquzzaman, Mohammed

381

SaVi satellite constellation visualization CCSR Research Symposium 2011 Lloyd Wood, Research Fellow

  Engineering Websites

Summary: SaVi satellite constellation visualization CCSR Research Symposium 2011 ­ Lloyd Wood, Research and coverage that results from multiple satellites orbiting to form a particular satellite constellation useful simulations of satellites and constellations for research and teaching purposes. System Model: Sa

Wood, Lloyd

382

The peculiar velocities of satellites of external disk galaxies

  Astrophysics (arXiv)

Summary: We analyze the angular distribution and the orbital rotation directions of a sample of carefully-selected satellite galaxies extracted from the Sloan Digital Sky Survey (SDSS). We also study these statistics in an N-body simulation of cosmological structure formation set within the LCDM paradigm under various assumptions for the orientations of disk angular momenta. Assuming that the angular momenta of the disks are aligned with the angular momenta of the inner regions of their host dark matter halos, we find that the fraction of simulated satellite halos that exhibit prograde motion is 0.55-0.60, with larger satellites more likely to be prograde. In our observational sample, approximately 60% of the satellites exhibit prograde motion, a result that is broadly consistent with the simulated sample. Contrary to several recent studies, our observational sample of satellite galaxies show no evidence for being anisotropically distributed about their primary disks. Again, this result is broadly consistent with our simulated sample of satellites under the assumption that disk and halo angular momenta are aligned. However, the small size of our observational sample does not yet allow us to distinguish between various assumptions regarding the orientations of disks in their halos. Finally, we assessed the importance of contamination by interlopers on the measured prograde and retrograde statistics.

M. Azzaro; A. R. Zentner; F. Prada; A. Klypin
2005-06-22

383

Planes of satellite galaxies and the cosmic web

  CERN Preprints

Summary: Recent observational studies have demonstrated that most satellite galaxies tend to orbit their hosts on highly flattened, vast, possibly co-rotating planes. Two nearly parallel planes of satellites have been confirmed around the M31 galaxy and around the Centaurus A galaxy, while the Milky Way also sports a plane of satellites. It has been argued that such an alignment of satellites on vast planes is unexpected in the standard ($\\Lambda$CDM) model of cosmology if not even in contradiction to its generic predictions. Guided by $\\Lambda$CDM numerical simulations, which suggest that satellites are channeled towards hosts along the axis of the slowest collapse as dictated by the ambient velocity shear tensor, we re-examine the planes of local satellites systems within the framework of the local shear tensor derived from the Cosmicflows-2 dataset. The analysis reveals that the Local Group and Centaurus A reside in a filament stretched by the Virgo cluster and compressed by the expansion of the Local Void. Four ou...

Libeskind, Noam I; Tully, R Brent; Courtois, Helene M; Pomarede, Daniel; Gottloeber, Stefan; Steinmetz, Matthias
2015-01-01

384

The Abundance and Radial Distribution of Satellite Galaxies

  Astrophysics (arXiv)

Summary: Using detailed mock galaxy redshift surveys (MGRSs) we investigate the abundance and radial distribution of satellite galaxies. The mock surveys are constructed using the conditional luminosity function (CLF), and are compared against data from the 2dFGRS. We use Monte Carlo Markov Chains to explore the full posterior distribution of the CLF parameter space, and show that the average relation between light and mass is tightly constrained. The radial number density distribution of satellite galaxies in the 2dFGRS reveals a pronounced absence of satellites at small projected separations from their host galaxies. This is (at least partially) due to the overlap and merging of galaxy images in the APM catalogue. Because of the resulting close-pair incompleteness we are unfortunately unable to put meaningful constraints on the radial distribution of satellite galaxies. Marginalizing over the full CLF parameter space, we show that in a LCDM concordance cosmology the observed abundances of host and satellite galaxies in the 2dFGRS indicate a power spectrum normalization of sigma_8=0.7. The same cosmology but with sigma_8=0.9 is unable to simultanously match the abundances of host and satellite galaxies. This confirms our previous conclusions based on the pairwise peculiar velocity dispersions and the group multipliticy function.

Frank C. van den Bosch; Xiaohu Yang; H. J. Mo; Peder Norberg
2004-06-09

385

Interactions of Satellite Galaxies in Cosmological Dark Matter Halos

  Astrophysics (arXiv)

Summary: We present a statistical analysis of the interactions between satellite galaxies in cosmological dark matter halos taken from fully self-consistent high-resolution simulations of galaxy clusters. We show that the number distribution of satellite encounters has a tail that extends to as many as 3-4 encounters per orbit. On average 30% of the substructure population had at least one encounter (per orbit) with another satellite galaxy. However, this result depends on the age of the dark matter host halo with a clear trend for more interactions in younger systems. We also report a correlation between the number of encounters and the distance of the satellites to the centre of the cluster: satellite galaxies closer to the centre experience more interactions. However, this can be simply explained by the radial distribution of the substructure population and merely reflects the fact that the density of satellites is higher in those regions. In order to find substructure galaxies we applied (and present) a new technique based upon the N-body code MLAPM. This new halo finder MHF (MLAPM's-Halo-Finder) acts with exactly the same accuracy as the N-body code itself and is therefore free of any bias and spurious mismatch between simulation data and halo finding precision related to numerical effects.

Alexander Knebe; Stuart P. D. Gill; Brad K. Gibson
2004-02-17

386

Heating of Galactic Disks by Infalling Satellites

  Astrophysics (arXiv)

Summary: We develop an analytic model to calculate the rate at which galaxy disks are heated by dark matter substructures orbiting in their halos. The model takes into account the internal structure, mass function and accretion rate of satellites expected in the LambdaCDM cosmology, as well as the growth of the disk by accretion and mergers, but it ignores resonant heating of the disk and the dynamical effects of spiral arms and bars. We calibrate this model against N-body simulations and demonstrate that it is able to reproduce the N-body heating rates to within a factor of 3 in the majority of cases. Our model gives the distribution of disk scale-heights for galaxies of different luminosities. For L* spiral galaxies, it predicts a median disk thickness of only 5% of the radial scale-length if substructure is the only source of heating. The median disk thickness increases to nearly 20% of the radial scale-length when heating due to gravitational scattering of stars by molecular clouds is also included. The latter value is close to the thickness estimated observationally for the disk of the Milky Way galaxy. The distribution of disk thickness predicted by the model is also consistent with a recent observational determination for sub-L* galaxies by Bizyaev & Mitronova. Thus, the observed thickness of the stellar disks of spiral galaxies seems to be entirely compatible with the abundance of substructure in dark matter halos predicted by the standard Lambda-dominated cold dark matter model of structure formation. In an Omega_0=1 universe, our best model of galaxy formation produces similar scale-heights, a consequence of the fact that similar amounts of substructure are accreted by halos during the lifetime of the disk in Omega_0=1 and Omega_0=0.3, Lambda_0=0.7 cold dark matter cosmologies.

A. J. Benson; C. G. Lacey; C. S. Frenk; C. G. Baugh; S. Cole
2004-03-18

387

Support of elastic TCP traffic over broadband geostationary satellite networks

  CiteSeer

Summary: The last decade has seen the clear dominance of the Internet Protocol in the data communication networks. Although the killer applications have changed significantly during this time, from file transfer and email to Web browsing and ?more recently? to file sharing, TCP has been consistently responsible for the overwhelming majority of Internet traffic. More significantly, recent protocol design efforts within the Internet community adopt fundamental features of the protocol, strongly suggesting that TCP and TCP-like traffic will continue contributing the majority of Internet data traffic, at least in the short-term future. Given the clear IP dominance, broadband satellite networks may be viewed as yet another subnet over which the TCP/IP suite, in general, and TCP traffic in particular, have to be efficiently supported. In this Thesis, we investigate issues relevant to the support of elastic TCP traffic over satellite networks. We focus our attention on geostationary satellite networks, which have almost monopolized the interest of satcom community the last decade, in light of the high risks and investment involved in the development of satellite constellations. We investigate mechanisms available at the satellite network for the provision of service differentiation to TCP flows. We demonstrate that fundamental satellite access network capabilities provide enough flexibility for the provision of qualitative service differentiation for TCP flows over these networks without necessitating per-flow state at the MAC layer and/or the computational overhead of prediction methods that are not straightforward for TCP traffic. Moreover, the split-TCP mechanism, despite the security-related and reliability-related concerns it raises, provides the network operator with significant additional flexibility in the treatment of TCP traffic. The mechanism forms a transport-layer differentiation mechanism that, when combined with lower-layer capabilities, can give rise to separate bearer services over the satellite network. We make two contributions to the study of the split-TCP concept. The first contribution is an analytical model for the estimation of split-TCP latency and the buffer requirements at the intermediate node that hosts the split-TCP agent. The second contribution is a split-TCP scheme, called split-Delayed Duplicate Acknowledgments (split-DDA), which draws heavily on DDA, a TCP variant presented and evaluated earlier as an end-to-end scheme in the context of terrestrial wireless networks. The provision of quantitative Quality-of-Service guarantees to TCP flows necessitates some form of access control to the satellite network and the presence of TCP performance enhancing proxy agents can assist this task significantly. We present and evaluate a heuristic implicit admission control algorithm for TCP flows over split-TCP satellite networks that can preserve the target requirements in terms of TCP steady-state throughput and TCP latency. We describe generic fixed-point approximations for the performance of TCP flows in geostationary satellite networks. We provide examples for the method applicability to various satellite network configurations evaluate the method against simulation results in the context of MAC-shared satellite links with dynamic bandwidth allocation mechanisms and discuss its strong and weak points. The utility of these approximations is further demonstrated in the case of the algorithm we introduce for the dynamic control of the TCP maximum receive window variable in split-TCP satellite networks. The algorithm accelerates TCP transfers at low load without overloading unnecessarily the MAC buffers at high load. Finally, as an addendum, we provide a case study of Web browsing over bandwidth on demand satellite links. Spanning three layers, namely application, transport and access layers, the study demonstrates the impact of the radio interface mechanisms upon the performance perceived at the application layer.

Merkourios Karaliopoulos
2004-01-01

388

Workshop on Satellites for Solar Energy Resource Information -Washington, DC, April 10-11, 1996 POTENTIALS OF IMAGES FROM GEOSTATIONARY SATELLITE DATA FOR THE

  Physics Websites

Summary: Workshop on Satellites for Solar Energy Resource Information - Washington, DC, April 10-11, 1996 POTENTIALS OF IMAGES FROM GEOSTATIONARY SATELLITE DATA FOR THE ASSESSMENT OF SOLAR ENERGY PARAMETERS Lucien Author manuscript, published in "Workshop `satellites for solar energy resource information', Washington

Paris-Sud XI, Université de

389

Dwarf Galaxy Clustering and Missing Satellites

  Astrophysics (arXiv)

Summary: At redshifts around 0.1 the CFHT Legacy Survey Deep fields contain some 6x10^4 galaxies spanning the mass range from 10^5 to 10^12 Msun. We measure the stellar mass dependence of the two point correlation using angular measurements to largely bypass the errors, approximately 0.02 in the median, of the photometric redshifts. Inverting the power-law fits with Limber's equation we find that the auto-correlation length increases from a very low 0.4hMpc at 10^5.5 Msun to the conventional 4.5hMpc at 10^10.5 Msun. The power law fit to the correlation function has a slope which increases from gamma approximately 1.6 at high mass to gamma approximately 2.3 at low mass. The spatial cross-correlation of dwarf galaxies with more massive galaxies shows fairly similar trends, with a steeper radial dependence at low mass than predicted in numerical simulations of sub-halos within galaxy halos. To examine the issue of missing satellites we combine the cross-correlation measurements with our estimates of the low mass galaxy number density. We find on the average there are 60+/-20 dwarfs in sub-halos with M(total) > 10^7 Msun for a typical Local Group M(total)/M(stars)=30, corresponding to M/L_V approximately 100 for a galaxy with no recent star formation. The number of dwarfs per galaxy is about a factor of two larger than currently found for the Milky Way. Nevertheless, the average dwarf counts are about a factor of 30 below LCDM simulation results. The divergence from LCDM predictions is one of slope of the relation, approximately dN/dlnM approximately -0.5 rather than the predicted -0.9, not sudden onset at some characteristic scale. The dwarf galaxy star formation rates span the range from passive to bursting, which suggests that there are few completely dark halos.

R. G. Carlberg; M. Sullivan; D. Le Borgne
2008-12-16

390

Stability of Satellites Around Close-in Extrasolar Giant Planets

  Astrophysics (arXiv)

Summary: We investigate the long-term dynamical stability of hypothetical moons orbiting extrasolar giant planets. Stellar tides brake a planet's rotation and, together with tidal migration, act to remove satellites; this process limits the lifetimes of larger moons in extrasolar planetary systems. Because more massive satellites are removed more quickly than less massive ones, we are able to derive an upper mass limit for those satellites that might have survived to the present day. For example, we estimate that no primordial satellites with masses greater than 7 x 10^{-7} M_Earth$ (~ \\70km radius for rho=3 g cm^{-3}) could have survived around the transiting planet HD209458b for the age of the system. No meaningful mass limits can be placed on moons orbiting Jovian planets more than ~0.6 AU from their parent stars. Earth-like moons of Jovian planets could exist for 5 Gyr in systems where the stellar mass is greater than 0.15 M_Sun. Transits show the most promise for the discovery of extrasolar moons -- we discuss prospects for satellite detection via transits using space-based photometric surveys and the limits on the planetary tidal dissipation factor Q that a discovery would imply.

Jason W. Barnes; D. P. O'Brien
2002-05-02

391

Satellite Galaxies and Fossil Groups in the Millennium Simulation

  Astrophysics (arXiv)

Summary: We use a semianalytic galaxy catalogue constructed from the Millennium Simulation to study the satellites of isolated galaxies in the LCDM cosmogony. This sample (~80,000$ bright primaries, surrounded by ~178,000 satellites) allows the characterization, with minimal statistical uncertainty, of the dynamical properties of satellite/primary galaxy systems in a LCDM universe. We find that, overall, the satellite population traces the dark matter rather well: its spatial distribution and kinematics may be approximated by an NFW profile with a mildly anisotropic velocity distribution. Their spatial distribution is also mildly anisotropic, with a well-defined ``anti-Holmberg'' effect that reflects the misalignment between the major axis and angular momentum of the host halo. The isolation criteria for our primaries picks not only galaxies in sparse environments, but also a number of primaries at the centre of ''fossil'' groups. We find that the abundance and luminosity function of these unusual systems are in reasonable agreement with the few available observational constraints. We recover the expected L_{host} \\sigma_{sat}^3 relation for LCDM models for truly-isolated primaries. Less strict primary selection, however, leads to substantial modification of the scaling relation. Our analysis also highlights a number of difficulties afflicting studies that rely on blind stacking of satellite systems to constrain the mean halo mass of the primary galaxies.

L. V. Sales; J. F. Navarro; D. G. Lambas; S. D. M. White; D. J. Croton
2007-09-27

392

Tidal disruption of satellites and formation of narrow rings

  CERN Preprints

Summary: In this paper we investigate the formation of narrow planetary rings such as those found around Uranus and Saturn through the tidal disruption of a weak, gravitationally bound satellite that migrates within its Roche limit. Using $N$-body simulations, we study the behaviour of rubble piles placed on circular orbits at different distances from a central planet. We consider both homogeneous satellites and differentiated bodies containing a denser core. We show that the Roche limit for a rubble pile is closer to the planet than for a fluid body of the same mean density. The Roche limit for a differentiated body is also closer to the planet than for a homogeneous satellite of the same mean density. Within its Roche limit, a homogeneous satellite totally disrupts and forms a narrow ring. The initial stages of the disruption are similar to the evolution of a viscous fluid ellipsoid, which can be computed semi-analytically. On the other hand, when a differentiated satellite is just within the Roche limit only the ma...

Leinhardt, Zoe M; Latter, Henrik N; Kokubo, Eiichiro
2012-01-01

393

Disentangling satellite galaxy populations using orbit tracking in simulations

  CERN Preprints

Summary: Physical processes regulating star formation in satellite galaxies represent an area of ongoing research, but the projected nature of observed coordinates makes separating different populations of satellites (with different processes at work) difficult. The orbital history of a satellite galaxy leads to its present-day phase space coordinates; we can also work backwards and use these coordinates to statistically infer information about the orbital history. We use merger trees from the MultiDark Run 1 N-body simulation to compile a catalog of the orbits of satellite haloes in cluster environments. We parameterize the orbital history by the time since crossing within 2.5 rvir of the cluster centre and use our catalog to estimate the probability density over a range of this parameter given a set of present-day projected (i.e. observable) phase space coordinates. We show that different populations of satellite haloes, e.g. infalling, backsplash and virialized, occupy distinct regions of phase space, and semi-dist...

Oman, Kyle A; Behroozi, Peter S
2013-01-01

394

A census of orbital properties of the M31 satellites

  CERN Preprints

Summary: We present an analysis of the dynamics of the M31 satellite system. Proper motion data exist for only two of the M31 satellites. We account for this incompleteness in velocity data by a statistical analysis using a combination of the timing argument and phase-space distribution functions. The bulk of the M31 satellites are well fit by these models and we offer a table of orbital properties, including period, eccentricity and semi-major axis. This enables us to search for evidence of group infall based on orbital similarity rather than propinquity on the sky. Our results favour an association between Cass II and NGC 185, as the orbital parameters are in close agreement, but not for NGC 185 and NGC 147, which have often been associated in the past. Other possible satellite groupings include the pair And I and And XVII; the pair And IX and And X; and the triple And V, And XXV and NGC 147. And XXII has been claimed as a satellite of M33; we find that they are not moving independently along the same orbit, but can...

Watkins, Laura L; van de Ven, Glenn
2012-01-01

395

The colors of satellite galaxies in the Illustris Simulation

  CERN Preprints

Summary: Observationally, the fraction of blue satellite galaxies decreases steeply with host halo mass, and their radial distribution around central galaxies is significantly shallower in massive (M_* >10e11M_sun) than in Milky Way like systems. Theoretical models, based primarily on semi-analytical techniques, have had a long-standing problem with reproducing these trends, instead predicting too few blue satellites in general but also estimating a radial distribution that is too shallow, regardless of primary mass. In this Letter, we use the Illustris cosmological simulation to study the properties of satellite galaxies around isolated primaries. For the first time, we find good agreement between theory and observations. We identify the main source of this success relative to earlier work to be a consequence of the large gas contents of satellites at infall, a factor ~5-10 times larger than in semi-analytical models. Because of their relatively large gas reservoirs, satellites can continue to form stars long after i...

Sales, Laura V; Genel, Shy; Torrey, Paul; Nelson, Dylan; Rodriguez-Gomez, Vicente; Wang, Wenting; Pillepich, Annalisa; Sijacki, Debora; Springel, Volker; Hernquist, Lars
2014-01-01

396

Dark-matter decays and Milky Way satellite galaxies

  HEP - Phenomenology (arXiv)

Summary: We consider constraints on a phenomenological dark-matter model consisting of two nearly degenerate particle species using observed properties of the Milky Way satellite galaxy population. The two parameters of this model, assuming the particle masses are >~ GeV, are v_k, the recoil speed of the daughter particle, and tau, the lifetime of the parent particle. The satellite constraint that spans the widest range of v_k is the number of satellites that have a mass within 300 pc M300 > 5 x 10^6 solar masses, although constraints based on M300 in the classical dwarfs and the overall velocity function are competitive for v_k >~ 50 km/s. In general, we find that tau <~ 30 Gyr is ruled out for 20 km/s <~ v_k <~ 200 km/s, although we find that the limits on tau for fixed v_k can change constraints by a factor of ~3 depending on the star-formation histories of the satellites. We advocate using the distribution of M300 in Milky Way satellites determined by next-generation all-sky surveys and follow-up spectroscopy as a probe of dark-matter properties.

Annika H. G. Peter; Andrew J. Benson
2010-09-09

397

The Rise and Fall of Satellites in Galaxy Clusters

  Astrophysics (arXiv)

Summary: We use N-body simulations to study the infall of dark matter haloes onto rich clusters of galaxies. After identification of all cluster progenitors in the simulations, we select those haloes which accrete directly onto the main cluster progenitor. We construct the mass function of these merging satellites, and calculate the main orbital parameters for the accreted lumps. The average circularity of the orbits is epsilon = 0.5, while either radial or almost circular orbits are equally avoided. More massive satellites move along slightly more eccentric orbits, with lower specific angular momentum and a smaller pericentre. We find that the infall of satellites onto the main cluster progenitor has a very anisotropic distribution. This anisotropy is to a large extent responsible for the shape and orientation of the final cluster and of its velocity ellipsoid. At the end of the simulations, the major axis of the cluster is aligned both with that of its velocity ellipsoid, and with the major axis of the ellipsoid defined by the satellite infall pattern, to 30 degrees on average. We also find that, in lower mass clusters, a higher fraction of the final virial mass is provided by small, dense satellites. These sink to the centre of the parent cluster and so enhance its central density. This mechanism is found to be partially responsible for the correlation between halo masses and characteristic overdensities, recently highlighted by Navarro, Frenk & White (1996).

Giuseppe Tormen
1998-02-23

398

Disruption of Dwarf Satellite Galaxies without Dark Matter

  CERN Preprints

Summary: The evolution of a satellite galaxy of a Milky Way like galaxy has been studied using N-Body simulations. The initial satellites, containing one million particles, have been simulated by a Plummer sphere, while the potential of the host galaxy is a three component rigid potential: disc, bulge and dark matter halo. It has been found that several orbits of the satellites allow for the existence, for about 1 Gyr or more, of an out-of-equilibrium body that could be interpreted as a dSph satellite galaxy of the Milky Way. In addition, from the study of the evolution of the mass-to-light ratios of satellites that show a disrupted phase it has been found that it is possible that some dSph galaxies of the Milky Way with large M/L ratios might not be dark matter dominated and that their high mass to light ratios are observed because they are out of equilibrium objects.

Casas, Rigoberto A
2011-01-01

399

Spectroscopic confirmation of hydrogen alpha-selected satellite galaxies

  CERN Preprints

Summary: We present a spectroscopic test confirming the potential of narrow-band optical imaging as a method for detecting star-forming satellites around nearby galaxies. To date the efficiency of such methods, and particularly the fraction of false detections resulting from its use, has not been tested. In this paper we use optical spectroscopy to verify the nature of objects that are apparently emission-line satellites, taken from imaging presented elsewhere. Observations of 12 probable satellites around 11 host galaxies are presented and used to compare the recession velocities of the host and satellite. This test confirms, in all cases, that there is genuine line emission, that the detected line is hydrogen alpha, and that the satellites have similar recession velocities to their hosts with a maximum difference of ~ 250 km/s, consistent with their being gravitationally bound companions. We conclude that the spectroscopy has confirmed that narrow-band imaging through H alpha filters is a reliable method for detecti...

Ivory, Clare F
2010-01-01

400

The Luminosity Function of the Milky Way Satellites

  Astrophysics (arXiv)

Summary: We quantify the detectability of stellar Milky Way satellites in the Sloan Digital Sky Survey (SDSS) Data Release 5. We show that the effective search volumes for the recently discovered SDSS--satellites depend strongly on their luminosity, with their maximum distance, $D_{max}$, substantially smaller than the Milky Way halo's virial radius. Calculating the maximum accessible volume, $V_{max}$, for all faint detected satellites, allows the calculation of the luminosity function for Milky Way satellite galaxies, accounting quantitatively for their detectability. We find that the number density of satellite galaxies continues to rise towards low luminosities, but may flatten at $M_V \\sim -5$; within the uncertainties, the luminosity function can be described by a single power law $dN/dM_{V}= 10 \\times 10^{0.1 (M_V+5)}$, spanning luminosities from $M_V=-2$ all the way to the luminosity of the Large Magellanic Cloud. Comparing these results to several semi-analytic galaxy formation models, we find that their predictions differ significantly from the data: either the shape of the luminosity function, or the surface brightness distributions of the models, do not match.

S. Koposov; V. Belokurov; N. W. Evans; P. C. Hewett; M. J. Irwin; G. Gilmore; D. B. Zucker; H. -W. Rix; M. Fellhauer; E. F. Bell; E. V. Glushkova
2008-05-19

401

Orbital Perturbations of the Galilean Satellites During Planetary Encounters

  CERN Preprints

Summary: The Nice model of the dynamical instability and migration of the giant planets can explain many properties of the present Solar System, and can be used to constrain its early architecture. In the jumping-Jupiter version of the Nice model, required from the terrestrial planet constraint and dynamical structure of the asteroid belt, Jupiter has encounters with an ice giant. Here we study the survival of the Galilean satellites in the jumping-Jupiter model. This is an important concern because the ice-giant encounters, if deep enough, could dynamically perturb the orbits of the Galilean satellites, and lead to implausible results. We performed numerical integrations where we tracked the effect of planetary encounters on the Galilean moons. We considered three instability cases from Nesvorny & Morbidelli (2012) that differed in the number and distribution of encounters. We found that in one case, where the number of close encounters was relatively small, the Galilean satellite orbits were not significantly af...

Deienno, R; Vokrouhlicky, D; Yokoyama, T
2014-01-01

402

Secure Satellite Communication Systems Design with Individual Secrecy Rate Constraints

  CERN Preprints

Summary: In this paper, we study multibeam satellite secure communication through physical (PHY) layer security techniques, i.e., joint power control and beamforming. By first assuming that the Channel State Information (CSI) is available and the beamforming weights are fixed, a novel secure satellite system design is investigated to minimize the transmit power with individual secrecy rate constraints. An iterative algorithm is proposed to obtain an optimized power allocation strategy. Moreover, sub-optimal beamforming weights are obtained by completely eliminating the co-channel interference and nulling the eavesdroppers' signal simultaneously. In order to obtain jointly optimized power allocation and beamforming strategy in some practical cases, e.g., with certain estimation errors of the CSI, we further evaluate the impact of the eavesdropper's CSI on the secure multibeam satellite system design. The convergence of the iterative algorithm is proven under justifiable assumptions. The performance is evaluated by taki...

Lei, Jiang; Vázquez-Castro, M A; Hjørungnes, Are
2011-01-01

403

Operational Satellite Monitoring Systems for Marine Oil and Gas Industry

  CiteSeer

Summary: Abstract- Shipping activities, oil production and transport in the sea, oil handled in harbors, construction of oil and gas pipelines have a number of negative impacts on the marine environment and coastal zone. We elaborated several operational satellite monitoring systems for oil and gas companies in Russia and performed complex satellite monitoring of the ecological state of coastal waters, which included oil pollution, suspended matter, and algae bloom, in a fully operational regime. Our experience includes: (1) monitoring of the Lukoil D-6 oil rig in the southeastern Baltic Sea in 2004-2005; (2) monitoring of the underwater gas pipeline “Dzhubga-Lazarevskoe-Sochi ” construction in the eastern Black Sea (2010); (3) monitoring of the “Nord Stream ” underwater gas pipeline construction in the Baltic Sea (2010); (4) elaboration of the structure and principles of the complex satellite monitoring system organization for all coastal seas of Russia (2009-2010).

A. G. Kostianoy A; D. M. Solovyov B

404

On the nature of the Milky Way satellites

  CERN Preprints

Summary: We combine a series of high-resolution simulations with semi-analytic galaxy formation models to follow the evolution of a system resembling the Milky Way and its satellites. The semi-analytic model is based on that developed for the Millennium Simulation, and successfully reproduces the properties of galaxies on large scales, as well as those of the Milky Way. In this model, we are able to reproduce the luminosity function of the satellites around the Milky Way by preventing cooling in haloes with Vvir 10 Gyr, and a few of them formed most of their stars before the reionization was complete. Objects with luminosities comparable to those of the classical MW satellites are associated with dark matter subhaloes with a peak circular velocity $\\gta$ 10 km/s, in agreement with the latest constraints.

Li, Yang-Shyang; Helmi, Amina
2009-01-01

405

Channel Estimation And Multiuser Detection In Asynchronous Satellite Communications

  CERN Preprints

Summary: In this paper, we propose a new method of channel estimation for asynchronous additive white Gaussian noise channels in satellite communications. This method is based on signals correlation and multiuser interference cancellation which adopts a successive structure. Propagation delays and signals amplitudes are jointly estimated in order to be used for data detection at the receiver. As, a multiuser detector, a single stage successive interference cancellation (SIC) architecture is analyzed and integrated to the channel estimation technique and the whole system is evaluated. The satellite access method adopted is the direct sequence code division multiple access (DS CDMA) one. To evaluate the channel estimation and the detection technique, we have simulated a satellite uplink with an asynchronous multiuser access.

Chaouech, Helmi; 10.5121/ijwmn.2010.2411
2010-01-01

406

A Curious New Milky Way Satellite in Ursa Major

  Astrophysics (arXiv)

Summary: In this Letter, we study a localized stellar overdensity in the constellation of Ursa Major, first identified in Sloan Digital Sky Survey (SDSS) data and subsequently followed up with Subaru imaging. Its color-magnitude diagram (CMD) shows a well-defined sub-giant branch, main sequence and turn-off, from which we estimate a distance of ~30 kpc and a projected size of ~250 x 125 pc. The CMD suggests a composite population with some range in metallicity and/or age. Based on its extent and stellar population, we argue that this is a previously unknown satellite galaxy of the Milky Way, hereby named Ursa Major II (UMa II) after its constellation. Using SDSS data, we find an absolute magnitude of M_V \\~ -3.8, which would make it the faintest known satellite galaxy. UMa II's isophotes are irregular and distorted with evidence for multiple concentrations; this suggests that the satellite is in the process of disruption.

D. B. Zucker; V. Belokurov; N. W. Evans; J. T. Kleyna; M. J. Irwin; M. I. Wilkinson; M. Fellhauer; D. M. Bramich; G. Gilmore; H. J. Newberg; B. Yanny; J. A. Smith; P. C. Hewett; E. F. Bell; H. -W. Rix; O. Y. Gnedin; S. Vidrih; R. F. G. Wyse; B. Willman; E. K. Grebel; D. P. Schneider; T. C. Beers; A. Y. Kniazev; J. C. Barentine; H. Brewington; J. Brinkmann; M. Harvanek; S. J. Kleinman; J. Krzesinski; D. Long; A. Nitta; S. A. Snedden
2006-07-04

407

The Three-Dimensional Structure of the M31 Satellite System; Strong Evidence for an Inhomogeneous Distribution of Satellites

  CERN Preprints

Summary: We undertake an investigation into the spatial structure of the M31 satellite system utilizing the distance distributions presented in a previous publication. These distances make use of the unique combination of depth and spatial coverage of the Pan-Andromeda Archaeological Survey (PAndAS) to provide a large, homogeneous sample consisting of 27 of M31's satellites, as well as M31 itself. We find that the satellite distribution, when viewed as a whole, is no more planar than one would expect from a random distribution of equal size. A disk consisting of 15 of the satellites is however found to be highly significant, and strikingly thin, with a root-mean-square thickness of just $12.34^{+0.75}_{-0.43}$ kpc. This disk is oriented approximately edge on with respect to the Milky Way and almost perpendicular to the Milky Way disk. It is also roughly orthogonal to the disk like structure regularly reported for the Milky Way satellite system and in close alignment with M31's Giant Stellar Stream. A similar analysis ...

Conn, Anthony R; Ibata, Rodrigo A; Parker, Quentin A; Zucker, Daniel B; McConnachie, Alan W; Martin, Nicolas F; Valls-Gabaud, David; Tanvir, Nial; Irwin, Michael J; Ferguson, Annette M N; Chapman, Scott C
2013-01-01

408

Modeling the Jovian subnebula: II - Composition of regular satellites ices

  Astrophysics (arXiv)

Summary: We use the evolutionary turbulent model of Jupiter's subnebula described by Alibert et al. (2005a) to constrain the composition of ices incorporated in its regular icy satellites. We consider CO2, CO, CH4, N2, NH3, H2S, Ar, Kr, and Xe as the major volatile species existing in the gas-phase of the solar nebula. All these volatile species, except CO2 which crystallized as a pure condensate, are assumed to be trapped by H2O to form hydrates or clathrate hydrates in the solar nebula. Once condensed, these ices were incorporated into the growing planetesimals produced in the feeding zone of proto-Jupiter. Some of these solids then flowed from the solar nebula to the subnebula, and may have been accreted by the forming Jovian regular satellites. We show that ices embedded in solids entering at early epochs into the Jovian subdisk were all vaporized. This leads us to consider two different scenarios of regular icy satellites formation in order to estimate the composition of the ices they contain. In the first scenario, icy satellites were accreted from planetesimals that have been produced in Jupiter's feeding zone without further vaporization, whereas, in the second scenario, icy satellites were accreted from planetesimals produced in the Jovian subnebula. In this latter case, we study the evolution of carbon and nitrogen gas-phase chemistries in the Jovian subnebula and we show that the conversions of N2 to NH3, of CO to CO2, and of CO to CH4 were all inhibited in the major part of the subdisk. Finally, we assess the mass abundances of the major volatile species with respect to H2O in the interiors of the Jovian regular icy satellites. Our results are then compatible with the detection of CO2 on the surfaces of Callisto and Ganymede and with the presence of NH3 envisaged in subsurface oceans within Ganymede and Callisto.

Olivier Mousis; Yann Alibert
2005-10-28

409

Dwarf Spheroidal Satellite Galaxies and the Galactic Tidal Field

  Astrophysics (arXiv)

Summary: The Milky Way is surrounded by nine or more dwarf-spheroidal (dSph) satellite galaxies that appear to consist primarily of dark matter. Here I summarise research that shows that initially spherical bound low-mass satellites without dark matter, that are on orbits within a massive Galactic dark corona, can evolve into remnants that are non-spherical, have a non-isotropic velocity dispersion tensor and are not in virial equilibrium, but are bright enough for sufficiently long times to be mistaken for dark-matter dominated dSph galaxies.

Pavel Kroupa
1996-12-03

410

Silicon avalanche photodiode operation and lifetime analysis for small satellites

  Quantum Physics (arXiv)

Summary: Silicon avalanche photodiodes (APDs) are sensitive to operating temperature fluctuations and are also susceptible to radiation flux expected in satellite-based quantum experiments. We introduce a low power voltage adjusting mechanism to overcome the effects of in-orbit temperature fluctuations. We also present data on the performance of Si APDs after irradiation (gamma-ray and proton beam). Combined with an analysis of expected orbital irradiation, we propose that a Si APD in a 400 km equatorial orbit may operate beyond the lifetime of the satellite.

Yue Chuan Tan; Rakhitha Chandrasekara; Cliff Cheng; Alexander Ling
2013-06-28

411

Measuring Time of Flight Using Satellite-Based Clocks

  Physics (arXiv)

Summary: Considering the OPERA neutrino-velocity measurement from the point of view of a GPS satellite we find that the detector at Gran Sasso has a velocity component in the order of $10^{-5}c$ towards the neutrino emission location at CERN. On GPS-receivers this translates into first-order Doppler terms, therefore a correction is required for, among other things, this ephemeris-and-location-dependent relativistic effect. To ensure correct time-of-flight measurements using satellite-based clocks we propose to extend their calibration procedures with an explicit check on these relativistic corrections.

Ronald A. J. van Elburg
2011-11-18

412

Recent Improvements in Testing General Relativity with Satellite Laser Ranging

  General Relativity & Quantum Cosmology (arXiv)

Summary: In this work some aspects of the detection of certain general relativistic effects in the weak gravitational field of the Earth via laser-ranged data to some existing or proposed geodetic satellites are examined. The focus is on the Lense-Thirring drag of the orbit of a test body, the gravitomagnetic clock effect and the gravitoelectric perigee shift. The impact of some sources of systematic errors is investigated. An experiment whose goal is the measurement of the PPN parameters beta and gamma in the terrestrial field with LAGEOS satellites at a level of 10^(-3)is presented. A modified version of the proposed LARES mission is examined.

Lorenzo Iorio
2002-05-22

413

Searching for Tidal Tails in Galactic Dwarf Spheroidal Satellites

  Astrophysics (arXiv)

Summary: We present preliminary results of a long-term project to investigate the process of accretion and tidal disruption of dSph satellites in the Galactic halo and, in particular, to search for new tidal tails in a sample of nearby dSph satellites of the Milky Way. Here we present our finding of extra-tidal debris in the Ursa Minor dS ph and discuss the detection by the Sloan Digitized Sky Survey team of what could be a tidal stream associated to the Sagittarius dSph.

D. Martinez-Delgado; A. Aparicio; M. A. Gomez-Flechoso
2000-09-05

414

Research on the Satellite Networks Management Based on Policies

  CiteSeer

Summary: Abstract. According to structure feature of satellite network management, the global policy servers and the local policy servers have been established. Function modules of satellite networks were designed on the base of system architecture, such as policy management tools, policy library, policy decision point and policy execution point, etc. The policy description method based on XML has been implemented and policy decision point LDAP communication module and COPS communication module have been intensive studied. The policy transmission has been implemented among the policy management tools, the policy library and policy decision poinst through LDAP module and the transmission between the policy decision points and policy implementation points were also implemented by COPS.

Wenbo Zhang; Deyu Zhang

415

Satellite design parameters for detecting coherence in the microwave sky

  Astrophysics (arXiv)

Summary: Recently it has been realized that observations of fluctuations in the cosmic microwave background (CMB) can reveal very interesting information about the degree of coherence exhibited by the perturbations at early times. This fact should allow sufficiently detailed observations to clearly differentiate among several competing models of structure formation. We study the mission parameters required for a satellite to address the issue of coherence. Our results emphasize the importance of a small beamwidth, and support the cases for the PSI, FIRE and COBRAS/SAMBA satellite proposals (in increasing order of resolving power). Design parameters for a fourth proposal, MAP, have not been made available.

Andreas Albrecht; Benjamin D. Wandelt
1996-02-22

416

Mismatch and Misalignment: Dark Haloes and Satellites of Disc Galaxies

  CERN Preprints

Summary: (Abridged) We study the phase-space distribution of satellite galaxies associated with late-type galaxies in the GIMIC suite of simulations. GIMIC consists of re-simulations of 5 cosmologically representative regions from the Millennium simulation, which have higher resolution and incorporate baryonic physics. Whilst the disc of the galaxy is well aligned with the inner regions (r ~ 0.1r_200) of the dark matter halo, both in shape and angular momentum, there can be substantial misalignments at larger radii (r ~ r_200). Misalignments of > 45 deg are seen in ~ 30% of our sample. We find that the satellite population aligns with the shape (and angular momentum) of the outer dark matter halo. However, the alignment with the galaxy is weak owing to the mismatch between the disc and dark matter halo. Roughly 20% of the satellite systems with ten bright galaxies within r_200 exhibit a polar spatial alignment with respect to the galaxy --- an orientation reminiscent of the classical satellites of the Milky Way. We fi...

Deason, A J; Font, A; Evans, N W; Frenk, C S; Belokurov, V; Libeskind, N I; Crain, R A; Theuns, T
2011-01-01

417

Physical properties underlying observed kinematics of satellite galaxies

  CERN Preprints

Summary: We study the kinematics of satellites around isolated galaxies selected from the Sloan Digital Sky Survey (SDSS) spectroscopic catalog. Using a model of the phase-space density previously measured for the halos of LCDM dark matter cosmological simulations, we determine the properties of the halo mass distribution and the orbital anisotropy of the satellites as a function of the colour-based morphological type and the stellar mass of the central host galaxy. We place constraints on the halo mass and the concentration parameter of dark matter and the satellite number density profiles. We obtain a concentration-mass relation for galactic dark matter haloes that is consistent with predictions of a standard LCDM cosmological model. The number density profile of the satellites appears to be shallower than of dark matter, with the scale radius typically 1.6 times larger than of dark matter. The orbital anisotropy around red hosts exhibits a mild excess of radial motions, in agreement with the typical anisotropy prof...

Wojtak, Radoslaw
2012-01-01

418

Performance Comparison of DAMA MAC Schemes over Satellite Networks

  Computer Technologies and Information Sciences Websites

Summary: in partial fulfillment of the requirements for the degree of Master of Technology by Kalyan Rao D Roll No over Satellite Networks By Kalyan Rao D (02329023) is approved for the degree of Master of Technology suggestions and helpful discussions. Kalyan Rao D IIT Bombay July 9, 2004 vi #12;Contents Abstract v

Iyer, Sridhar

419

ANALYZING TIME SERIES OF SATELLITE IMAGERY USING TEMPORAL MAP ALGEBRA

  Environmental Sciences and Ecology Websites

Summary: components analysis and spectral analysis (e.g. Eastman and Fulk, 1993; Jakubauskus et al., 2001 analysis functions based on temporal map algebra. The temporal map algebra functions treat time series of temporal map algebra for time series satellite image analysis, we investigate the impact of El Niño

Mennis, Jeremy

420

Adaptive Satellite Attitude Control in the Presence of

  Engineering Websites

Summary: Adaptive Satellite Attitude Control in the Presence of Inertia and CMG Gimbal Friction matrix and unknown dynamic and static friction effects in the control moment gyroscope (CMG) gimbals friction effects and is embedded in a discontinuous nonlinearity due to static friction effects

Dixon, Warren

421

Satellite interferometric observations of displacements associated with seasonal groundwater

  Geosciences Websites

Summary: Satellite interferometric observations of displacements associated with seasonal groundwater in the elevation of the water table. We confirm this hypothesis through the analysis of a longer span of data, which is consistent with water table measurements as well as with the end of the rainy season when

Sandwell, David T.

422

Second Annual RECOMB Satellite Workshop on Computational Cancer Biology

  Computer Technologies and Information Sciences Websites

Summary: Second Annual RECOMB Satellite Workshop on Computational Cancer Biology Poster List 1. Eldrid Kåresen, Torill Sauer and Anne-Lise Børresen-Dale microRNAs involved in ischemic stress response of breast cancer tissue 2. Mike Smith, Mark Dunning, Simon Tavaré and Andy Lynch Identification and correction

Shamir, Ron

423

A Satellite Survey Cloud Cover and Water Vapor

  Physics Websites

Summary: A Satellite Survey of Cloud Cover and Water Vapor in Northern Chile A study conducted for: Cerro;EXECUTIVE SUMMARY Cloud cover and water vapor conditions in Northern Chile have been surveyed using fifty. An aerial mapping of cloud and water vapor has resulted in the identification of preferred areas


424

The Generalized Information Network Analysis Methodology for Distributed Satellite Systems

  CiteSeer

Summary: A systematic analysis methodology for distributed satellite systems is developed that is generalizable and can be applied to any satellite mission in communications, sensing or nav-igation. The primary enabler is that almost all satellite applications involve the collection and dissemination of information and can thus be treated as modular information process-ing networks. This generalization allows the adoption of the mathematics for information network ow, leading to a logical classi cation scheme for satellite systems. The bene ts and issues that are characteristic of each system class are identi ed, in terms of their capa-bility, performance and cost. The quantitative analysis methodology speci es measurable, unambiguous metrics for the cost, capability, performance and adaptability. The Capabili-ties are characterized by four quality of service parameters that relate to the isolation, rate, integrity and availability of the information transferred between origin-destination pairs within a market. Performance is the probability of satisfying the user's requirements for these parameters. The Cost per Function metric is the average cost incurred to provide satisfactory service to a single user, and Adapatability metrics are sensitivity indicators. Validation of the methodology is provided by a comprehensive quantitative analysis of the

Graeme B. Shaw
1998-01-01

425

Estimating lightning current moment waveforms from satellite optical measurements

  Physics Websites

Summary: Estimating lightning current moment waveforms from satellite optical measurements Toru Adachi,1 and Duke magnetometer observed clear optical and radio signatures of 12 sprite- producing lightning events to remotely measure lightning current moment, which is critical for understanding the production of sprites

California at Berkeley, University of

426

A spectral comparison of (379) Huenna and its satellite

  MIT - DSpace

Summary: We present near-infrared spectral measurements of Themis family Asteroid (379) Huenna (D ? 98 km) and its 6 km satellite using SpeX on the NASA IRTF. The companion was farther than 1.5? from the primary at the time of ...

DeMeo, Francesca E.

427

The Luminosity Function of the Milky Way Satellites

  CERN Preprints

Summary: We quantify the algorithmic detectability of stellar Milky Way satellites in data release 5 (DR5) of the Sloan Digital Sky Survey (SDSS), and use this to estimate the luminosity function of faint satellite galaxies in our halo. We develop a satellite detection algorithm based on the convolution of the DR5 star catalog with a kernel of zero net flux that is the difference of a narrow positive Gaussian and a much wider negative Gaussian, which removes the background star-count level. This permits us to assess the significance of any (positive) detection in terms of deviations of this map. The efficiency of this algorithm is tested by computing the recovery rate of a large set of mock objects added to SDSS DR5 as a function of their luminosity, size and distance from the Sun. Most of the recent Milky Way satellite discoveries, made by SDSS, are shown to lie very close to the survey's detection limits. Calculating the maximum accessible volume $V_{max}$ for all faint detected objects makes it possible for the fir...

Koposov, S; Evans, N W; Hewett, P C; Irwin, M J; Gilmore, G; Zucker, D B; Rix, H -W; Fellhauer, M; Bell, E F; Glushkova, E V
2007-01-01

428

Image deblurring, Spectrum Interpolation and Application to Satellite Imaging

  Mathematics Websites

Summary: Image deblurring, Spectrum Interpolation and Application to Satellite Imaging Sylvain Durand complementary methods in noisy image deblurring: a nonlinear shrinkage of wavelet­packets coefficients called FCNR and Rudin­Osher­Fatemi's variational method. The FCNR has for objective to obtain a restored image

Malgouyres, François

429

Estimation of ICAO Threat Model Parameters For Operational GPS Satellites

  Engineering Websites

Summary: Estimation of ICAO Threat Model Parameters For Operational GPS Satellites Alexander M. Mitelman Laboratory, his research is focused on local area differential GPS design, signal analysis, and applications availability, and continuity. ABSTRACT The ICAO Second Order Step threat model defines a class of signal

Stanford University

430

Cyclone Global Navigation Satellite System (CYGNSS) Mission Overview

  Engineering Websites

Summary: -resolutionwindfieldimageryofTCgenesis,intensificationanddecay. GPS satellites CYGNSS Observatories Primary Objectives: · Measure ocean surface wind speed in all precipitating conditions, including those experienced in the TC eyewall · Measure ocean surface wind speed wind speed data products, and helping them assess the value of these products for use

Eustice, Ryan

431

Small Satellite Missions Designed, Built, Tested, and Operated by LASP

  Geosciences Websites

Summary: Small Satellite Missions Designed, Built, Tested, and Operated by LASP LASP designs and operates's Student Explorer Demonstration Initiative program (STEDI). The SNOE team designed and built two, launched in 2012, is part of NSF's Geoscience CubeSat program. The CSSWE team designed and built

Mojzsis, Stephen J.

432

NO2 from satellites, ground-based measurements, and CMAQ

  Geosciences Websites

Summary: (Wisconsin Horizontal Interpolation Program for Satellites) ­ now with MODIS AOD 2 #12;In situ AQS NO2 OMI NO2 column Model How can air quality managers use these three data sets? #12;In situ AQS NO2 OMI NO2 column Model How well does the model capture obs? #12;In situ AQS NO2 OMI NO2 column Model How well does

Jacob, Daniel J.

433

SATELLITE ATTITUDE TRACKING BY QUATERNION-BASED BACKSTEPPING

  Engineering Websites

Summary: by application of the LaSalle-Yoshizawa theorem. This is a part of a study of possible control methods reaction control thrusters and one reaction wheel, and simulation results based on data from the satellite a project named Student Space Exploration & Tech- nology Initiative (SSETI), a project where students from

Gravdahl, Jan Tommy

434

A Lagrangian Heuristic for Satellite Range Scheduling with ...

  Optimization Online

Summary: Finally, the ground station can process at most one task at a time and tasks ... standard crossover mechanisms for deriving feasible good schedules within subgra- ... ej > dj, in which the on-board operation associated to j must be started. ...... Maintenance operations include special satellite tests (TEST), on-board software.


2006-05-24

435

SATELLITE BASED SHORT-TERM FORECASTING OF SOLAR IRRADANCE

  Power Transmission, Distribution and Plants Websites

Summary: . Examples are the storage management in stand-alone photovoltaic or wind energy systems, control of solarSATELLITE BASED SHORT-TERM FORECASTING OF SOLAR IRRADANCE - COMPARISON OF METHODS AND ERROR Forecasting of solar irradiance will become a major issue in the future integration of solar energy resources

Heinemann, Detlev

436

SPICE Testbed: A DTN Testbed for Satellite and Space Communications

  Engineering Websites

Summary: SPICE Testbed: A DTN Testbed for Satellite and Space Communications Ioannis Komnios, Ioannis Protocol and its architecture has been designed to support multiple DTN implementations and a variety mechanisms in a variety of space communication scenarios. Keywords: Delay Tolerant Networking, DTN Testbed

Tsaoussidis, Vassilis

437

SLOT ALLOCATION IN A TDMA SATELLITE SYSTEM: SIMULATED

  Engineering Websites

Summary: - signment problem in a multi-spot geostationary satellite. Radio interference impose constraints experimentations are provided to test our proposed improvements. 1 Introduction We consider a multi-spot section. 2 Problem Description Our design of a multi-spot TDMA system con- sists of two phases


438

Cognitive Vision for Autonomous Satellite Rendezvous and Docking

  Computer Technologies and Information Sciences Websites

Summary: with the challenge of effec- tively combining low-level vision with artificial intelli- gence. Some of the earliestCognitive Vision for Autonomous Satellite Rendezvous and Docking Faisal Z. Qureshi and Demetri MDRobotics Limited, Brampton, ON L6S 4J3, Canada Abstract We present a cognitively-controlled vision system

Toronto, University of

439

Tectonics of the outer planet satellites Geoffrey C. Collins

  Geosciences Websites

Summary: planets range from the familiar, such as clearly recognizable graben on many satellites, to the bizarre are dominated by water ice near their surfaces. Though ice is a brittle material at the cold temperatures found may be the result of changes in their tidal figures, or motions of their solid surfaces with respect

Nimmo, Francis

440

Astronomy 241: Foundations of Astrophysics I 15. Satellites of Giants

  Physics Websites

Summary: Moons · spherical due to self-gravity · composed of ices & rock · most* formed in disks around parent: solid #12;Activity: Galilean Satellites Wide range of geological activity: -- Io is most volcanic object. #12;Europa: an Ice-Covered Ocean? Exaggerated colors "Natural" colors Pwyll: Impact crater Fractures

Barnes, Joshua Edward

441

Adaptive Thermal Modeling Architecture for Small Satellite Applications

  Engineering Websites

Summary: the mission. The varying thermal environment in space is particularly important to spacecraft designAdaptive Thermal Modeling Architecture for Small Satellite Applications 2Lt. John Anger Richmond, USAF Colonel John Keesee, USAF Retired May 2010 SSL # 4-10 #12;#12;Adaptive Thermal Modeling


442

The Mass Dependence of Dwarf Satellite Galaxy Quenching

  CERN Preprints

Summary: We combine observations of the Local Group with data from the NASA-Sloan Atlas to show the variation in the quenched fraction of satellite galaxies from low mass dwarf spheroidals and dwarf irregulars to more massive dwarfs similar to the Magellanic clouds. While almost all of the low mass ($M_\\star \\lesssim 10^7$ $M_\\odot$) dwarfs are quenched, at higher masses the quenched fraction decreases to approximately 40-50%. This change in the quenched fraction is large, and suggests a sudden change in the effectiveness of quenching that correlates with satellite mass. We combine this observation with models of satellite infall and ram pressure stripping to show that the low mass satellites must quench within 1-2 Gyr of pericenter passage to maintain a high quenched fraction, but that many more massive dwarfs must continue to form stars today even though they likely fell in to their host >5 Gyr ago. We also characterize how the susceptibility of dwarfs to ram pressure must vary as a function of mass if it is to acco...

Slater, Colin T
2014-01-01

443

Variability in Satellite SST Data Edward M. Armstrong

  Environmental Sciences and Ecology Websites

Summary: ;Comparison methodology Globally regrid daily satellite SST data to 1 degree resolution on monthly time scales. For the entire time series, compute standard statistics for differences on monthly scales for mean bias, RMS;Monthly anomaly time series Time series of monthly MPSST, ONSST, and OISST minus WOA98 climatological SST


444

Improvements in DCCP congestion control for satellite links

  Physics Websites

Summary: ) intended for use with real-time traffic, which are aimed at improving its performance for long delay of multimedia and real time traffic and the primary purpose of introducing DCCP was to better handle real measurements on a live satellite link by implementing our proposal inside the Linux kernel DCCP

Paris-Sud XI, Université de

445

Telescope Management for Satellite Tracking: A Decentralized Approach

  Computer Technologies and Information Sciences Websites

Summary: 100 million pieces of space junk exist in Low-Earth Orbit (LEO) with over 21,000 objects being larger) monitors the trajectories of large orbiting objects using 29 sites located around the world. Due and the fidelity of tracks. Many of LEO satellites are bright enough to be seen by the naked eye as they streak

Mailler, Roger

446

Cassini Imaging of Jupiter's Atmosphere, Satellites, and Rings

  Physics Websites

Summary: Cassini Imaging of Jupiter's Atmosphere, Satellites, and Rings Carolyn C. Porco,1 * Robert A. West Science Subsystem acquired about 26,000 images of the Jupiter system as the spacecraft encountered the giant planet en route to Saturn. We report findings on Jupiter's zonal winds, convective storms, low


447

Dust en-route to Jupiter and the Galilean satellites

  Astrophysics (arXiv)

Summary: Spacecraft investigations during the last ten years have vastly improved our knowledge about dust in the Jovian system. All Galilean satellites, and probably all smaller satellites as well, are sources of dust in the Jovian system. In-situ measurements with the dust detectors on board the Ulysses and Galileo spacecraft have for the first time demonstrated the electromagnetic interaction of charged dust grains with the interplanetary magnetic field and with a planetary magnetosphere. Jupiter's magnetosphere acts as a giant mass-velocity spectrometer for charged 10-nanometer dust grains. These dust grains are released from Jupiter's moon Io with typical rate of 1 kg s^1. The dust streams probe the plasma conditions in the Io plasma torus and can be used as a potential monitor of Io's volcanic plume activity. The other Galilean satellites are surrounded by tenuous impact-generated clouds of mostly sub-micrometer ejecta grains. Galileo measurements have demonstrated that impact-ejecta derived from hypervelocity impacts onto satellites are the major -- if not the only -- constituent of dusty planetary rings. We review the in-situ dust measurements at Jupiter and give an update of most recent results.

Harald Krueger; Eberhard Gruen
2002-05-28

448

GALILEAN SATELLITES ASTR/GEOL 5800 Planetary Surfaces & Interiors

  Geosciences Websites

Summary: · En route, it observed the SL9 comet impact into Jupiter · Arrived at Jupiter in 1995 and deployed probe into Jupiter's atmosphere · Very complex series of fly-bys of all major Galilean satellites · Deliberately crashed into Jupiter Sept 2003 (why?) · Main source of results antenna #12;Where are they? 5 10 15

Mojzsis, Stephen J.

449

Validation of satellite ozone profile retrievals using Beijing ozonesonde data

  Geosciences Websites

Summary: adversely impact human health and plant growth. Since ozone in both the stratosphere and the troposphere, the Atmospheric Infrared Sounder (AIRS) on the NASA Aqua satellite and the Microwave Limb Sounder (MLS coincident ozone profiles from AIRS version 4 retrieval and MLS version 1.5 retrieval. Qualitatively, both

Pan, Laura

450

The Physics and Chemistry of Terrestrial Planetary and Satellite Accretion

  University of California eScholarship Repository

Summary: planet accretion – And interpretation of the Hf-W chronometer. Earth and Planetary Scienceplanets from a large number of N-body simulations. Earth and Planetary SciencePLANET AND SATELLITE ACCRETION A dissertation submitted in partial satisfaction of the requirements for the degree of DOCTOR OF PHILOSOPHY in EARTH SCIENCES

Wasem, Christina
2014-01-01

451

Studying the Ocean CIOSSCooperative Institute for Oceanographic Satellite Studies

  Geosciences Websites

Summary: and validation plan, for color products for the coastal and open ocean. Science workshop topics include oceanStudying the Ocean from Space CIOSSCooperative Institute for Oceanographic Satellite Studies #12 understanding of, and operational products related to, the upper ocean and air-sea interface by using data from

Kurapov, Alexander

452

Lattice Formation in Space for a Swarm of Pico Satellites

  Computer Technologies and Information Sciences Websites

Summary: a lattice in orbit around a planet. The system, based on the artificial potential field approach, proposes that allows a swarm of small space- craft, called pico satellites, to build an hexagonal lattice in orbit). In this paper, we optimize the control pa- rameters for a real orbital environment and we study the precision

Vinko, Tamas

453

Orbit Maneuvers Through Inter-Satellite Forcing Michael C. Norman

  Engineering Websites

Summary: Orbit Maneuvers Through Inter-Satellite Forcing Michael C. Norman and Mason A. Peck Cornell-contacting spacecraft for orbit change and maintenance maneuvers. These types of forces are internal to the overall system, allowing them to modify the angular momentum of the individual spacecraft while conserving

Peck, Mason A.

454

ANGULAR RATE ESTIMATION FOR GYROLESS SATELLITE ATTITUDE CONTROL

  Engineering Websites

Summary: ANGULAR RATE ESTIMATION FOR GYROLESS SATELLITE ATTITUDE CONTROL Brij N. Agrawal1 and William J a real time angular rate calculation from the system dynamic model and a Kalman filter estimator of estimating multi-body spacecraft angular rates. This method is ideally suited to a spacecraft designed


455

yclone Tracking using Multiple Satellite Image Sources Anand Panangadan

  Biology and Medicine Websites

Summary: yclone Tracking using Multiple Satellite Image Sources Anand Panangadan Jet Propulsion Laboratory.V.Panangadanshen.shyang.hoAshit.Talukder}@jpl.nasa.gov Shen-Shyang Ho Jet Propulsion Laboratory California Institute of Technology Pasadena CA 91109 Ashit Talukder Jet Propulsion Laboratory California Institute of Technology Pasadena CA 91109 ABSTRACT We present

Panangadan, Anand

456

Performance Study of Routing Algorithms for LEO Satellite Constellations

  Computer Technologies and Information Sciences Websites

Summary: 1 Performance Study of Routing Algorithms for LEO Satellite Constellations Ioannis Gragopoulos A comparative study of routing techniques is carried out on complicated LEO constellations interconnecting high a comparative study of Shortest Paths (SP) and optimal routing #12;2 algorithms for complicated LEO

Papapetrou, Evaggelos

457

Distributed Load-Aware Routing in LEO Satellite Evangelos Papapetrou

  Computer Technologies and Information Sciences Websites

Summary: Distributed Load-Aware Routing in LEO Satellite Networks Evangelos Papapetrou University on account of their inherent broadcasting nature and large scale coverage. In the past, Low Earth Orbit (LEO, the success of LEO systems in the past decade was limited as a result of their failure to compete

Papapetrou, Evaggelos

458

Dust en-route to Jupiter and the Galilean satellites

  CiteSeer

Summary: Spacecraft investigations during the last ten years have vastly improved our knowledge about dust in the Jovian system. All Galilean satellites, and probably all smaller satellites as well, are sources of dust in the Jovian system. In-situ measurements with the dust detectors on board the Ulysses and Galileo spacecraft have for the first time demonstrated the electromagnetic interaction of charged dust grains with the interplanetary magnetic field and with a planetary magnetosphere. Jupiter’s magnetosphere acts as a giant mass-velocity spectrometer for charged 10-nanometer dust grains. These dust grains are released from Jupiter’s moon Io with typical rate of ? 1kg s ?1. The dust streams probe the plasma conditions in the Io plasma torus and can be used as a potential monitor of Io’s volcanic plume activity. The other Galilean satellites are surrounded by tenuous impact-generated clouds of mostly sub-micrometer ejecta grains. Galileo measurements have demonstrated that impact-ejecta derived from hypervelocity impacts onto satellites are the major – if not the only – constituent of dusty planetary rings. We review the in-situ dust measurements at Jupiter and give an update of most recent results.

Harald Krüger; Eberhard Grün
2002-01-01

459

Anisotropy in the Distribution of Satellite Galaxy Orbits

  Astrophysics (arXiv)

Summary: Nearby clusters such as Virgo and Coma possess galaxy distributions which tend to be aligned with the principal axis of the cluster itself. This has also been confirmed by a recent statistical analysis of some 300 Abell clusters where the effect has been linked to the dynamical state of the cluster. Moreover, the orbits of satellite galaxies in galactic systems like our own Milky Way also demonstrate a high degree of anisotropy - the so-called Holmberg effect, the origin of which has been the subject of debate for more than 30 years. This study presents the analysis of cosmological simulations focusing on the orbits of satellite galaxies within dark matter halos. The apocentres of the orbits of these satellites are preferentially found within a cone of opening angle ~40 around the major axis of the host halo, in accordance with the observed anisotropy found in galaxy clusters. We do, however, note that a link to the dynamical age of the cluster is not well established as both our oldest dark matter halos do show a clear anisotropy signal. Further analysis connects this distribution to the infall pattern of satellites along the filaments: the orbits are determined rather by the environment of the host halo than some "dynamical selection" during their life within the host's virial radius.

Alexander Knebe; Stuart P. D. Gill; Brad K. Gibson; Geraint F. Lewis; Rodrigo A. Ibata; Michael A. Dopita
2003-11-10

460

15 Minutes about satellite aerosol products (from VIIRS)

  Environmental Sciences and Ecology Websites

Summary: GEOSCHEM to model the vertical distribution of aerosol and estimat15 Minutes about satellite aerosol products (from VIIRS) Edward J. Hyer Naval Research Laboratory #12;In this talk · Basics of aerosol measurement from space · Some results presented at a recent NOAA

Jacob, Daniel J.

461

Statistics of Satellite Galaxies Around Milky Way-Like Hosts

  CERN Preprints

Summary: We calculate the probability that a Milky-Way-like halo in the standard cosmological model has the observed number of Magellanic Clouds (MCs). The statistics of the number of MCs in the LCDM model are in good agreement with observations of a large sample of SDSS galaxies. Under the sub-halo abundance matching assumption of a relationship with small scatter between galaxy r-band luminosities and halo internal velocities, vmax, we make detailed comparisons to similar measurements using SDSS DR7 data by Liu et al 2010. Models and observational data give very similar probabilities for having zero, one, and two MC-like satellites. In both cases, Milky Way-luminosity hosts have just a ~10% chance of hosting two satellites similar to the Magellanic Clouds. In addition, we present a prediction for the probability for a host galaxy to have N satellite galaxies as a function of the magnitudes of both the host and satellite. This probability and its scaling with host properties is significantly different from that of ma...

Busha, Michael T; Behroozi, Peter S; Gerke, Brian F; Klypin, Anagoly A; Primack, Joel R
2010-01-01

462

1. INTRODUCTION Satellite Doppler navigation, developed between 1957

  Engineering Websites

Summary: -Aviv University Analytical analysis of the system perfoimance is hampered by the nonlinear nature of the problem that minimizes the Analytic expressions of the random errors in a satellite Doppler difference between of the geometry been based on numerical simulation. (range and angle), pass-length, and signal-to-noise ratio (SNR

Levanon, Nadav

463

Radiative Transfer, Satellite Retrieval Systems and 32 Years

  Environmental Sciences and Ecology Websites

Summary: · Six channels (747, 725, 708, 695, 676, 668.5 cm-1) in the 15-micrometer CO2 absorption band, and eight vapor absorption band. #12;Satellite Processing and Display System · Worked on ingesting GOES Mode AA data · VAS sounding and multispectral imaging · Developed Smith Iterative Sounding System #12

Kuligowski, Bob

464

Design, Implementation and Control of a Sparse Aperture Imaging Satellite

  Engineering Websites

Summary: was undertaken. The MIT Adaptive Reconnaissance Golay- 3 Optical Satellite (ARGOS) project exploits wide. To demonstrate a complete spacecraft in a 1-g environment, the ARGOS system is mounted on a frictionless air and imple- mentation phases of ARGOS. A preliminary assessment shows that the beam combining problem


465

Satellite Survival in Highly Resolved Milky Way Class Halos

  CERN Preprints

Summary: Surprisingly little is known about the origin and evolution of the Milky Way's satellite galaxy companions. UV photoionisation, supernova feedback and interactions with the larger host halo are all thought to play a role in shaping the population of satellites that we observe today, but there is still no consensus as to which of these effects, if any, dominates. In this paper, we revisit the issue by re-simulating a Milky Way class dark matter (DM) halo with unprecedented resolution. Our set of cosmological hydrodynamic Adaptive Mesh Refinement (AMR) simulations, called the Nut suite, allows us to investigate the effect of supernova feedback and UV photoionisation at high redshift with sub-parsec resolution. We subsequently follow the effect of interactions with the Milky Way-like halo using a lower spatial resolution (50pc) version of the simulation down to z=0. This latter produces a population of simulated satellites that we compare to the observed satellites of the Milky Way and M31. We find that supernov...

Geen, Sam; Devriendt, Julien
2012-01-01

466

Long-Distance Quantum Communication with Entangled Photons using Satellites

  CERN Preprints

Summary: The use of satellites to distribute entangled photon pairs (and single photons) provides a unique solution for long-distance quantum communication networks. This overcomes the principle limitations of Earth-bound technology, i.e. the narrow range of some 100 km provided by optical fiber and terrestrial free-space links.

Aspelmeyer, M; Pfennigbauer, M; Leeb, W; Zeilinger, Anton; Aspelmeyer, Markus; Jennewein, Thomas; Pfennigbauer, Martin; Leeb, Walter; Zeilinger, Anton
2003-01-01

467

Contention Resolution and Channel Estimation in Satellite Random Access Channels

  Engineering Websites

Summary: Contention Resolution and Channel Estimation in Satellite Random Access Channels Lei Xiao EURECOM Mobile Communications Department BP193, F-06560 Sophia Antipolis, France Email: lei.xiao@eurecom.fr Laura Cottatellucci EURECOM Mobile Communications Department BP193, F-06560 Sophia Antipolis, France Email: laura

Gesbert, David

468

Tropospheric emission spectrometer for the Earth Observing System's Aura satellite

  Environmental Sciences and Ecology Websites

Summary: -dimensional measure- ments of tropospheric ozone and of the physical­chemical factors that control its formation arrays. In addition, the measurements require an instrument that can operate in both nadir and limbRDLS and the Ozone Measuring Instrument OMI . The Aura satellite Fig. 1 will be launched in June 2003 into a Sun


469

Satellite Accretion Onto Massive Galaxies With Central Black Holes

  CERN Preprints

Summary: Minor mergers of galaxies are expected to be common in a hierarchical cosmology such as $\\Lambda$CDM and have the potential to significantly affect galactic structure. In this paper we dissect the case-by-case outcome from a set of numerical simulations of a single satellite elliptical galaxy accreting onto a massive elliptical galaxy. We take care to explore cosmologically relevant orbital parameters and to set up realistic initial galaxy models that include all three relevant dynamical components: dark matter halos, stellar bulges, and central massive black holes. The effects of several different parameters are considered, including orbital energy and angular momentum, satellite density and inner density profile, satellite-to-host mass ratio, and presence of a black hole at the center of the host. Black holes play a crucial role in protecting the shallow stellar cores of the hosts, as satellites merging onto a host with a central black hole are more strongly disrupted than those merging onto hosts without b...

Boylan-Kolchin, M; Boylan-Kolchin, Michael; Ma, Chung-Pei
2006-01-01

470

The study of cirrus clouds using airborne and satellite data

  Texas A&M University - TxSpace

Summary: been detected by satellite measurements [36], ground-based lidar [27], and space shuttle- borne lidars [45]. Total cirrus cover has been found to be over 50% for the entire tropics [5], and a thin cirrus layer may be present as much as 80% of the time...

Meyer, Kerry Glynne
2004-09-30

471

IP ROUTING ISSUES IN SATELLITE CONSTELLATION NETWORKS A. CLERGET,2

  Engineering Websites

Summary: at the various networking layers as described by the ISO OSI Reference Model.1 Networking using satellites began; in conjunction with its terrestrial gateway stations it forms an autonomous system (AS). Over the same period for computer network communication in the world. In this paper, we examine how IP routing can be implemented

Wood, Lloyd

472

Recent La Plata basin drought conditions observed by satellite gravimetry

  Geosciences Websites

Summary: and Climate Experiment (GRACE) provides quantitative measures of terrestrial water storage (TWS) change. GRACE changes derived from Terra satellite observations. The Global Land Data Assimilation System model captures in the world and second largest in South America, next to the Amazon basin. With a total area of about 3

Yang, Zong-Liang

473

TCP SPLITTING PROTOCOL FOR BROADBAND AERONAUTICAL SATELLITE NETWORK

  Engineering Websites

Summary: -Elliott channel model for satellite channel since protocol behavior often depends strongly on the channel behavior in the world. However, modernization is required for several reasons. First, the move toward Free Flight segment for interconnection of the cabin with the terrestrial networks, ground segment which provides

Baras, John S.

474

Reducing Retransmissions in Point-to-point Satellite Transmissions

  Physics Websites

Summary: Reducing Retransmissions in Point-to-point Satellite Transmissions J´er^ome Lacan and Tanguy P that reduces the number of retransmissions needed to ensure reliable unicast transmissions over a shared the end-to-end jitter and delay. After each block transmission, the mechanism determines the minimal set

Paris-Sud XI, Université de

475

RESEARCH ARTICLE Satellite-indicated long-term vegetation changes

  Geosciences Websites

Summary: production. This study aimed to explore long-term changes in vegetation greenness and land surface phenology;vegetation dynamics can contribute to grassland biomass estimations, grazing capacity predictions publications using satellite data have recog- nized a more neutral situation, involving both declines

Hutyra, Lucy R.

476

How PEDOT:PSS solutions produce satellite-free inkjets

  University of Cambridge - Dspace

Summary: and in the fabrication of conductive features can even cause bridging between neighbouring tracks, device failure and low production yield. Air, moisture and dust carried by satellite drops onto the substrate, film and/or main drop may also degrade the final film...

Hoath, S.D.; Jung, S.-J.; Hsiao, W.-K.; Hutchings, I.M.
2012-01-01

477

Molecular biology study of satellite panicum mosaic virus capsid protein

  Texas A&M University - TxSpace

Summary: Satellite panicum mosaic virus (SPMV) depends on its helper Panicum mosaic virus (PMV) for replication and movement in host plants. The positive-sense single-stranded genomic RNA of SPMV encodes a 17-kDa capsid protein (CP) to form 16-nm virions...

Qi, Dong
2009-05-15

478

International Satellite Cloud Climatology Project (ISCCP) Radiance Calibration Report

  CiteSeer

Summary: -launch calibration supplied by the satellite operator for the visible (VIS) channel (and other channels at solar wavelengths) and an equation or table used to interpret on-board calibration information for the infrared (IR) channel (and other channels at thermal infrared wavelengths). Specific details are given for

William Rossow; Yves Desormeaux; Christopher L. Brest; Alison Walker
1992-01-01

479

Annual AIAA/USU Conference on Small Satellites

  Computer Technologies and Information Sciences Websites

Summary: energy have limitations because of the size of their solar panels. With the limitations on the solar 9670 s.jain1@csuohio.edu, d.j.simon@csuohio.edu ABSTRACT: Small spacecraft that are powered by solar panel size, it is generally hard to comply with the demands from all the satellite subsystems, payloads

Simon, Dan

480

FORMATION FLYING SATELLITE CONTROL UTILIZING INPUT SHAPING Erika Biediger

  Engineering Websites

Summary: Singhose The precise control of spacecraft with flexible appendages, such as solar panels or antennas Architectures The precise control of spacecraft with flexible appendages, such as solar panels or antennas recognizable being solar panels and communications antennae. Many flexible satellites are positioned

Singhose, William

481

Hybrid 3D Modeling of Large Landscapes from Satellite Maps

  Computer Technologies and Information Sciences Websites

Summary: Hybrid 3D Modeling of Large Landscapes from Satellite Maps Project in Lieu of Thesis for Master resolution 3D terrain data over an intra and internet. Due to advanced software technology and innovative with the information to display excellent high quality representations of complex terrains and landscapes

Abidi, Mongi A.

482

Using 8-color Multispectral Satellite for Observation of Wave Motion

  Computer Technologies and Information Sciences Websites

Summary: relation for surface gravity waves was used to de- termine nearshore ocean depthUsing 8-color Multispectral Satellite for Observation of Wave Motion COASTAL BATHYMETRY For Further Postgraduate School RRSSCC Coastal bathymetry near Camp Pendleton, California was mea- sured using wave motion


483

A Satellite Survey of Cloud Cover and Water Vapour

  Physics Websites

Summary: A Satellite Survey of Cloud Cover and Water Vapour in Morocco and Southern Spain and a Verification on atmospheric cloud cover and water vapour, it has been recognized that a quantitative survey and water vapour at telescope sites but basically there are two categories: ground-based observations


484

Testing modified gravity with motion of satellites around galaxies

  General Relativity & Quantum Cosmology (arXiv)

Summary: A modified gravity (MOG) theory, that has been successfully fitted to galaxy rotational velocity data, cluster data, the Bullet Cluster 1E0657-56 and cosmological observations, is shown to be in good agreement with the motion of satellite galaxies around host galaxies at distances 50-400 kpc.

J. W. Moffat; V. T. Toth
2008-08-10

485

An Improved In Situ and Satellite SST Analysis

  Environmental Sciences and Ecology Websites

Summary: OI.v2 #12;Seasonal Differences #12;Objective Determination of Analysis Accuracy · Withhold a randomAn Improved In Situ and Satellite SST Analysis Richard W. Reynolds Thomas Smith NCDC Plan ­ Skin vs. Bulk Problem #12;SST Anomaly Data and Analysis #12;Data Coverage #12;Ship Minus Buoy


486

Indexing of satellite images with different resolutions by wavelet features

  Physics Websites

Summary: . I. INTRODUCTION Spatial agencies are very rapidly building up massive databases of images are rapidly building up massive image databases. A particularity of these databases is that they are made. For example, the CNES (the French spatial agency) is receiving from its satellites several terabytes of data

Paris-Sud XI, Université de

487

The Physics and Chemistry of Terrestrial Planetary and Satellite Accretion

  University of California eScholarship Repository

Summary: McKinnon, W.B. (Eds. ), Jupiter. The Planet, Satellites andJupiter and Saturn are in their current orbit during terrestrial planetJupiter migrated extensively during the formation of the solar system, with potentially dramatic effects on the terrestrial planet

Wasem, Christina
2014-01-01

488

Wednesday, March 15, 2006 SATURN'S COMPANIONS: SATELLITES AND RINGS

  Physics Websites

Summary: . Turtle E. Denk T. Neukum G. Roatsch T. Wagner R. Giese B. Squyres S. Burns J. McEwen A. Porco C. Johnson. Lunine J. I. Davies A. G. McCord T. B. Thomas P. C. Turtle E. P. Enceladus' Interior and Geysers. Helfenstein P. Porco C. Burns J. Denk T. Turtle E. Jacobson R. A. Shapes of the Saturnian Icy Satellites

Rathbun, Julie A.

489

The Geostationary Operational Environment Satellite R-Series Program

  Geosciences Websites

Summary: flares that can dis- rupt communications and degrade navigational accuracy. EUVS monitors solar variations that directly affect satellite drag/tracking and ionospheric changes, which impact communication and navigation operations. EXIS will provide one of the most important observations for early warning of space

Mojzsis, Stephen J.

490

Detection of Urban Zones in Satellite Images Using Visual Words

  Computer Technologies and Information Sciences Websites

Summary: 1 Detection of Urban Zones in Satellite Images Using Visual Words Lior Weizman and Jacob Goldberger classification. An important usage of remotely sensed data is extracting urban regions to update GIS databases methods for urban extraction that exist today are sensitive to atmospheric and radiometric parameters

Goldberger, Jacob

491

Observing geomagnetic induction in magnetic satellite measurements and associated

  Fossil Fuels Websites

Summary: Observing geomagnetic induction in magnetic satellite measurements and associated implications@ucsd.edu; cconstable@ucsd.edu) [1] Currents induced in Earth by temporal variations in the external magnetic field have magnetic measurements: this is done by removing the magnetic contributions of the main (core) magnetic

Constable, Steve

492

Global assessment of ocean carbon export by combining satellite observations

  Geosciences Websites

Summary: Global assessment of ocean carbon export by combining satellite observations and food-web models D, to drive a food-web model that estimates the production of sinking zooplankton feces and algal aggregates the surface ocean by sinking particles is an important, yet highly uncertain, component of the global carbon

Buesseler, Ken

493

Human Muscle Satellite Cells as Targets of Chikungunya Virus Infection

  Physics Websites

Summary: Huerre2 , Jean-Pierre Riviere3 , Lark L. Coffey4 , Philippe V. Afonso1 , Vincent Mouly5 , Jean de, Afonso PV, et al (2007) Human Muscle Satellite Cells as Targets of Chikungunya Virus Infection. PLoS ONE 2(6): e527. doi:10.1371/journal.pone.0000527 INTRODUCTION Chikungunya virus (CHIKV) is a moquito

Paris-Sud XI, Université de

494

Satellite Ultrasound for Rural Stroke (SURS) Principal investigator: Dr Alasdair Mort, University of Aberdeen

  Mathematics Websites

Summary: Satellite Ultrasound for Rural Stroke (SURS) Principal investigator: Dr Alasdair Mort, University then sends these data via satellite to a remote location for review. We shall also carry out a pilot study

Levi, Ran

495

Resource allocation and scheduling for communication satellites with advanced transmission antennas

  MIT - DSpace

Summary: For multimedia and other data services over satellite networks, the efficient management of scarce satellite communication resources is critical for the economic competitiveness of the medium. To support a broad spectrum ...

Choi, Jihwan Patrick, 1975-
2006-01-01

496

The co-planarity of satellite galaxies delivered by randomly aligned cold mode accretion streams

  CERN Preprints

Summary: Recent observations have shown that the majority of the Andromeda galaxy's satellites are aligned in a thin plane. On the theoretical side it has been proposed that galaxies acquire their gas via cold streams. In addition, numerical simulations show that the same streams also deliver satellites. Assuming that cold streams are the major source of satellite systems around galaxies we calculate the probabilities to find a certain fraction of satellites within a thin plane around the central galaxy of the host halo. Using simple geometrical considerations and adopting a random orientation of the streams we demonstrate that the vast thin disk of satellites detected around Andromeda can naturally be explained within this framework. In fact, without any satellite scattering, three streams or less would lead to too many satellites in the thin plane, compared with the observations. Four to seven streams reproduce the observations very well. Thin disks of satellites might therefore provide important relic information a...

Goerdt, Tobias
2013-01-01

497

COASTAL CURRENTS MONITORING USING RADAR SATELLITES BASED ON WAVE TRACKING APPROACH

  Geosciences Websites

Summary: structures, beach erosion, natural hazards, and environmental problems are the issues related to hydrodynamic pulse to travel from the satellite antenna to the surface and back to the satellite receiver. Moreover

Stuttgart, Universität

498

Interpreting the Morphology of Diffuse Light Around Satellite Galaxies

  Astrophysics (arXiv)

Summary: Recent observations of surface brightness distributions of both Milky Way and M31 satellite galaxies have revealed many instances of sudden changes or breaks in the slope of the surface brightness profiles (at some break radius, r_break). These breaks are often accompanied by increasingly elliptical isophotes and sometimes by isophote twisting. We investigate the hypothesis of a tidal origin for these features by applying the same ellipse fitting techniques that are used on observed galaxies to numerical simulations of the destruction of satellites, represented by spherical, single-component systems. We examine how observed quantities such as r_break, ellipticity and position angle of the fitted ellipses and amplitude of extra-break population vary with the satellite's orbital eccentricity and phase, and our viewpoint relative to the orbit. We also look at orbit and viewpoint dependence of the rate of change of the latter three quantities with radius. We find that there are trends with orbital phase and eccentricity in all observed quantities, many of which are preserved through a wide variety of viewing angles. In particular, a generic feature of all simulations is a depletion zone just interior to an excess zone, regions in which the surface brightness is lower and higher, respectively, than the initial profile. A clear interpretation of any individual image, however, is likely to be hampered by the dependence of the observable features on these multiple parameters. For example, breaks can be excited by several physical processes and can occur well within the bound satellite population. Nevertheless, we do find we can place loose constraints on the tidal radius, mass loss rate, orbital type and phase of the satellite, and nature of breaks using photometric data alone.

Kathryn V. Johnston; Philip I. Choi; Puragra Guhathakurta
2002-04-15

499

Interpreting Debris from Satellite Disruption In External Galaxies

  Astrophysics (arXiv)

Summary: We examine the detectability and interpretation of debris trails caused by satellite disruption in external galaxies using semi-analytic approximations for the dependence of streamer length, width and surface brightness on satellite and primary galaxy characteristics. The semi-analytic method is tested successfully against N-body simulations and then applied to three representative astronomical applications. First, we show how streamer properties can be used to estimate mass-to-light ratios $\\Upsilon$ and streamer ages of totally disrupted satellites, and apply the method to the stellar arc in NGC 5907. Second, we discuss how the lack of observed tidal debris around a satellite can provide an upper limit on its mass-loss rate, and, as an example, derive the implied limits on mass-loss rates for M32 and NGC 205 around Andromeda. Finally, we point out that a statistical analysis of streamer properties might be applied to test and refine cosmological models of hierarchical galaxy formation, and use the predicted debris from a standard $\\Lambda$CDM realization to test the feasibility of such a study. Using the Local Group satellites and the few known examples of debris trails in the Galaxy and in external systems, we estimate that the best current techniques could characterize the brightest ($R < 29$ mag/ arcsec$^{2}$) portions of the youngest (3 dynamical periods) debris streamers. If systematics can be controlled, planned large-aperture telescopes such as CELT and OWL may allow fainter trails to be detected routinely and thus used for statistical studies such as those required for tests of galaxy formation.

Kathryn V. Johnston; Penny D. Sackett; James S. Bullock
2001-04-12

500

The Alignment between Satellites and Central Galaxies: Theory vs. Observations

  Astrophysics (arXiv)

Summary: Recent studies have shown that the distribution of satellite galaxies is preferentially aligned with the major axis of their central galaxy. The strength of this alignment has been found to depend strongly on the colours of the satellite and central galaxies, and only weakly on the mass of the halo in which the galaxies reside. In this paper we study whether these alignment signals, and their dependence on galaxy and halo properties, can be reproduced in a hierarchical structure formation model of a $\\Lambda$CDM concordance cosmology. To that extent we use a large $N$-body simulation which we populate with galaxies following a semi-analytical model for galaxy formation. We find that if the orientation of the central galaxy is perfectly aligned with that of its dark matter halo, then the predicted central-satellite alignment signal is much stronger than observed. If, however, the minor axis of a central galaxy is perfectly aligned with the angular momentum vector of its dark matter halo, we can accurately reproduce the observed alignment strength as function of halo mass and galaxy color. Although this suggests that the orientation of central galaxies is governed by the angular momentum of their dark matter haloes, we emphasize that any other scenario in which the minor axes of central galaxy and halo are misaligned by $\\sim 40^{\\circ}$ (on average) will match the data equally well. Finally, we show that dependence of the alignment strength on the color of the central galaxy is most likely an artefact due to interlopers in the group catalogue. The dependence on the color of the satellite galaxies, on the other hand, is real and owes to the fact that red satellites are associated with subhaloes that were more massive at their time of accretion.

X. Kang; Frank C. van den Bosch; Xiaohu Yang; Shude Mao; H. J. Mo; Cheng Li; Y. P. Jing
2007-04-24

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