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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired Solar Fuel ProductionRecoverable UserTeacherTechLab TechLab
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Codes How to compile and link MPI codes on Euclid. Read More Using the ACML Math Library How to compile and link a code with the ACML library and include the ACML...
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File storage File storage Disk Quota Change Request Form Euclid File Systems Euclid has 3 kinds of file systems available to users: home directories, scratch directories and...
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Software and Tools Software and Tools The table below shows the software installed on Euclid that is managed by modules. Package Category Version Module Install Date Date Made...
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node system with 48 processors. It supports both multiprocessing (MPI) and multithreading programming models. Interactive Jobs All Euclid jobs are interactive. To launch an MPI...
Le Roy, Robert J.
1999 Solutions Euclid Contest (Grade12) for the Awards Canadian Mathematics Competition An activity of The Centre for Education in Mathematics and Computing, University of Waterloo, Waterloo, Ontario © 1999 Waterloo Mathematics Foundation #12;1999 Euclid Solutions 2 1. (a) If x 1 1 1 3 4= + , what
Kitching, Thomas D; Brown, Michael L; Bull, Philip; McEwen, Jason D; Oguri, Masamune; Scaramella, Roberto; Takahashi, Keitaro; Wu, Kinwah; Yamauchi, Daisuke
2015-01-01
Over the past few years two of the largest and highest fidelity experiments conceived have been approved for construction: Euclid is an ESA M-Class mission that will map three-quarters of the extra galactic sky with Hubble Space Telescope resolution optical and NIR imaging, and NIR spectroscopy, its scientific aims (amongst others) are to create a map of the dark Universe and to determine the nature of dark energy. The Square Kilometre Array (SKA) has similar scientific aims (and others) using radio wavelength observations. The two experiments are synergistic in several respects, both through the scientific objectives and through the control of systematic effects. SKA Phase-1 and Euclid will be commissioned on similar timescales offering an exciting opportunity to exploit synergies between these facilities.
Euclid's Algorithm, Guass' Elimination and Buchberger's Algorithm
International Association for Cryptologic Research (IACR)
Euclid's Algorithm, Guass' Elimination and Buchberger's Algorithm Shaohua Zhang School of Mathematics, Shandong University, Jinan, Shandong, 250100, PRC Abstract: It is known that Euclid's algorithm, Guass' elimination and Buchberger's algorithm play important roles in algorithmic number the- ory
Euclid Asteroseismology and Kuiper Belt Objects
Gould, A; Stello, D
2015-01-01
Euclid, which is primarily a dark-energy/cosmology mission, may have a microlensing component, consisting of perhaps four dedicated one-month campaigns aimed at the Galactic bulge. We show that such a program would yield excellent auxilliary science, including asteroseimology detections for about 100,000 giant stars, and detection of about 1000 Kuiper Belt Objects (KBOs), down to 2--2.5 mag below the observed break in the KBO luminosity function at I ~26. For the 400 KBOs below the break, Euclid will measure accurate orbits, with fractional period errors <~ 2.5%.
El Algoritmo de Euclides Pablo L. De Napoli
De Nápoli, Pablo Luis
El Algoritmo de Euclides Pablo L. De N´apoli Departamento de Matem´atica Facultad de Ciencias Matem´atica Facultad de Ciencias Exactas y Naturales Universidad de Buenos Aires )El Algoritmo de Euclides 25 de abril de 2014 1 / 23 #12;Parte I El algoritmo de Euclides Pablo L. De N´apoli (Departamento
Algoritmo di Euclide, numeri di Fibonacci e frazioni continue
Zaccagnini, Alessandro
Algoritmo di Euclide, numeri di Fibonacci e frazioni continue Alessandro Zaccagnini Sommario positivi, si descrive l'Algoritmo di Euclide e se ne fa un'analisi di complessit`a parziale, scoprendo che continue periodiche hanno valore irrazionale quadratico. 1 L'Algoritmo di Euclide Problema 1 Determinare il
Euclid, Ohio: Energy Resources | Open Energy Information
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Cosmology and fundamental physics with the Euclid satellite
Luca Amendola; Stephen Appleby; David Bacon; Tessa Baker; Marco Baldi; Nicola Bartolo; Alain Blanchard; Camille Bonvin; Stefano Borgani; Enzo Branchini; Clare Burrage; Stefano Camera; Carmelita Carbone; Luciano Casarini; Mark Cropper; Claudia deRham; Cinzia di Porto; Anne Ealet; Pedro G. Ferreira; Fabio Finelli; Juan Garcia-Bellido; Tommaso Giannantonio; Luigi Guzzo; Alan Heavens; Lavinia Heisenberg; Catherine Heymans; Henk Hoekstra; Lukas Hollenstein; Rory Holmes; Ole Horst; Knud Jahnke; Thomas D. Kitching; Tomi Koivisto; Martin Kunz; Giuseppe La Vacca; Marisa March; Elisabetta Majerotto; Katarina Markovic; David Marsh; Federico Marulli; Richard Massey; Yannick Mellier; David F. Mota; Nelson Nunes; Will Percival; Valeria Pettorino; Cristiano Porciani; Claudia Quercellini; Justin Read; Massimiliano Rinaldi; Domenico Sapone; Roberto Scaramella; Constantinos Skordis; Fergus Simpson; Andy Taylor; Shaun Thomas; Roberto Trotta; Licia Verde; Filippo Vernizzi; Adrian Vollmer; Yun Wang; Jochen Weller; Tom Zlosnik
2015-10-22
Euclid is a European Space Agency medium class mission selected for launch in 2019 within the Cosmic Vision 2015-2025 programme. The main goal of Euclid is to understand the origin of the accelerated expansion of the Universe. Euclid will explore the expansion history of the Universe and the evolution of cosmic structures by measuring shapes and redshifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky. Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis. This review has been planned and carried out within Euclid's Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.
Cosmology and fundamental physics with the Euclid satellite
Luca Amendola; Stephen Appleby; David Bacon; Tessa Baker; Marco Baldi; Nicola Bartolo; Alain Blanchard; Camille Bonvin; Stefano Borgani; Enzo Branchini; Clare Burrage; Stefano Camera; Carmelita Carbone; Luciano Casarini; Mark Cropper; Claudia deRham; Cinzia di Porto; Anne Ealet; Pedro G. Ferreira; Fabio Finelli; Juan Garcia-Bellido; Tommaso Giannantonio; Luigi Guzzo; Alan Heavens; Lavinia Heisenberg; Catherine Heymans; Henk Hoekstra; Lukas Hollenstein; Rory Holmes; Ole Horst; Knud Jahnke; Thomas D. Kitching; Tomi Koivisto; Martin Kunz; Giuseppe La Vacca; Marisa March; Elisabetta Majerotto; Katarina Markovic; David Marsh; Federico Marulli; Richard Massey; Yannick Mellier; David F. Mota; Nelson Nunes; Will Percival; Valeria Pettorino; Cristiano Porciani; Claudia Quercellini; Justin Read; Massimiliano Rinaldi; Domenico Sapone; Roberto Scaramella; Constantinos Skordis; Fergus Simpson; Andy Taylor; Shaun Thomas; Roberto Trotta; Licia Verde; Filippo Vernizzi; Adrian Vollmer; Yun Wang; Jochen Weller; Tom Zlosnik
2012-06-06
Euclid is a European Space Agency medium class mission selected for launch in 2019 within the Cosmic Vision 2015-2025 programme. The main goal of Euclid is to understand the origin of the accelerated expansion of the Universe. Euclid will explore the expansion history of the Universe and the evolution of cosmic structures by measuring shapes and redshifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky. Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis. This review has been planned and carried out within Euclid's Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.
Annual Postdoctoral Research and Career Symposium | Argonne National...
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Chicago Council on Science and Technology, Clean Energy Trust, Euclid TechLabs, Exxon Mobil, Illinois Science and Technology Coalition, Illinois Technology Association,...
Galaxy formation history through hod model from euclid mock catalogs
Sakr, Ziad
2015-01-01
Halo Occupation Distribution (HOD) is a model giving the average number of galaxies in a dark matter halo, function of its mass and other intrinsic properties, like distance from halo center, luminosity and redshift of its constituting galaxies. It is believed that these parameters could also be related to the galaxy history of formation. We want to investigate more this relation in order to test and better refine this model. To do that, we extract HOD indicators from EUCLID mock catalogs for different luminosity cuts and for redshifts ranges going from 0.1 formation history following the idea that galaxy evolution is the combination rather than the conflict of the two main proposed ideas nowadays: the older hierarchical mass merger driven paradigm and the recent downsizing star formation driven approach.
standing on the other is called a perpendicular to that on which it stands. An obtuse angle is an angle greater than a right angle. An acute angle is an angle less ...
Jain, B.; Spergel, D.; Connolly, A.; Dell'antonio, I.; Frieman, J.; Gawiser, E.; Gehrels, N.; Gladney, L.; Heitmann, K.; Helou, G.; Hirata, C.; Ho, S.; Ivezic, Z.; Jarvis, M.; Kahn, S.; Kalirai, J.; Kim, A.; Lupton, R.; Mandelbaum, R.; Marshall, P.; Newman, J. A.; Postman, M.; Rhodes, J.; Strauss, M. A.; Tyson, J. A.; Wood-Vesey, W. M.
2015-02-02
The scientific opportunity offered by the combination of data from LSST, WFIRST and Euclid goes well beyond the science enabled by any one of the data sets alone. The range in wavelength, angular resolution and redshift coverage that these missions jointly span is remarkable. With major investments in LSST and WFIRST, and partnership with ESA in Euclid, the US has an outstanding scientific opportunity to carry out a combined analysis of these data sets. It is imperative for us to seize it and, together with our European colleagues, prepare for the defining cosmological pursuit of the 21st century. The main argument for conducting a single, high-quality reference co-analysis exercise and carefully documenting the results is the complexity and subtlety of systematics that define this co-analysis. Falling back on many small efforts by different teams in selected fields and for narrow goals will be inefficient, leading to significant duplication of effort.
Hamolli, Lindita; De Paolis, Francesco; Nucita, Achille A
2015-01-01
In recent years free-loating planets (FFPs) have drawn a great interest among astrophysicists. Gravitational microlensing is a unique and exclusive method for their investigation which may allow obtaining precious information about their mass and spatial distribution. The planned Euclid space-based observatory will be able to detect a substantial number of microlensing events caused by FFPs towards the Galactic bulge. Making use of a synthetic population algorithm, we investigate the possibility of detecting finite source effects in simulated microlensing events due to FFPs. We find a significant efficiency for finite source effect detection that turns out to be between 20% and 40% for a FFP power law mass function index in the range [0.9, 1.6]. For many of such events it will also be possible to measure the angular Einstein radius and therefore constrain the lens physical parameters. These kinds of observations will also offer a unique possibility to investigate the photosphere and atmosphere of Galactic bul...
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example.x example.c For C++ source code use mpiCC: % mpiCC -o example.x example.C PGI Compilers (CC++Fortran) See PGI compiler for information about this compiler. GNU Compilers...
Beligiannis, Apostolos
Digital Library 1 and as for the drawings I have reproduced with a geometrical drawing language named on David Joyce's Euclid's Elements Web Page 3 . At the Perseus Digital Library each word is linked. But the digitalized version, and especially the morphological tools serviced on Perseus Digital Library are protected
Euclid Hardware and Software Configuration
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and has 873 TB of disk space, with a peak IO bandwidth of 15 GBs User Environment Compilers Portland Group Fortran, C, and C++ GNU Fortran, C, and C++ Programming Models MPI...
Using the ACML Math Library on Euclid
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of your compilelink line: % module load acml % mpicc -o cblas cblas.c ACML If you have the gnu compilers loaded, use the acml-gnu module instead. Last edited: 2011-04-06 13:02:19...
Euclid and Wythoff games Aviezri S. Fraenkel
precisely for all y in the closed integer interval [ nx , n+1x ]. For computing the g-function it thus suffices to compute the boundary points nx . (For n Z>0, nx = 1 + nx ; 0 = 1, 1 the golden section.) In this note we present two characterizations of the extremal points nx , which also reveal, incidentally
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformation Current HABFES October 27th,EnvironmentalEqual7/31/2016 Version No.:Contract
South Euclid, Ohio: Energy Resources | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page| Open Energy Information Serbia-Enhancing Capacity forSiliciumEnergy IncAshburnham,BoundChicagoEl Monte,Eliot,
PGI version 11.3 available on Euclid
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access toOctoberConsumptionPoweredEAnnouncements Â» PGI version 11.3
DOE ZERH Case Study: Heirloom Design Build, Euclid Avenue, Atlanta, GA
none,
2015-09-01
Case study of a DOE 2015 Housing Innovation Award winning custom home in the mixed-humid climate that got a HERS 50 without PV, with 2x6 16” on center walls with R-19 ocsf; basement with R-28 ccsf, R-5 rigid foam under slab; sealed attic with R-28 ocsf under roof deck; 22.8 SEER; 12.5 HSPF heat pump.
DOE Tour of Zero: Euclid Avenue by Heirloom Design Build | Department of
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DOE Zero Energy Ready Home Case Study: Heirloom Design Build, Euclid
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DOE Tour of Zero Floorplans: Euclid Avenue by Heirloom Design Build |
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum Based| Department8, 2015 GATEWAY Takes onandField |of EnergyDepartment of
HIA 2015 DOE Zero Energy Ready Home Case Study: Heirloom Design Build, Euclid Avenue, Atlanta, GA
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum12,ExecutiveFinancing Programs |Reference StationFranklinHammer and Hand
DOE Tour of Zero: Euclid Avenue by Heirloom Design Build | Department of
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann JacksonDepartment of Energy Facilities By E-mail:Carly Wilkins(Part 1)DOE14 KB Home
arXiv:1501.03978v1[astro-ph.CO]16Jan2015 Euclid & SKA Synergies
McEwen, Jason
and to determine the nature of dark energy. The Square Kilometre Array (SKA) has similar scientific aims (and between these facilities. Advancing Astrophysics with the Square Kilometre Array June 8-13, 2014 Giardini
Gold, Steven H.
2013-10-13
This is the final report on the research program ?Development and Testing of Advanced Accelerator Structures and Technologies at 11.424 GHz,? which was carried out by the Naval Research Laboratory (NRL) under Interagency Agreement DE?AI02?01ER41170 with the Department of Energy. The period covered by this report is 15 July 2010 ? 14 July 2013. The program included two principal tasks. Task 1 involved a study of the key physics issues related to the use of high gradient dielectric-loaded accelerating (DLA) structures in rf linear accelerators and was carried out in collaboration with Argonne National Laboratory (ANL) and Euclid Techlabs LLC. Task 2 involved a study of high power active microwave pulse compressors and was carried out in collaboration with Omega-P, Inc. and the Institute of Applied Physics of the Russian Academy of Sciences in Nizhny Novgorod. The studies under Task 1 were focused on rf-induced multipactor and breakdown in externally driven DLA structures at the 200-ns timescale. Suppression of multipactor and breakdown are essential to the practical application of dielectric structures in rf linear accelerators. The structures that were studied were developed by ANL and Euclid Techlabs and their performance was evaluated at high power in the X-band Magnicon Laboratory at NRL. Three structures were designed, fabricated, and tested, and the results analyzed in the first two years of the program: a clamped quartz traveling-wave (TW) structure, a externally copper-coated TW structure, and an externally copper-coated dielectric standing-wave (SW) structure. These structures showed that rf breakdown could be largely eliminated by eliminating dielectric joints in the structures, but that the multipactor loading was omnipresent. In the third year of the program, the focus of the program was on multipactor suppression using a strong applied axial magnetic field, as proposed by Chang et al. [C. Chang et al., J. Appl. Phys. 110, 063304 (2011).], and a successful experiment was carried out that demonstrated suppression of multipactor in the uniform-field region of a TW DLA structure. However, in accordance with theory, the multipactor was enhanced in regions of the structure with lower values of axial magnetic field. Under Task 2, there were two two-month experimental runs at NRL that were used to characterize the performance of high power two-channel dual-mode active microwave pulse compressor configurations that used electron-beam triggered switch cavities. The pulse compressors were designed and fabricated by Omega-P, Inc. and the Russian Institute of Applied Physics and tested in the Magnicon Laboratory at NRL. These pulse compressors made use of an electron beam discharge from a cylindrical knife-edged Mo cathode coated with a CVD diamond film that was driven by a ?100 kV, 100 ns high voltage pulse. The electron beam was used to change the resonant frequency of the switch cavities in order to create the output microwave pulse. The compressor channels included a TE01 input and output section and a TE02 energy storage cavity, followed by a switch assembly that controlled the coupling between the TE01 and TE02 modes. In the initial state, the switch cavity was in resonance, the reflection from the cavity was out of phase, and the mode conversion was only ~2-3%, allowing the energy storage cavity to fill. When the electron beam was discharged into the switch cavity, the cavity was shifted out of resonance, causing the phase of the reflection to change by ~?. As a result of the change in the reflection phase, the mode coupling in the conical taper was greatly increased, and could approach ~100%, permitting the energy storage cavity to empty in one cavity round trip time of the TE02 mode to produce a high power output pulse. The second experiment runs demonstrated a 190 MW, ~20 ns compressed pulse at 25.7 gain and ~50% efficiency, using a 7.4 MW, 1 ?s drive pulse from the magnicon. The success of this experiment suggests a path to future high gain active versions of the SLED 2 pulse compressor at SLAC.
be the diameter passing through E. Then, a special case of the proposition is to show that AE · EB = FE · EG. In fact, it is enough to show this special case, because if AE · EB = FE · EG and if CE · ED = FE · EG, then by transitivity, AE · EB = CE · ED. Hence, we will proceed to prove that AE · EB = FE · EG. Let r be the radius
Fermilab-Conf-15-175-APC ENERGY DEPOSITION AND RADIOLOGICAL STUDIES FOR THE LBNF
Fermilab-Conf-15-175-APC April 2015 ENERGY DEPOSITION AND RADIOLOGICAL STUDIES FOR THE LBNF HADRON TechLabs, LLC, Solon, OH 44139, USA Abstract Results of detailed Monte Carlo energy deposition11359 with the U.S. Department of Energy. § Presented at the 6th International Particle Accelerator
Erickson, Sandra Sassetti Fernandes
1990-01-01
known) fictions inspired by Q~~m. In" rr I fin I m n de Mario Vargas Llosa: un estudio transtextual, " Marcos Leopoldo Bernucci discussed a variety of texts used by Llosa in the writing of ~Lrr~. In this study Bernucci examined the relationship... American Case Studies, " and Marcos Leopoldo Bernucci, " ' de Mario Vargas Llosa: Un estudio transtextual. " , and is suggested in Llosa's text itself by Gall's phrenology, a major theme of Hegel's P~hn~m~~nlggy. Both in regard to ~~ and La~~rr we...
Language and Framework Support for Reviewably-Secure Software Systems
Mettler, Adrian Matthew
2012-01-01
1.1.2 Programming Languages and Abstractions . . . . . . . .security properties. Languages and programming idioms thatJ. Popek. Report on the programming language Euclid. SIGPLAN
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announcements PGI version 11.3 available on Euclid http:www.nersc.govuserscomputational-systemsretired-systemseuclid-retired-01-31-2013updates-and-statusannouncements...
Pacific Fuel Cell Corporation | Open Energy Information
Fuel Cell Corporation Jump to: navigation, search Name: Pacific Fuel Cell Corporation Address: 26985 Lakeland Blvd. Place: Euclid, Ohio Zip: 44132 Sector: Buildings, Efficiency,...
Ralph Kaufmann
Study Guide Timeline. Euclid's five axioms (300 BC); From Proclus (400AD) belief that the fifth axiom is derivable from the first four; Saccheri (17th century): ...
Directions & Parking School of Information Studies
Crowston, Kevin
Directions & Parking School of Information Studies Syracuse University Hinds Hall 100 University Street will be on your right.) Take Adams Street up the hill until it dead ends into Ostrom Avenue Take a right on Ostrom Avenue Take a right on Euclid Avenue Continue on Euclid across Comstock Avenue
Increasing the transformer ratio at the Argonne wakefield accelerator.
Power, J.G.; Conde, M.; Liu, W.; Yusof, Z.; Gai, W.; Jing, C.; Kanareykin, A. (High Energy Physics); (Euclid Techlabs, LLC)
2011-01-01
The transformer ratio is defined as the ratio of the maximum energy gain of the witness bunch to the maximum energy loss experienced by the drive bunch (or a bunch within a multidrive bunch train). This plays an important role in the collinear wakefield acceleration scheme. A high transformer ratio is desirable since it leads to a higher overall efficiency under similar conditions (e.g. the same beam loading, the same structure, etc.). One technique to enhance the transformer ratio beyond the ordinary limit of 2 is to use a ramped bunch train. The first experimental demonstration observed a transformer ratio only marginally above 2 due to the mismatch between the drive microbunch length and the frequency of the accelerating structure [C. Jing, A. Kanareykin, J. Power, M. Conde, Z. Yusof, P. Schoessow, and W. Gai, Phys. Rev. Lett. 98, 144801 (2007)]. Recently, we revisited this experiment with an optimized microbunch length using a UV laser stacking technique at the Argonne Wakefield Accelerator facility and measured a transformer ratio of 3.4. Measurements and data analysis from these experiments are presented in detail.
Cover of 1962 Former Students Directory
Unknown
2011-08-17
The Truck Receiving Dock 66 at the General Motors Fisher Body Division Plant in Euclid, Ohio had always been a source of constant employee complaints during the heating season. Despite management's efforts to maintain as uniform a temperature...
Carver Email Announcements Archive
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Next Tuesday 2012-02-03 16:30:16 David Turner
Perry Luksin | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
The State Energy Program Helps Promote that Bigger IS Better in Euclid, Ohio July 25 Turkey Hill Dairy: Where Energy is Not Left Flapping in the Wind December 21 Farming Out Heat...
Li, Haizhong
of Project Euclid (Cornell University Library), an aggregation of electronic journals. It is available online classification of the Lagrangian submanifolds in 3-dimensional complex space forms with isotropic cubic tensor. 1 Mathematics Subject Classification : Primary 53C20; Secondary 53C42. Key words and phrases : Lagrangian
S. Bhunia, PhD Curriculum Vitae Page 1 of 12 Feb 1, 2015 Swarup Bhunia, Ph.D.
Bhunia, Swarup
University 10900 Euclid Ave., 711 Glennan Building Cleveland, OH 44106-7221 Phone: +1 (216) 368-5550 Fax: +1 Sasken Communication Technologies Limited [formerly, Silicon Automation Systems, Inc. (SAS)] Bangalore nomination in Asia and South Pacific Design Automation Conf. (ASP-DAC) 2005 Semiconductor Research
UP TO 100,000 RELIABLE STRONG GRAVITATIONAL LENSES IN FUTURE DARK ENERGY EXPERIMENTS
Serjeant, S.
2014-09-20
The Euclid space telescope will observe ?10{sup 5} strong galaxy-galaxy gravitational lens events in its wide field imaging survey over around half the sky, but identifying the gravitational lenses from their observed morphologies requires solving the difficult problem of reliably separating the lensed sources from contaminant populations, such as tidal tails, as well as presenting challenges for spectroscopic follow-up redshift campaigns. Here I present alternative selection techniques for strong gravitational lenses in both Euclid and the Square Kilometre Array, exploiting the strong magnification bias present in the steep end of the H? luminosity function and the H I mass function. Around 10{sup 3} strong lensing events are detectable with this method in the Euclid wide survey. While only ?1% of the total haul of Euclid lenses, this sample has ?100% reliability, known source redshifts, high signal-to-noise, and a magnification-based selection independent of assumptions of lens morphology. With the proposed Square Kilometre Array dark energy survey, the numbers of reliable strong gravitational lenses with source redshifts can reach 10{sup 5}.
Astronomy Advisory Panel Richard Bower, Michael Brown, Anthony
Crowther, Paul
over 10 years Many UK science areas: dark energy/matter, galactic structure, transients, solar systemAstronomy Advisory Panel Richard Bower, Michael Brown, Anthony Challinor, Chris Evans, Paul O;High priority - maintain innovation Provide science for VLT, ALMA, E-ELT, SKA, GAIA, JWST, Euclid
THE TETHERING ARM OF THE EGF RECEPTOR IS REQUIRED FOR NEGATIVE COOPERATIVITY AND SIGNAL TRANSDUCTION
Pike, Linda J.
1 THE TETHERING ARM OF THE EGF RECEPTOR IS REQUIRED FOR NEGATIVE COOPERATIVITY AND SIGNAL receptor tethering arm Address correspondence to: Linda J. Pike, 660 South Euclid Ave., Box 8231, St. Louis in which the dimerization arm of subdomain II interacts with the tethering arm in subdomain IV. Following
Lyu, Michael R.
Comparative Studies on Feature Extraction Methods for Multispectral Remote Sensing Image, it is necessary to study methods regarding how to extract the main features of the image effectively to extract the most available features. These methods include the Euclid distance measurement (EDM
Beukers, Frits
algoritme. Neem bijvoorbeeld 25 7 en pas het Euclidisch algoritme toe op 25 en 7, 25 = 3 Â· 7 + 4 7 = 1 Â· 4 algoritme van Euclides, a = a0b + r1 0 r1 dat het algoritme oneindig lang doorgaat, want we kunnen steeds weer n+1 = 1/{n} nemen. Aldus krijgen
Simon, Dan
, is the leading cause of death among firefighters in the United States [1]. The need to carry heavy equipment long) (1) (3) (1) (1) Cleveland State University, 2121 Euclid Ave, Cleveland, Ohio 44115 (2) Arcon software produces a diagnostic-friendly ECG signal and then determines the patient's heart rate. When
Instituto Superior Tecnico Departamento de Matematica
Cannas da Silva, Ana
vectorial; fâ??ormula de Euler, poliedros regulares Semana 6 Postulados de Euclides; coordenadas polares, cilâ?ºcoÂtempo (3Â12 Junho) Semana 13 Introduâ?ºcâ?ao a mecâ??anica geomâ??etrica e relatividade especial #12; GEOMETRIA I
Masters, Daniel; Stern, Daniel; Ilbert, Olivier; Salvato, Mara; Schmidt, Samuel; Longo, Giuseppe; Rhodes, Jason; Paltani, Stephane; Mobasher, Bahram; Hoekstra, Henk; Hildebrandt, Hendrik; Coupon, Jean; Steinhardt, Charles; Speagle, Josh; Faisst, Andreas; Kalinich, Adam; Brodwin, Mark; Brescia, Massimo; Cavuoti, Stefano
2015-01-01
Calibrating the photometric redshifts of >10^9 galaxies for upcoming weak lensing cosmology experiments is a major challenge for the astrophysics community. The path to obtaining the required spectroscopic redshifts for training and calibration is daunting, given the anticipated depths of the surveys and the difficulty in obtaining secure redshifts for some faint galaxy populations. Here we present an analysis of the problem based on the self-organizing map, a method of mapping the distribution of data in a high-dimensional space and projecting it onto a lower-dimensional representation. We apply this method to existing photometric data from the COSMOS survey selected to approximate the anticipated Euclid weak lensing sample, enabling us to robustly map the empirical distribution of galaxies in the multidimensional color space defined by the expected Euclid filters. Mapping this multicolor distribution lets us determine where - in galaxy color space - redshifts from current spectroscopic surveys exist and whe...
Aquifer behavior with reinjection
Bonet, Euclides Jose
1967-01-01
AQUIFER BEHAVIOR WITH REINJECTION A Thesis By EUCLIDES JOSE BONET Submitted to the Graduate College of the Texas ARUM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May, f967 Major Subject... Petroleum Engineering AQUIFER BEHAVIOR WITH REINJECTION A Thesis By E UC LI DES JOSE BONE T Approved as to style and content by: (Chairman of Committee) (Member) (Member) May, 1967 ACKNOWLEDGMENT Thanks are due to Petroleo Brasilerio S...
Probing primordial non-Gaussianity consistency relation with galaxy surveys
Daisuke Yamauchi; Keitaro Takahashi
2015-10-06
With a radio continuum galaxy survey by Square Kilometre Array (SKA), a photometric galaxy survey by Euclid and their combination, we forecast future constraints on primordial non-Gaussianity. We focus on the potential impact of local-type higher-order nonlinear parameters on the parameter estimation and particularly the confirmation of the inflationary consistency inequality. Non-standard inflationary models, such as multi-field models, introduce the scale-dependent stochastic clustering of galaxies on large scales, which is a unique probe of mechanism for generating primordial density fluctuations. Our Fisher matrix analysis indicates that a deep and wide survey provided by SKA is more advantageous to constrain $\\tau_{\\rm NL}$, while Euclid has a strong constraining power for $f_{\\rm NL}$ due to the redshift information, suggesting that the joint analysis between them are quite essential to break the degeneracy between $f_{\\rm NL}$ and $\\tau_{\\rm NL}$. The combination of full SKA and Euclid will achieve the precision level needed to confirm the consistency inequality even for $f_{\\rm NL}\\approx 0.9$ and $\\tau_{\\rm NL}\\approx 8$, though it is still hard for a single survey to confirm it when $f_{\\rm NL}\\lesssim 1.5$.
Probing primordial non-Gaussianity consistency relation with galaxy surveys
Yamauchi, Daisuke
2015-01-01
With a radio continuum galaxy survey by Square Kilometre Array (SKA), a photometric galaxy survey by Euclid and their combination, we forecast future constraints on primordial non-Gaussianity. We focus on the potential impact of local-type higher-order nonlinear parameters on the parameter estimation and particularly the confirmation of the inflationary consistency inequality. Non-standard inflationary models, such as multi-field models, introduce the scale-dependent stochastic clustering of galaxies on large scales, which is a unique probe of mechanism for generating primordial density fluctuations. Our Fisher matrix analysis indicates that a deep and wide survey provided by SKA is more advantageous to constrain $\\tau_{\\rm NL}$, while Euclid has a strong constraining power for $f_{\\rm NL}$ due to the redshift information, suggesting that the joint analysis between them are quite essential to break the degeneracy between $f_{\\rm NL}$ and $\\tau_{\\rm NL}$. The combination of full SKA and Euclid will achieve the...
Applications of DMDs for astrophysical research
Robberto, M; Jacobsen, A; Zamkotsian, F; Zerbi, F M; 10.1117/12.809542
2009-01-01
A long-standing problem of astrophysical research is how to simultaneously obtain spectra of thousands of sources randomly positioned in the field of view of a telescope. Digital Micromirror Devices, used as optical switches, provide a most powerful solution allowing to design a new generation of instruments with unprecedented capabilities. We illustrate the key factors (opto-mechanical, cryo-thermal, cosmic radiation environment,...) that constrain the design of DMD-based multi-object spectrographs, with particular emphasis on the IR spectroscopic channel onboard the EUCLID mission, currently considered by the European Space Agency for a 2017 launch date.
Atrio-Barandela, F.; Kashlinsky, A. E-mail: Alexander.Kashlinsky@nasa.gov
2014-12-20
The epoch of first star formation and the state of the intergalactic medium (IGM) at that time are not directly observable with current telescopes. The radiation from those early sources is now part of the cosmic infrared background (CIB) and, as these sources ionize the gas around them, the IGM plasma would produce faint temperature anisotropies in the cosmic microwave background (CMB) via the thermal Sunyaev-Zeldovich (TSZ) effect. While these TSZ anisotropies are too faint to be detected, we show that the cross-correlation of maps of source-subtracted CIB fluctuations from Euclid, with suitably constructed microwave maps at different frequencies, can probe the physical state of the gas during reionization and test/constrain models of the early CIB sources. We identify the frequency-combined, CMB-subtracted microwave maps from space- and ground-based instruments to show that they can be cross-correlated with the forthcoming all-sky Euclid CIB maps to detect the cross-power at scales ?5'-60' with signal-to-noise ratios (S/Ns) of up to S/N ? 4-8 depending on the contribution to the Thomson optical depth during those pre-reionization epochs (?? ? 0.05) and the temperature of the IGM (up to ?10{sup 4} K). Such a measurement would offer a new window to explore the emergence and physical properties of these first light sources.
Fitting and forecasting non-linear coupled dark energy
Casas, Santiago; Baldi, Marco; Pettorino, Valeria; Vollmer, Adrian
2015-01-01
We consider cosmological models in which dark matter feels a fifth force mediated by the dark energy scalar field, also known as coupled dark energy. Our interest resides in estimating forecasts for future surveys like Euclid when we take into account non-linear effects, relying on new fitting functions that reproduce the non-linear matter power spectrum obtained from N-body simulations. We obtain fitting functions for models in which the dark matter-dark energy coupling is constant. Their validity is demonstrated for all available simulations in the redshift range $z=0-1.6$ and wave modes below $k=10 \\text{h/Mpc}$. These fitting formulas can be used to test the predictions of the model in the non-linear regime without the need for additional computing-intensive N-body simulations. We then use these fitting functions to perform forecasts on the constraining power that future galaxy-redshift surveys like Euclid will have on the coupling parameter, using the Fisher matrix method for galaxy clustering (GC) and w...
Complementarity of Future Dark Energy Probes
Jiayu Tang; Filipe B. Abdalla; Jochen Weller
2008-07-20
In recent years a plethora of future surveys have been suggested to constrain the nature of dark energy. In this paper we adapt a binning approach to the equation of state factor ``w'' and discuss how future weak lensing, galaxy cluster counts, Supernovae and baryon acoustic oscillation surveys constrain the equation of state at different redshifts. We analyse a few representative future surveys, namely DES, PS1, WFMOS, PS4, EUCLID, SNAP and SKA, and perform a principal component analysis for the ``w'' bins. We also employ a prior from Planck cosmic microwave background measurements on the remaining cosmological parameters. We study at which redshifts a particular survey constrains the equation of state best and how many principal components are significantly determined. We then point out which surveys would be sufficiently complementary. We find that weak lensing surveys, like EUCLID, would constrain the equation of state best and would be able to constrain of the order of three significant modes. Baryon acoustic oscillation surveys on the other hand provide a unique opportunity to probe the equation of state at relatively high redshifts.
Measuring primordial non-Gaussianity through weak lensing peak counts
Laura Marian; Stefan Hilbert; Robert E. Smith; Peter Schneider; Vincent Desjacques
2012-04-18
We explore the possibility of detecting primordial non-Gaussianity of the local type using weak lensing peak counts. We measure the peak abundance in sets of simulated weak lensing maps corresponding to three models f_NL={0, +100, -100}. Using survey specifications similar to those of Euclid and without assuming any knowledge of the lens and source redshifts, we find the peak functions of the non-Gaussian models with f_NL=+-100 to differ by up to 15% from the Gaussian peak function at the high-mass end. For the assumed survey parameters, the probability of fitting an f_NL=0 peak function to the f_NL=+-100 peak functions is less than 0.1%. Assuming the other cosmological parameters known, f_NL can be measured with an error \\Delta f_NL ~ 13. It is therefore possible that future weak lensing surveys like Euclid and LSST may detect primordial non-Gaussianity from the abundance of peak counts, and provide complementary information to that obtained from the cosmic microwave background.
Summary of the DUNE Mission Concept
Refregier, Alexandre
2008-01-01
The Dark UNiverse Explorer (DUNE) is a wide-field imaging mission concept whose primary goal is the study of dark energy and dark matter with unprecedented precision. To this end, DUNE is optimised for weak gravitational lensing, and also uses complementary cosmolo gical probes, such as baryonic oscillations, the integrated Sachs-Wolf effect, a nd cluster counts. Immediate additional goals concern the evolution of galaxies, to be studied with groundbreaking statistics, the detailed structure of the Milky Way and nearby galaxies, and the demographics of Earth-mass planets. DUNE is a medium class mission consisting of a 1.2m telescope designed to carry out an all-sky survey in one visible and three NIR bands (1deg$^2$ field-of-view) which will form a unique legacy for astronomy. DUNE has been selected jointly with SPACE for an ESA Assessment phase which has led to the Euclid merged mission concept.
Summary of the DUNE Mission Concept
Alexandre Refregier; Marian Douspis; the DUNE collaboration
2008-07-25
The Dark UNiverse Explorer (DUNE) is a wide-field imaging mission concept whose primary goal is the study of dark energy and dark matter with unprecedented precision. To this end, DUNE is optimised for weak gravitational lensing, and also uses complementary cosmolo gical probes, such as baryonic oscillations, the integrated Sachs-Wolf effect, a nd cluster counts. Immediate additional goals concern the evolution of galaxies, to be studied with groundbreaking statistics, the detailed structure of the Milky Way and nearby galaxies, and the demographics of Earth-mass planets. DUNE is a medium class mission consisting of a 1.2m telescope designed to carry out an all-sky survey in one visible and three NIR bands (1deg$^2$ field-of-view) which will form a unique legacy for astronomy. DUNE has been selected jointly with SPACE for an ESA Assessment phase which has led to the Euclid merged mission concept.
Is spacetime absolutely or just most probably Lorentzian?
Aharon Davidson; Ben Yellin
2015-09-03
An algebraic evolution equation for the lapse function $n(t)$, the result of a tenable pre-gauging of the cosmological scale factor $a(t)$, signals a non-dynamical mini-superspace. The missing ingredient, a generalized momentum enjoying canonical Dirac (rather than Poisson) brackets with $n(t)$, calls for measure scaling. Contrary to the Hartle-Hawking approach: (i) The static wave function $\\psi(a)$ is traded for an explicit time dependent $\\psi(n, t)$, (ii) The 'most classical' cosmological wave packet is dominated by the classic FLRW configuration, and (iii) The Euclid/Lorentz crossover gets quantum mechanically smeared. A correspondence with the classical/quantum 5-dim Schwarzschild-deSitter black hole is noted.
Dark energy properties from large future galaxy surveys
Basse, Tobias; Bjælde, Ole Eggers; Hannestad, Steen; Hamann, Jan; Wong, Yvonne Y.Y. E-mail: oeb@phys.au.dk E-mail: sth@phys.au.dk
2014-05-01
We perform a detailed forecast on how well a Euclid-like survey will be able to constrain dark energy and neutrino parameters from a combination of its cosmic shear power spectrum, galaxy power spectrum, and cluster mass function measurements. We find that the combination of these three probes vastly improves the survey's potential to measure the time evolution of dark energy. In terms of a dark energy figure-of-merit defined as (?(w{sub p})?(w{sub a})){sup ?1}, we find a value of 690 for Euclid-like data combined with Planck-like measurements of the cosmic microwave background anisotropies in a 10-dimensional cosmological parameter space, assuming a ?CDM fiducial cosmology. For the more commonly used 7-parameter model, we find a figure-of-merit of 1900 for the same data combination. We consider also the survey's potential to measure dark energy perturbations in models wherein the dark energy is parameterised as a fluid with a nonstandard non-adiabatic sound speed, and find that in an optimistic scenario in which w{sub 0} deviates from -1 by as much as is currently observationally allowed, models with c-circumflex {sub s}{sup 2} = 10{sup ?6} and c-circumflex {sub s}{sup 2} = 1 can be distinguished from one another at more than 2? significance. We emphasise that constraints on the dark energy sound speed from cluster measurements are strongly dependent on the modelling of the cluster mass function; significantly weaker sensitivities ensue if we modify our model to include fewer features of nonlinear dark energy clustering. Finally, we find that the sum of neutrino masses can be measured with a 1? precision of 0.015 eV, even in complex cosmological models in which the dark energy equation of state varies with time. The 1? sensitivity to the effective number of relativistic species N{sub eff}{sup ml} is approximately 0.03, meaning that the small deviation of 0.046 from 3 in the standard value of N{sub eff}{sup ml} due to non-instantaneous decoupling and finite temperature effects can be probed with 1? precision for the first time.
O. V. Veko; K. V. Kazmerchuk; E. M. Ovsiyuk; V. V. Kisel; V. M. Red'kov
2014-11-07
Relativistic theory of the Cox's scalar not point-like particle with intrinsic structure is developed on the background of arbitrary curved space-time. It is shown that in the most general form, the extended Proca-like tensor first order system of equations contains non minimal interaction terms through electromagnetic tensor F_{\\alpha \\beta} and Ricci tensor R_{\\alpha \\beta}. In relativistic Cox's theory, the limiting procedure to non-relativistic approximation is performed in a special class of curved space-time models. This theory is specified in simple geometrical backgrounds: Euclid's, Lobachevsky's, and Rie\\-mann's. Wave equation for the Cox's particle is solved exactly in presence of external uniform magnetic and electric fields in the case of Minkowski space. Non-trivial additional structure of the particle modifies the frequency of a quantum oscillator arising effectively in presence if external magnetic field. Extension of these problems to the case of the hyperbolic Lobachevsky space is examined. In presence of the magnetic field, the quantum problem in radial variable has been solved exactly; the quantum motion in z-direction is described by 1-dimensional Schr\\"{o}dinger-like equation in an effective potential which turns out to be too difficult for analytical treatment. In the presence of electric field, the situation is similar. The same analysis has been performed for spherical Riemann space model.
Supermassive population III supernovae and the birth of the first quasars
Whalen, Daniel J.; Smidt, Joseph [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Even, Wesley; Fryer, Chris L. [CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Victoria 3800 (Australia); Chen, K.-J. [School of Physics and Astronomy, University of Minnesota, Twin Cities, Minneapolis, MN 55455 (United States); Stiavelli, Massimo [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Xu, Hao [Center for Astrophysics and Space Sciences, UC San Diego, La Jolla, CA 92093 (United States); Joggerst, Candace C. [XTD-3, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
2013-11-20
The existence of supermassive black holes as early as z ? 7 is one of the great, unsolved problems in cosmological structure formation. One leading theory argues that they are born during catastrophic baryon collapse in z ? 15 protogalaxies that form in strong Lyman-Werner UV backgrounds. Atomic line cooling in such galaxies fragments baryons into massive clumps that are thought to directly collapse to 10{sup 4}-10{sup 5} M {sub ?} black holes. We have now discovered that some of these fragments can instead become supermassive stars that eventually explode as thermonuclear supernovae (SNe) with energies of ?10{sup 55} erg, the most energetic explosions in the universe. We have calculated light curves and spectra for supermassive Pop III SNe with the Los Alamos RAGE and SPECTRUM codes. We find that they will be visible in near-infrared all-sky surveys by Euclid out to z ? 10-15 and by WFIRST and WISH out to z ? 15-20, perhaps revealing the birthplaces of the first quasars.
BIAS-FREE SHEAR ESTIMATION USING ARTIFICIAL NEURAL NETWORKS
Gruen, D.; Seitz, S.; Koppenhoefer, J.; Riffeser, A., E-mail: dgruen@usm.uni-muenchen.d [University Observatory Munich, Scheinerstrasse 1, 81679 Muenchen (Germany)
2010-09-01
Bias due to imperfect shear calibration is the biggest obstacle when constraints on cosmological parameters are to be extracted from large area weak lensing surveys such as Pan-STARRS-3{pi}, DES, or future satellite missions like EUCLID. We demonstrate that bias present in existing shear measurement pipelines (e.g., KSB) can be almost entirely removed by means of neural networks. In this way, bias correction can depend on the properties of the individual galaxy instead of being a single global value. We present a procedure to train neural networks for shear estimation and apply this to subsets of simulated GREAT08 RealNoise data. We also show that circularization of the point-spread function (PSF) before measuring the shear reduces the scatter related to the PSF anisotropy correction and thus leads to improved measurements, particularly on low and medium signal-to-noise data. Our results are competitive with the best performers in the GREAT08 competition, especially for the medium and higher signal-to-noise sets. Expressed in terms of the quality parameter defined by GREAT08, we achieve a Q{approx} 40, 140, and 1300 without and 50, 200, and 1300 with circularization for low, medium, and high signal-to-noise data sets, respectively.
Towards A Census of Earth-mass Exo-planets with Gravitational Microlensing
J. P. Beaulieu; E. Kerins; S. Mao; D. Bennett; A. Cassan; S. Dieters; B. S. Gaudi; A. Gould; V. Batista; R. Bender; S. Brillant; K. Cook; C. Coutures; D. Dominis-Prester; J. Donatowicz; P. Fouqué; E. Grebel; J. Greenhill; D. Heyrovsky; K. Horne; D. Kubas; J. B. Marquette; J. Menzies; N. J. Rattenbury; I. Ribas; K. Sahu; Y. Tsapras; A. Udalski; C. Vinter
2008-07-31
Thirteen exo-planets have been discovered using the gravitational microlensing technique (out of which 7 have been published). These planets already demonstrate that super-Earths (with mass up to ~10 Earth masses) beyond the snow line are common and multiple planet systems are not rare. In this White Paper we introduce the basic concepts of the gravitational microlensing technique, summarise the current mode of discovery and outline future steps towards a complete census of planets including Earth-mass planets. In the near-term (over the next 5 years) we advocate a strategy of automated follow-up with existing and upgraded telescopes which will significantly increase the current planet detection efficiency. In the medium 5-10 year term, we envision an international network of wide-field 2m class telescopes to discover Earth-mass and free-floating exo-planets. In the long (10-15 year) term, we strongly advocate a space microlensing telescope which, when combined with Kepler, will provide a complete census of planets down to Earth mass at almost all separations. Such a survey could be undertaken as a science programme on Euclid, a dark energy probe with a wide-field imager which has been proposed to ESA's Cosmic Vision Programme.
DESI and other Dark Energy experiments in the era of neutrino mass measurements
Font-Ribera, Andreu; McDonald, Patrick; Mostek, Nick; Reid, Beth A.; Seo, Hee-Jong; Slosar, Anže E-mail: PVMcDonald@lbl.gov E-mail: BAReid@lbl.gov E-mail: anze@bnl.gov
2014-05-01
We present Fisher matrix projections for future cosmological parameter measurements, including neutrino masses, Dark Energy, curvature, modified gravity, the inflationary perturbation spectrum, non-Gaussianity, and dark radiation. We focus on DESI and generally redshift surveys (BOSS, HETDEX, eBOSS, Euclid, and WFIRST), but also include CMB (Planck) and weak gravitational lensing (DES and LSST) constraints. The goal is to present a consistent set of projections, for concrete experiments, which are otherwise scattered throughout many papers and proposals. We include neutrino mass as a free parameter in most projections, as it will inevitably be relevant — DESI and other experiments can measure the sum of neutrino masses to ? 0.02 eV or better, while the minimum possible sum is ? 0.06 eV. We note that constraints on Dark Energy are significantly degraded by the presence of neutrino mass uncertainty, especially when using galaxy clustering only as a probe of the BAO distance scale (because this introduces additional uncertainty in the background evolution after the CMB epoch). Using broadband galaxy power becomes relatively more powerful, and bigger gains are achieved by combining lensing survey constraints with redshift survey constraints. We do not try to be especially innovative, e.g., with complex treatments of potential systematic errors — these projections are intended as a straightforward baseline for comparison to more detailed analyses.
Extending cosmological tests of General Relativity with the Square Kilometre Array
Philip Bull
2015-09-24
Tests of general relativity (GR) are still in their infancy on cosmological scales, but forthcoming experiments promise to greatly improve their precision over a wide range of distance scales and redshifts. One such experiment, the Square Kilometre Array (SKA), will carry out several wide and deep surveys of resolved and unresolved neutral hydrogen (HI) 21cm line-emitting galaxies, mapping a significant fraction of the sky from $0 \\le z \\lesssim 6$. I present forecasts for the ability of a suite of possible SKA HI surveys to detect deviations from GR by reconstructing the cosmic expansion and growth history. SKA Phase 1 intensity mapping surveys can achieve sub-1% measurements of $f\\sigma_8$ out to $z\\approx 1$, with an SKA1-MID Band 2 survey out to $z \\lesssim 0.6$ able to surpass contemporary spectroscopic galaxy surveys such as DESI and Euclid in terms of constraints on modified gravity parameters if challenges such as foreground contamination can be tackled effectively. A more futuristic Phase 2 HI survey of $\\sim 10^9$ spectroscopic galaxy redshifts would be capable of detecting a $\\sim 2\\%$ modification of the Poisson equation out to $z\\approx 2$.
Julien Bel; Philippe Brax; Christian Marinoni; Patrick Valageas
2015-04-23
The clustering ratio $\\eta$, a large-scale structure observable originally designed to constrain the shape of the power spectrum of matter density fluctuations, is shown to provide a sensitive probe of the nature of gravity in the cosmological regime. We apply this analysis to $F(R)$ theories of gravity using the luminous red galaxy (LRG) sample extracted from the spectroscopic Sloan Digital Sky Survey (SDSS) data release 7 and 10 catalogues. We find that General Relativity (GR), complemented with a Friedmann-Robertson-Walker (FRW) cosmological model with parameters fixed by the Planck satellite, describes extremely well the clustering of galaxies up to $z\\sim 0.6$. On large cosmic scales, the absolute amplitude of deviations from GR, $|f_{R_0 }|$, is constrained to be smaller than $4.6 \\times 10^{-5}$ at the $95\\%$ confidence level. This bound makes cosmological probes of gravity almost competitive with the sensitivity of Solar System tests, although still one order of magnitude less effective than astrophysical tests. We also extrapolate our results to future large surveys like Euclid and show that the astrophysical bound will certainly remain out of reach for such a class of modified-gravity models that only differ from $\\Lambda$CDM at low redshifts.
The general relativistic instability supernova of a supermassive population III star
Chen, Ke-Jung; Woosley, Stan [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Victoria 3800 (Australia); Almgren, Ann [Center for Computational Sciences and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Whalen, Daniel J. [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Johnson, Jarrett L., E-mail: kchen@ucolick.org [XTD-PRI, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
2014-08-01
The formation of supermassive Population III stars with masses ?10,000 M{sub ?} in primeval galaxies in strong ultraviolet backgrounds at z ? 15 may be the most viable pathway to the formation of supermassive black holes by z ? 7. Most of these stars are expected to live for short times and then directly collapse to black holes, with little or no mass loss over their lives. However, we have now discovered that non-rotating primordial stars with masses close to 55,000 M{sub ?} can instead die as highly energetic thermonuclear supernovae powered by explosive helium burning, releasing up to 10{sup 55} erg, or about 10,000 times the energy of a Type Ia supernova. The explosion is triggered by the general relativistic contribution of thermal photons to gravity in the core of the star, which causes the core to contract and explosively burn. The energy release completely unbinds the star, leaving no compact remnant, and about half of the mass of the star is ejected into the early cosmos in the form of heavy elements. The explosion would be visible in the near infrared at z ? 20 to Euclid and the Wide-Field Infrared Survey Telescope, perhaps signaling the birth of supermassive black hole seeds and the first quasars.
Measuring line-of-sight dependent Fourier-space clustering using FFTs
Bianchi, Davide; Ruggeri, Rossana; Percival, Will J
2015-01-01
Observed galaxy clustering exhibits local transverse statistical isotropy around the line-of-sight (LOS). The variation of the LOS across a galaxy survey complicates the measurement of the observed clustering as a function of the angle to the LOS, as Fast Fourier Transforms (FFTs) based on cartesian grids, cannot individually allow for this. Recent advances in methodology for calculating LOS-dependent clustering in Fourier space include the realisation that power spectrum LOS-dependent moments can be constructed from sums over galaxies, based on approximating the LOS to each pair of galaxies by the LOS to one of them. We show that we can implement this method using multiple FFTs, each measuring the LOS-weighted clustering along different axes. The N log(N) nature of FFTs means that the computational speed-up is a factor of >1000 compared with summing over galaxies. This development should be beneficial for future projects such as DESI and Euclid which will provide an order of magnitude more galaxies than curr...
Extracting the late-time kinetic Sunyaev-Zel'dovich effect
Munshi, D; Dixon, K L; Coles, P
2015-01-01
We propose a novel technique to separate the late-time, post-reionization component of the kinetic Sunyaev-Zeldovich (kSZ) effect from the contribution to it from a (poorly understood and probably patchy) reionization history. The kSZ effect is one of the most promising probe of the {\\em missing baryons} in the Universe. We study the possibility of reconstructing it in three dimensions (3D), using future spectroscopic surveys such as the Euclid survey. By reconstructing a 3D template from galaxy density and peculiar velocity fields from spectroscopic surveys we cross-correlate the estimator against CMB maps. The resulting cross-correlation can help us to map out the kSZ contribution to CMB in 3D as a function of redshift thereby extending previous results which use tomographic reconstruction. This allows the separation of the late time effect from the contribution owing to reionization. By construction, it avoids contamination from foregrounds, primary CMB, tSZ effect as well as from star forming galaxies. Du...
Extending cosmological tests of General Relativity with the Square Kilometre Array
Bull, Philip
2015-01-01
Tests of general relativity (GR) are still in their infancy on cosmological scales, but forthcoming experiments promise to greatly improve their precision over a wide range of distance scales and redshifts. One such experiment, the Square Kilometre Array (SKA), will carry out several wide and deep surveys of resolved and unresolved neutral hydrogen (HI) 21cm line-emitting galaxies, mapping a significant fraction of the sky from $0 \\le z \\lesssim 6$. I present forecasts for the ability of a suite of possible SKA HI surveys to detect deviations from GR by reconstructing the cosmic expansion and growth history. SKA Phase 1 intensity mapping surveys can achieve sub-1% measurements of $f\\sigma_8$ out to $z\\approx 1$, with an SKA1-MID Band 2 survey out to $z \\lesssim 0.6$ able to surpass contemporary spectroscopic galaxy surveys such as DESI and Euclid in terms of constraints on modified gravity parameters if challenges such as foreground contamination can be tackled effectively. A more futuristic Phase 2 HI survey...
The signature of dark energy perturbations in galaxy cluster surveys
Abramo, L.R.; Batista, R.C. [Instituto de Física, Universidade de São Paulo, CP 66318, 05314-970, São Paulo (Brazil); Rosenfeld, R., E-mail: abramo@fma.if.usp.br, E-mail: rbatista@fma.if.usp.br, E-mail: rosenfel@ift.unesp.br [Instituto de Física Teórica, Universidade Estadual Paulista, R. Dr. Bento Teobaldo Ferraz 271, 01140-070, São Paulo (Brazil)
2009-07-01
Models of dynamical dark energy unavoidably possess fluctuations in the energy density and pressure of that new component. In this paper we estimate the impact of dark energy fluctuations on the number of galaxy clusters in the Universe using a generalization of the spherical collapse model and the Press-Schechter formalism. The observations we consider are several hypothetical Sunyaev-Zel'dovich and weak lensing (shear maps) cluster surveys, with limiting masses similar to ongoing (SPT, DES) as well as future (LSST, Euclid) surveys. Our statistical analysis is performed in a 7-dimensional cosmological parameter space using the Fisher matrix method. We find that, in some scenarios, the impact of these fluctuations is large enough that their effect could already be detected by existing instruments such as the South Pole Telescope, when priors from other standard cosmological probes are included. We also show how dark energy fluctuations can be a nuisance for constraining cosmological parameters with cluster counts, and point to a degeneracy between the parameter that describes dark energy pressure on small scales (the effective sound speed) and the parameters describing its equation of state.
Wide Angle Effects in Galaxy Surveys
Yoo, Jaiyul
2013-01-01
Current and future galaxy surveys cover a large fraction of the entire sky with a significant redshift range, and the recent theoretical development shows that general relativistic effects are present in galaxy clustering on very large scales. This trend has renewed interest in the wide angle effect in galaxy clustering measurements, in which the distant-observer approximation is often adopted. Using the full wide-angle formula for computing the redshift-space correlation function, we show that compared to the sample variance, the deviation in the redshift-space correlation function from the simple Kaiser formula with the distant-observer approximation is negligible in the SDSS and is completely irrelevant in future galaxy surveys such as Euclid and the BigBOSS, if the theoretical prediction from the Kaiser formula is averaged over the survey volume and the non-uniform distribution of cosine angle between the line-of-sight and the pair separation directions is properly considered. We also find small correctio...
Eifler, Tim; Krause, Elisabeth; Dodelson, Scott; Zentner, Andrew; Hearin, Andrew; Gnedin, Nickolay
2014-05-28
Systematic uncertainties that have been subdominant in past large-scale structure (LSS) surveys are likely to exceed statistical uncertainties of current and future LSS data sets, potentially limiting the extraction of cosmological information. Here we present a general framework (PCA marginalization) to consistently incorporate systematic effects into a likelihood analysis. This technique naturally accounts for degeneracies between nuisance parameters and can substantially reduce the dimension of the parameter space that needs to be sampled. As a practical application, we apply PCA marginalization to account for baryonic physics as an uncertainty in cosmic shear tomography. Specifically, we use CosmoLike to run simulated likelihood analyses on three independent sets of numerical simulations, each covering a wide range of baryonic scenarios differing in cooling, star formation, and feedback mechanisms. We simulate a Stage III (Dark Energy Survey) and Stage IV (Large Synoptic Survey Telescope/Euclid) survey and find a substantial bias in cosmological constraints if baryonic physics is not accounted for. We then show that PCA marginalization (employing at most 3 to 4 nuisance parameters) removes this bias. Our study demonstrates that it is possible to obtain robust, precise constraints on the dark energy equation of state even in the presence of large levels of systematic uncertainty in astrophysical processes. We conclude that the PCA marginalization technique is a powerful, general tool for addressing many of the challenges facing the precision cosmology program.
CosmoDM and its application to Pan-STARRS data
Desai, S; Henderson, R; Kummel, M; Paech, K; Wetzstein, M
2015-01-01
The Cosmology Data Management system (CosmoDM) is an automated and flexible data management system for the processing and calibration of data from optical photometric surveys. It is designed to run on supercomputers and to minimize disk I/O to enable scaling to very high throughput during periods of reprocessing. It serves as an early prototype for one element of the ground-based processing required by the Euclid mission and will also be employed in the preparation of ground based data needed in the eROSITA X-ray all sky survey mission. CosmoDM consists of two main pipelines. The first is the single-epoch or detrending pipeline, which is used to carry out the photometric and astrometric calibration of raw exposures. The second is the co- addition pipeline, which combines the data from individual exposures into deeper coadd images and science ready catalogs. A novel feature of CosmoDM is that it uses a modified stack of As- tromatic software which can read and write tile compressed images. Since 2011, CosmoDM ...
Volumetric (CUBIC) Octonion Sigma-Matrices and their Properties
Sergei Yakimenko
2011-06-02
This work rests upon the certainty that only fields of real and complex numbers, quaternions and octonions have algebras of all four arithmetical operations. Also quaternions are good to represent 3-dimensional Euclid space and 4-dimensional Minkowski space. Moreover algebra of Pauli classical sigma-matrices isomorphic to a split quaternion algebra. In this article author supposes that the hyperspace can be described with octonions and if 4-dimensional Minkowski space is a projection of the hyperspace, consequently equations for 4-dimensional space must be projections of hyperspace equations. Therefore he obtains a new object as volumetric analog of Pauli sigma-matrices for 8 (or maybe 24)-dimensional hyperspace. Also the author represents general form of a volumetric Dirac equation solution. As is well known nonassociativity is the main distinctive feature of octonions. But square matrices cannot be nonassociative. Therefore the author had to introduce cubic sigma-matrices. From another hand a volumetric object has 3 indices, as a result of it one cannot introduce multiplicative operator for cubic matrices, their projections only can be objects of the multiplicative operator. Meanwhile an uncertainty appears because of a rest index. To overcome the uncertainty one need to consider all the 3 projections of an octonion equation.
Linear Perturbation constraints on Multi-coupled Dark Energy
Arpine Piloyan; Valerio Marra; Marco Baldi; Luca Amendola
2014-01-12
The Multi-coupled Dark Energy (McDE) scenario has been recently proposed as a specific example of a cosmological model characterized by a non-standard physics of the dark sector of the universe that nevertheless gives an expansion history which does not significantly differ from the one of the standard $\\Lambda $CDM model. In this work, we present the first constraints on the McDE scenario obtained by comparing the predicted evolution of linear density perturbations with a large compilation of recent data sets for the growth rate $f\\sigma_{8}$, including 6dFGS, LRG, BOSS, WiggleZ and VIPERS. Confirming qualitative expectations, growth rate data provide much tighter bounds on the model parameters as compared to the extremely loose bounds that can be obtained when only the background expansion history is considered. In particular, the $95\\%$ confidence level on the coupling strength $|\\beta |$ is reduced from $|\\beta |\\leq 83$ (background constraints only) to $|\\beta |\\leq 0.88$ (background and linear perturbation constraints). We also investigate how these constraints further improve when using data from future wide-field surveys such as supernova data from LSST and growth rate data from Euclid-type missions. In this case the $95\\%$ confidence level on the coupling further reduce to $|\\beta |\\leq 0.85$. Such constraints are in any case still consistent with a scalar fifth-force of gravitational strength, and we foresee that tighter bounds might be possibly obtained from the investigation of nonlinear structure formation in McDE cosmologies.[Abridged
Integral points on rational curves of the form y=(x^2+bx+c)/(x+a); a,b,c integers
Konstantine Zelator
2013-01-02
The subject matter of this work is the set of integral points(i.e. points with both coordinates integers) on the graphs of rational functions of the form f(x)=(x^2+bx+c)/(x+a), with a,b,c,being integers.Following the introduction, we establish Proposition1 in Section2. This proposition plays a key role in the proof of Theorem1 in Section5. Proposition1 is proved with the aid of Euclid's lemma and another well known result in number theory; see reference [1].In Sections3 and4, we focus on the special case b^2-4c=0; which implies b=2d and c=d^2, for some integer d. If d and a are distinct; then there are finitely many integral points, parametrically described in Results1 and2. Theorem1 in Sec.5 deals with the general case.Accordingly, if a^2-ab+c is not zero; there are exactly 4N distinct integral points parametrically described.Except in the cases where a^2-ab+c is a perfect square, or minus a perfect square; in which cases thare are exactly 4N-2 distinct integral points. Here N stands for the number of positive divisors, not exceeding the square root of the absolute value of a^2-ab+c. (divisors of that absolute value).The paper concludes with Th.2, which is a direct application of Th.1 in the cases where the above absolute value is 1, p, or p^2; p a prime.
The focal plane instrumentation for the DUNE mission
Jeff Booth; Mark Cropper; Frank Eisenhauer; Alexandre Refregier; the DUNE collaboration
2008-07-25
DUNE (Dark Universe Explorer) is a proposed mission to measure parameters of dark energy using weak gravitational lensing The particular challenges of both optical and infrared focal planes and the DUNE baseline solution is discussed. The DUNE visible Focal Plane Array (VFP) consists of 36 large format red-sensitive CCDs, arranged in a 9x4 array together with the associated mechanical support structure and electronics processing chains. Four additional CCDs dedicated to attitude control measurements are located at the edge of the array. All CCDs are 4096 pixel red-enhanced e2v CCD203-82 devices with square 12 $\\mu$m pixels, operating from 550-920nm. Combining four rows of CCDs provides a total exposure time of 1500s. The VFP will be used in a closed-loop system by the spacecraft, which operates in a drift scan mode, in order to synchronize the scan and readout rates. The Near Infrared (NIR) FPA consists of a 5 x 12 mosaic of 60 Hawaii 2RG detector arrays from Teledyne, NIR bandpass filters for the wavelength bands Y, J, and H, the mechanical support structure, and the detector readout and signal processing electronics. The FPA is operated at a maximum temperature of 140 K for low dark current of 0.02e$-$/s. Each sensor chip assembly has 2048 x 2048 square pixels of 18 $\\mu$m size (0.15 arcsec), sensitive in the 0.8 to 1.7 $\\mu$m wavelength range. As the spacecraft is scanning the sky, the image motion on the NIR FPA is stabilized by a de-scanning mirror during the integration time of 300 s per detector. The total integration time of 1500 seconds is split among the three NIR wavelengths bands. DUNE has been proposed to ESA's Cosmic Vision program and has been jointly selected with SPACE for an ESA Assessment Phase which has led to the joint Euclid mission concept.
CLUSTER LENSING PROFILES DERIVED FROM A REDSHIFT ENHANCEMENT OF MAGNIFIED BOSS-SURVEY GALAXIES
Coupon, Jean; Umetsu, Keiichi [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Broadhurst, Tom, E-mail: coupon@asiaa.sinica.edu.tw [Department of Theoretical Physics, University of Basque Country UPV/EHU, P.O. Box 644, E-48080 Bilbao (Spain)
2013-07-20
We report the first detection of a redshift-depth enhancement of background galaxies magnified by foreground clusters. Using 300,000 BOSS survey galaxies with accurate spectroscopic redshifts, we measure their mean redshift depth behind four large samples of optically selected clusters from the Sloan Digital Sky Survey (SDSS) surveys, totaling 5000-15,000 clusters. A clear trend of increasing mean redshift toward the cluster centers is found, averaged over each of the four cluster samples. In addition, we find similar but noisier behavior for an independent X-ray sample of 158 clusters lying in the foreground of the current BOSS sky area. By adopting the mass-richness relationships appropriate for each survey, we compare our results with theoretical predictions for each of the four SDSS cluster catalogs. The radial form of this redshift enhancement is well fitted by a richness-to-mass weighted composite Navarro-Frenk-White profile with an effective mass ranging between M{sub 200} {approx} 1.4-1.8 Multiplication-Sign 10{sup 14} M{sub Sun} for the optically detected cluster samples, and M{sub 200} {approx} 5.0 Multiplication-Sign 10{sup 14} M{sub Sun} for the X-ray sample. This lensing detection helps to establish the credibility of these SDSS cluster surveys, and provides a normalization for their respective mass-richness relations. In the context of the upcoming bigBOSS, Subaru Prime Focus Spectrograph, and EUCLID-NISP spectroscopic surveys, this method represents an independent means of deriving the masses of cluster samples for examining the cosmological evolution, and provides a relatively clean consistency check of weak-lensing measurements, free from the systematic limitations of shear calibration.
Laura Taddei; Luca Amendola
2014-08-15
Most cosmological constraints on modified gravity are obtained assuming that the cosmic evolution was standard $\\Lambda$CDM in the past and that the present matter density and power spectrum normalization are the same as in a $\\Lambda$CDM model. Here we examine how the constraints change when these assumptions are lifted. We focus in particular on the parameter $Y$ (also called $G_{\\mathrm{eff}}$) that quantifies the deviation from the Poisson equation. This parameter can be estimated by comparing with the model-independent growth rate quantity $f\\sigma_{8}(z)$ obtained through redshift distortions. We reduce the model dependency in evaluating $Y$ by marginalizing over $\\sigma_{8}$ and over the initial conditions, and by absorbing the degenerate parameter $\\Omega_{m,0}$ into $Y$. We use all currently available values of $f\\sigma_{8}(z)$. We find that the combination $\\hat{Y}=Y\\Omega_{m,0}$, assumed constant in the observed redshift range, can be constrained only very weakly by current data, $\\hat{Y}=0.28_{-0.23}^{+0.35}$ at 68\\% c.l. We also forecast the precision of a future estimation of $\\hat{Y}$ in a Euclid-like redshift survey. We find that the future constraints will reduce substantially the uncertainty, $\\hat{Y}=0.30_{-0.09}^{+0.08}$ , at 68\\% c.l., but the relative error on $\\hat{Y}$ around the fiducial remains quite high, of the order of 30\\%. The main reason for these weak constraints is that $\\hat{Y}$ is strongly degenerate with the initial conditions, so that large or small values of $\\hat{Y}$ are compensated by choosing non-standard initial values of the derivative of the matter density contrast. Finally, we produce a forecast of a cosmological exclusion plot on the Yukawa strength and range parameters, which complements similar plots on laboratory scales but explores scales and epochs reachable only with large-scale galaxy surveys. (abridged)
Measuring primordial non-Gaussianity with weak-lensing surveys
Stefan Hilbert; Laura Marian; Robert E. Smith; Vincent Desjacques
2012-11-02
We study the ability of future weak lensing (WL) surveys to constrain primordial non-Gaussianity of the local type. We use a large ensemble of simulated WL maps with survey specifications relevant to Euclid and LSST. The simulations assume Cold Dark Matter cosmologies that vary certain parameters around fiducial values: the non-Gaussianity parameter f_NL, the matter density parameter Omega_m, the amplitude of the matter power spectrum sigma_8, the spectral index of the primordial power spectrum n_s, and the dark-energy equation-of-state parameter w_0. We assess the sensitivity of the cosmic shear correlation functions, the third-order aperture mass statistics, and the abundance of shear peaks to these parameters. We find that each of the considered probes provides unmarginalized constraints of Delta f_NL ~ 20 on f_NL. Marginalized constraints from any individual WL probe are much weaker due to strong correlations between parameters. However, the parameter errors can be substantially reduced by combining information from different WL probes. Combining all WL probes yields the following marginal (68% confidence level) uncertainties: Delta f_NL ~ 50, Delta Omega_m ~ 0.002, Delta sigma_8 ~ 0.004, Delta n_s ~ 0.007, and Delta w_0 ~ 0.03. We examine the bias induced by neglecting f_NL on the constraints on the other parameters. We find sigma_8 and w_0 to be the most affected. Moreover, neglecting non-Gaussianity leads to a severe underestimation of the uncertainties in the other cosmological parameters.
Probing non-standard gravity with the growth index: a background independent analysis
Steigerwald, Heinrich; Marinoni, Christian; Bel, Julien E-mail: jbel@cpt.univ-mrs.fr
2014-05-01
Measurements of the growth index of linear matter density fluctuations ?(z) provide a clue as to whether Einstein's field equations encompass gravity also on large cosmic scales, those where the expansion of the universe accelerates. We show that the information encoded in this function can be satisfactorily parameterized using a small set of coefficients ?{sub i}, in such a way that the true scaling of the growth index is recovered to better than 1% in most dark energy and dark gravity models. We find that the likelihood of current data, given this formalism and the ? Cold Dark Matter (?CDM) expansion model of Planck, is maximal for ?{sub 0} = 0.74{sup +0.44}{sub ?0.41} and ?{sub 1} = 0.01{sup +0.46}{sub ?0.46}, a measurement compatible with the ?CDM predictions (?{sub 0} = 0.545, ?{sub 1} = ?0.007). In addition, data tend to favor models predicting slightly less growth of structures than the Planck ?CDM scenario. The main aim of the paper is to provide a prescription for routinely calculating, in an analytic way, the amplitude of the growth indices ?{sub i} in relevant cosmological scenarios, and to show that these parameters naturally define a space where predictions of alternative theories of gravity can be compared against growth data in a manner which is independent from the expansion history of the cosmological background. As the standard ?-plane provides a tool to identify different expansion histories H(t) and their relation to various cosmological models, the ?-plane can thus be used to locate different growth rate histories f(t) and their relation to alternatives model of gravity. As a result, we find that the Dvali-Gabadadze-Porrati gravity model is rejected with a 95% confidence level. By simulating future data sets, such as those that a Euclid-like mission will provide, we also show how to tell apart ?CDM predictions from those of more extreme possibilities, such as smooth dark energy models, clustering quintessence or parameterized post-Friedmann cosmological models.
The Rational Number n/p as a sum of two unit fractions
Konstantine Zelator
2012-02-29
In a 2011 paper published in the journal "Asian Journal of Algebra"(see reference[1]), the authors consider, among other equations,the diophantine equations 2xy=n(x+y) and 3xy=n(x+y). For the first equation, with n being an odd positive integer, they give the solution x=(n+1)/2, y=n(n+1)/2. For the second equation they present the particular solution, x=(n+1)/3,y=n(n+1)/3, where is n is a positive integer congruent to 2modulo3. If in the above equations we assume n to be prime, then these two equations become special cases of the diophantine equation, nxy=p(x+y) (1), with p being a prime and n a positive integer greater than or equal to 2. This 2-variable symmetric diophantine equation is the subject matter of this article; with the added condition that the intager n is not divisible by the prime p. Observe that this equation can be written in fraction form: n/p= 1/x + 1/y(See [2] for more details) In this work we prove the following result, Theorem1(stated on page2 of this paper):Let p be a prime, n a positive integer at least2, and not divisible by p. Then, 1)If n=2 and p is an odd prime, equation (1) has exactly three distinct positive integer solutions:x=p, y=p ; x=p(p+1)/2, y=(p+1)/2 ; x=(p+1)/2, y=p(p+1)/2 2)If n is greater than or equal to 3, and n is a divisor of p+1. Then equation (1) has exactly two distinct solutions: x=p(p+1)/n, y=(p+1)/n ; x=(p+1)/n, y=p(p+1)/n 3) if n is not a divisor of p+1. Then equation (1) has no positive integer solution. The proof of this result is elementary, and only uses Euclid's Lemma from number theory,and basic divisor arguments(such that if a prime divides a product of two integers; it must divide at least one of them).
RECONSTRUCTING REDSHIFT DISTRIBUTIONS WITH CROSS-CORRELATIONS: TESTS AND AN OPTIMIZED RECIPE
Matthews, Daniel J.; Newman, Jeffrey A., E-mail: djm70@pitt.ed, E-mail: janewman@pitt.ed [Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, PA 15260 (United States)
2010-09-20
Many of the cosmological tests to be performed by planned dark energy experiments will require extremely well-characterized photometric redshift measurements. Current estimates for cosmic shear are that the true mean redshift of the objects in each photo-z bin must be known to better than 0.002(1 + z), and the width of the bin must be known to {approx}0.003(1 + z) if errors in cosmological measurements are not to be degraded significantly. A conventional approach is to calibrate these photometric redshifts with large sets of spectroscopic redshifts. However, at the depths probed by Stage III surveys (such as DES), let alone Stage IV (LSST, JDEM, and Euclid), existing large redshift samples have all been highly (25%-60%) incomplete, with a strong dependence of success rate on both redshift and galaxy properties. A powerful alternative approach is to exploit the clustering of galaxies to perform photometric redshift calibrations. Measuring the two-point angular cross-correlation between objects in some photometric redshift bin and objects with known spectroscopic redshift, as a function of the spectroscopic z, allows the true redshift distribution of a photometric sample to be reconstructed in detail, even if it includes objects too faint for spectroscopy or if spectroscopic samples are highly incomplete. We test this technique using mock DEEP2 Galaxy Redshift survey light cones constructed from the Millennium Simulation semi-analytic galaxy catalogs. From this realistic test, which incorporates the effects of galaxy bias evolution and cosmic variance, we find that the true redshift distribution of a photometric sample can, in fact, be determined accurately with cross-correlation techniques. We also compare the empirical error in the reconstruction of redshift distributions to previous analytic predictions, finding that additional components must be included in error budgets to match the simulation results. This extra error contribution is small for surveys that sample large areas of sky (>{approx}10{sup 0}-100{sup 0}), but dominant for {approx}1 deg{sup 2} fields. We conclude by presenting a step-by-step, optimized recipe for reconstructing redshift distributions from cross-correlation information using standard correlation measurements.