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Title: Five years of searches for point sources of astrophysical neutrinos with the AMANDA-II neutrino telescope

Abstract

We report the results of a five-year survey of the northern sky to search for point sources of high energy neutrinos. The search was performed on the data collected with the AMANDA-II neutrino telescope in the years 2000 to 2004, with a live time of 1001 days. The sample of selected events consists of 4282 upward going muon tracks with high reconstruction quality and an energy larger than about 100 GeV. We found no indication of point sources of neutrinos and set 90% confidence level flux upper limits for an all-sky search and also for a catalog of 32 selected sources. For the all-sky search, our average (over declination and right ascension) experimentally observed upper limit {phi}{sup 0}=((E/1 TeV)){sup {gamma}}{center_dot}(d{phi}/dE) to a point source flux of muon and tau neutrino (detected as muons arising from taus) is {phi}{sub {nu}{sub {mu}}+{nu}{sub {mu}}{sup 0}}+{phi}{sub {nu}{sub {tau}}+{nu}{sub {tau}}}{sup 0}=11.1x 10{sup -11} TeV{sup -1} cm{sup -2} s{sup -1}, in the energy range between 1.6 TeV and 2.5 PeV for a flavor ratio {phi}{sub {nu}{sub {mu}}+{nu}{sub {mu}}{sup 0}}/{phi}{sub {nu}{sub {tau}}+{nu}{sub {tau}}}{sup 0}=1 and assuming a spectral index {gamma}=2. It should be noticed that this is the first time we set upper limits to the fluxmore » of muon and tau neutrinos. In previous papers we provided muon neutrino upper limits only neglecting the sensitivity to a signal from tau neutrinos, which improves the limits by 10% to 16%. The value of the average upper limit presented in this work corresponds to twice the limit on the muon neutrino flux {phi}{sub {nu}{sub {mu}}+{nu}{sub {mu}}}{sup 0}=5.5x10{sup -11} TeV{sup -1} cm{sup -2} s{sup -1}. A stacking analysis for preselected active galactic nuclei and a search based on the angular separation of the events were also performed. We report the most stringent flux upper limits to date, including the results of a detailed assessment of systematic uncertainties.« less

Authors:
; ; ;  [1]; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;  [2]
  1. Department of Physics and Astronomy, Utrecht University/SRON, NL-3584 CC Utrecht (Netherlands)
  2. DESY, D-15735 Zeuthen (Germany) (and others)
Publication Date:
OSTI Identifier:
20933284
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 10; Other Information: DOI: 10.1103/PhysRevD.75.102001; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; DEAD TIME; FLAVOR MODEL; GEV RANGE 100-1000; MUON NEUTRINOS; MUONS; PARTICLE TRACKS; PEV RANGE; POINT SOURCES; TAU NEUTRINOS; TELESCOPES; TEV RANGE

Citation Formats

Achterberg, A., Duvoort, M. R., Heise, J., Eijndhoven, N. van, Ackermann, M., Bernardini, E., Bolmont, J., Boeser, S., Klepser, S., Leich, H., Nahnhauer, R., Pieloth, D., Schlenstedt, S., Spiering, C., Steffen, P., Sulanke, K.-H., Tarasova, O., Tluczykont, M., Voigt, B., and Waldmann, H.. Five years of searches for point sources of astrophysical neutrinos with the AMANDA-II neutrino telescope. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.102001.
Achterberg, A., Duvoort, M. R., Heise, J., Eijndhoven, N. van, Ackermann, M., Bernardini, E., Bolmont, J., Boeser, S., Klepser, S., Leich, H., Nahnhauer, R., Pieloth, D., Schlenstedt, S., Spiering, C., Steffen, P., Sulanke, K.-H., Tarasova, O., Tluczykont, M., Voigt, B., & Waldmann, H.. Five years of searches for point sources of astrophysical neutrinos with the AMANDA-II neutrino telescope. United States. doi:10.1103/PHYSREVD.75.102001.
Achterberg, A., Duvoort, M. R., Heise, J., Eijndhoven, N. van, Ackermann, M., Bernardini, E., Bolmont, J., Boeser, S., Klepser, S., Leich, H., Nahnhauer, R., Pieloth, D., Schlenstedt, S., Spiering, C., Steffen, P., Sulanke, K.-H., Tarasova, O., Tluczykont, M., Voigt, B., and Waldmann, H.. Tue . "Five years of searches for point sources of astrophysical neutrinos with the AMANDA-II neutrino telescope". United States. doi:10.1103/PHYSREVD.75.102001.
@article{osti_20933284,
title = {Five years of searches for point sources of astrophysical neutrinos with the AMANDA-II neutrino telescope},
author = {Achterberg, A. and Duvoort, M. R. and Heise, J. and Eijndhoven, N. van and Ackermann, M. and Bernardini, E. and Bolmont, J. and Boeser, S. and Klepser, S. and Leich, H. and Nahnhauer, R. and Pieloth, D. and Schlenstedt, S. and Spiering, C. and Steffen, P. and Sulanke, K.-H. and Tarasova, O. and Tluczykont, M. and Voigt, B. and Waldmann, H.},
abstractNote = {We report the results of a five-year survey of the northern sky to search for point sources of high energy neutrinos. The search was performed on the data collected with the AMANDA-II neutrino telescope in the years 2000 to 2004, with a live time of 1001 days. The sample of selected events consists of 4282 upward going muon tracks with high reconstruction quality and an energy larger than about 100 GeV. We found no indication of point sources of neutrinos and set 90% confidence level flux upper limits for an all-sky search and also for a catalog of 32 selected sources. For the all-sky search, our average (over declination and right ascension) experimentally observed upper limit {phi}{sup 0}=((E/1 TeV)){sup {gamma}}{center_dot}(d{phi}/dE) to a point source flux of muon and tau neutrino (detected as muons arising from taus) is {phi}{sub {nu}{sub {mu}}+{nu}{sub {mu}}{sup 0}}+{phi}{sub {nu}{sub {tau}}+{nu}{sub {tau}}}{sup 0}=11.1x 10{sup -11} TeV{sup -1} cm{sup -2} s{sup -1}, in the energy range between 1.6 TeV and 2.5 PeV for a flavor ratio {phi}{sub {nu}{sub {mu}}+{nu}{sub {mu}}{sup 0}}/{phi}{sub {nu}{sub {tau}}+{nu}{sub {tau}}}{sup 0}=1 and assuming a spectral index {gamma}=2. It should be noticed that this is the first time we set upper limits to the flux of muon and tau neutrinos. In previous papers we provided muon neutrino upper limits only neglecting the sensitivity to a signal from tau neutrinos, which improves the limits by 10% to 16%. The value of the average upper limit presented in this work corresponds to twice the limit on the muon neutrino flux {phi}{sub {nu}{sub {mu}}+{nu}{sub {mu}}}{sup 0}=5.5x10{sup -11} TeV{sup -1} cm{sup -2} s{sup -1}. A stacking analysis for preselected active galactic nuclei and a search based on the angular separation of the events were also performed. We report the most stringent flux upper limits to date, including the results of a detailed assessment of systematic uncertainties.},
doi = {10.1103/PHYSREVD.75.102001},
journal = {Physical Review. D, Particles Fields},
number = 10,
volume = 75,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • No abstract prepared.
  • We present a search for point sources of high energy neutrinos using 3.8 years of data recorded by AMANDA-II during 2000-2006. After reconstructing muon tracks and applying selection criteria designed to optimally retain neutrino-induced events originating in the Northern Sky, we arrive at a sample of 6595 candidate events, predominantly from atmospheric neutrinos with primary energy 100 GeV to 8 TeV. Our search of this sample reveals no indications of a neutrino point source. We place the most stringent limits to date on E{sup -2} neutrino fluxes from points in the Northern Sky, with an average upper limit of E{supmore » 2}{Phi}{sub {nu}{sub {mu}}+{nu}{sub {tau}}} {le} 5.2 x 10{sup -11} TeV cm{sup -2} s{sup -1} on the sum of {nu}{sub {mu}} and {nu}{sub {tau}} fluxes, assumed equal, over the energy range from 1.9 TeV to 2.5 PeV.« less
  • The results of a search for point sources of high energy neutrinos in the northern hemisphere using data collected by AMANDA-II in the years 2000, 2001, and 2002 are presented. In particular, a comparison with the single-year result previously published shows that the sensitivity was improved by a factor of 2.2. The muon neutrino flux upper limits on selected candidate sources, corresponding to an E{sub {nu}}{sup -2} neutrino energy spectrum, are included. Sky grids were used to search for possible excesses above the background of cosmic ray induced atmospheric neutrinos. This search reveals no statistically significant excess for the threemore » years considered.« less
  • We present a search for point sources of high energy neutrinos using 3.8 yr of data recorded by AMANDA-II during 2000-2006. After reconstructing muon tracks and applying selection criteria designed to optimally retain neutrino-induced events originating in the northern sky, we arrive at a sample of 6595 candidate events, predominantly from atmospheric neutrinos with primary energy 100 GeV to 8 TeV. Our search of this sample reveals no indications of a neutrino point source. We place the most stringent limits to date on E{sup -2} neutrino fluxes from points in the northern sky, with an average upper limit of E{supmore » 2}{phi}{sub {nu}{sub {mu}}}{sub +{nu}{sub {tau}}}{<=}5.2x10{sup -11} TeV cm{sup -2} s{sup -1} on the sum of {nu}{sub {mu}} and {nu}{sub {tau}} fluxes, assumed equal, over the energy range from 1.9 TeV to 2.5 PeV.« less
  • A search for cosmic neutrino sources using six years of data collected by the ANTARES neutrino telescope has been performed. Clusters of muon neutrinos over the expected atmospheric background have been looked for. No clear signal has been found. The most signal-like accumulation of events is located at equatorial coordinates R.A. = –46.°8 and decl. = –64.°9 and corresponds to a 2.2σ background fluctuation. In addition, upper limits on the flux normalization of an E {sup –2} muon neutrino energy spectrum have been set for 50 pre-selected astrophysical objects. Finally, motivated by an accumulation of seven events relatively close tomore » the Galactic Center in the recently reported neutrino sample of the IceCube telescope, a search for point sources in a broad region around this accumulation has been carried out. No indication of a neutrino signal has been found in the ANTARES data and upper limits on the flux normalization of an E {sup –2} energy spectrum of neutrinos from point sources in that region have been set. The 90% confidence level upper limits on the muon neutrino flux normalization vary between 3.5 and 5.1 × 10{sup –8} GeV cm{sup –2} s{sup –1}, depending on the exact location of the source.« less