TIME-INTEGRATED SEARCHES FOR POINT-LIKE SOURCES OF NEUTRINOS WITH THE 40-STRING IceCube DETECTOR
- Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)
- Department of Subatomic and Radiation Physics, University of Gent, B-9000 Gent (Belgium)
- Department of Physics, University of Wisconsin, River Falls, WI 54022 (United States)
- Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch (New Zealand)
- Department of Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom)
- Department of Physics, University of Wuppertal, D-42119 Wuppertal (Germany)
- Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)
- Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)
- Department of Physics, University of California, Berkeley, CA 94720 (United States)
- DESY, D-15735 Zeuthen (Germany)
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)
- Department of Physics and Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States)
- Universite Libre de Bruxelles, Science Faculty CP230, B-1050 Brussels (Belgium)
- Fakultaet fuer Physik and Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)
We present the results of time-integrated searches for astrophysical neutrino sources in both the northern and southern skies. Data were collected using the partially completed IceCube detector in the 40-string configuration recorded between 2008 April 5 and 2009 May 20, totaling 375.5 days livetime. An unbinned maximum likelihood ratio method is used to search for astrophysical signals. The data sample contains 36,900 events: 14,121 from the northern sky, mostly muons induced by atmospheric neutrinos, and 22,779 from the southern sky, mostly high-energy atmospheric muons. The analysis includes searches for individual point sources and stacked searches for sources in a common class, sometimes including a spatial extent. While this analysis is sensitive to TeV-PeV energy neutrinos in the northern sky, it is primarily sensitive to neutrinos with energy greater than about 1 PeV in the southern sky. No evidence for a signal is found in any of the searches. Limits are set for neutrino fluxes from astrophysical sources over the entire sky and compared to predictions. The sensitivity is at least a factor of two better than previous searches (depending on declination), with 90% confidence level muon neutrino flux upper limits being between E {sup 2} d{Phi}/dE {approx} 2-200 x 10{sup -12} TeV cm{sup -2} s{sup -1} in the northern sky and between 3-700 x 10{sup -12} TeV cm{sup -2} s{sup -1} in the southern sky. The stacked source searches provide the best limits to specific source classes. The full IceCube detector is expected to improve the sensitivity to d{Phi}/dE{proportional_to}E {sup -2} sources by another factor of two in the first year of operation.
- OSTI ID:
- 21574664
- Journal Information:
- Astrophysical Journal, Vol. 732, Issue 1; Other Information: DOI: 10.1088/0004-637X/732/1/18; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COSMIC NEUTRINOS
MUON NEUTRINOS
NEUTRINO DETECTION
POINT SOURCES
SENSITIVITY
COSMIC RADIATION
DETECTION
ELEMENTARY PARTICLES
FERMIONS
IONIZING RADIATIONS
LEPTONS
MASSLESS PARTICLES
NEUTRINOS
RADIATION DETECTION
RADIATION SOURCES
RADIATIONS