skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Search for time-independent neutrino emission from astrophysical sources with 3 yr of IceCube data

Abstract

We present the results of a search for neutrino point sources using the IceCube data collected between 2008 April and 2011 May with three partially completed configurations of the detector: the 40-, 59-, and 79-string configurations. The live-time of this data set is 1040 days. An unbinned maximum likelihood ratio test was used to search for an excess of neutrinos above the atmospheric background at any given direction in the sky. By adding two more years of data with improved event selection and reconstruction techniques, the sensitivity was improved by a factor of 3.5 or more with respect to the previously published results obtained with the 40-string configuration of IceCube. We performed an all-sky survey and a dedicated search using a catalog of a priori selected objects observed by other telescopes. In both searches, the data are compatible with the background-only hypothesis. In the absence of evidence for a signal, we set upper limits on the flux of muon neutrinos. For an E {sup –2} neutrino spectrum, the observed limits are (0.9-5) × 10{sup –12} TeV{sup –1} cm{sup –2} s{sup –1} for energies between 1 TeV and 1 PeV in the northern sky and (0.9-23.2) × 10{sup –12} TeV{sup –1}more » cm{sup –2} s{sup –1} for energies between 10{sup 2} TeV and 10{sup 2} PeV in the southern sky. We also report upper limits for neutrino emission from groups of sources that were selected according to theoretical models or observational parameters and analyzed with a stacking approach. Some of the limits presented already reach the level necessary to quantitatively test current models of neutrino emission.« less

Authors:
 [1]; ; ; ; ;  [2];  [3]; ;  [4];  [5];  [6];  [7];  [8];  [9];  [10];  [11];  [12];  [13];  [14];  [15] more »; « less
  1. School of Chemistry and Physics, University of Adelaide, Adelaide SA 5005 (Australia)
  2. Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI 53706 (United States)
  3. Department of Physics and Astronomy, University of Gent, B-9000 Gent (Belgium)
  4. DESY, D-15735 Zeuthen (Germany)
  5. Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch (New Zealand)
  6. Département de physique nucléaire et corpusculaire, Université de Genève, CH-1211 Genève (Switzerland)
  7. Institut für Physik, Humboldt-Universität zu Berlin, D-12489 Berlin (Germany)
  8. Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)
  9. Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)
  10. Institute of Physics, University of Mainz, Staudinger Weg 7, D-55099 Mainz (Germany)
  11. Department of Physics, University of California, Berkeley, CA 94720 (United States)
  12. Department of Physics and Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States)
  13. Université Libre de Bruxelles, Science Faculty CP230, B-1050 Brussels (Belgium)
  14. Fakultät für Physik and Astronomie, Ruhr-Universität Bochum, D-44780 Bochum (Germany)
  15. Department of Physics, University of Wuppertal, D-42119 Wuppertal (Germany)
Publication Date:
OSTI Identifier:
22348409
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 779; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; CATALOGS; CONFIGURATION; COSMIC RADIATION; DEAD TIME; EMISSION; MAXIMUM-LIKELIHOOD FIT; MUON NEUTRINOS; PEV RANGE; POINT SOURCES; SENSITIVITY; SPECTRA; TELESCOPES; TEV RANGE

Citation Formats

Aartsen, M. G., Abbasi, R., Ahlers, M., Auffenberg, J., Baker, M., BenZvi, S., Abdou, Y., Ackermann, M., Benabderrahmane, M. L., Adams, J., Aguilar, J. A., Altmann, D., Bai, X., Barwick, S. W., Baum, V., Bay, R., Beatty, J. J., Bechet, S., Tjus, J. Becker, Becker, K.-H., and and others. Search for time-independent neutrino emission from astrophysical sources with 3 yr of IceCube data. United States: N. p., 2013. Web. doi:10.1088/0004-637X/779/2/132.
Aartsen, M. G., Abbasi, R., Ahlers, M., Auffenberg, J., Baker, M., BenZvi, S., Abdou, Y., Ackermann, M., Benabderrahmane, M. L., Adams, J., Aguilar, J. A., Altmann, D., Bai, X., Barwick, S. W., Baum, V., Bay, R., Beatty, J. J., Bechet, S., Tjus, J. Becker, Becker, K.-H., & and others. Search for time-independent neutrino emission from astrophysical sources with 3 yr of IceCube data. United States. doi:10.1088/0004-637X/779/2/132.
Aartsen, M. G., Abbasi, R., Ahlers, M., Auffenberg, J., Baker, M., BenZvi, S., Abdou, Y., Ackermann, M., Benabderrahmane, M. L., Adams, J., Aguilar, J. A., Altmann, D., Bai, X., Barwick, S. W., Baum, V., Bay, R., Beatty, J. J., Bechet, S., Tjus, J. Becker, Becker, K.-H., and and others. Fri . "Search for time-independent neutrino emission from astrophysical sources with 3 yr of IceCube data". United States. doi:10.1088/0004-637X/779/2/132.
@article{osti_22348409,
title = {Search for time-independent neutrino emission from astrophysical sources with 3 yr of IceCube data},
author = {Aartsen, M. G. and Abbasi, R. and Ahlers, M. and Auffenberg, J. and Baker, M. and BenZvi, S. and Abdou, Y. and Ackermann, M. and Benabderrahmane, M. L. and Adams, J. and Aguilar, J. A. and Altmann, D. and Bai, X. and Barwick, S. W. and Baum, V. and Bay, R. and Beatty, J. J. and Bechet, S. and Tjus, J. Becker and Becker, K.-H. and and others},
abstractNote = {We present the results of a search for neutrino point sources using the IceCube data collected between 2008 April and 2011 May with three partially completed configurations of the detector: the 40-, 59-, and 79-string configurations. The live-time of this data set is 1040 days. An unbinned maximum likelihood ratio test was used to search for an excess of neutrinos above the atmospheric background at any given direction in the sky. By adding two more years of data with improved event selection and reconstruction techniques, the sensitivity was improved by a factor of 3.5 or more with respect to the previously published results obtained with the 40-string configuration of IceCube. We performed an all-sky survey and a dedicated search using a catalog of a priori selected objects observed by other telescopes. In both searches, the data are compatible with the background-only hypothesis. In the absence of evidence for a signal, we set upper limits on the flux of muon neutrinos. For an E {sup –2} neutrino spectrum, the observed limits are (0.9-5) × 10{sup –12} TeV{sup –1} cm{sup –2} s{sup –1} for energies between 1 TeV and 1 PeV in the northern sky and (0.9-23.2) × 10{sup –12} TeV{sup –1} cm{sup –2} s{sup –1} for energies between 10{sup 2} TeV and 10{sup 2} PeV in the southern sky. We also report upper limits for neutrino emission from groups of sources that were selected according to theoretical models or observational parameters and analyzed with a stacking approach. Some of the limits presented already reach the level necessary to quantitatively test current models of neutrino emission.},
doi = {10.1088/0004-637X/779/2/132},
journal = {Astrophysical Journal},
number = 2,
volume = 779,
place = {United States},
year = {Fri Dec 20 00:00:00 EST 2013},
month = {Fri Dec 20 00:00:00 EST 2013}
}
  • In this paper searches for flaring astrophysical neutrino sources and sources with periodic emission with the IceCube neutrino telescope are presented. In contrast to time-integrated searches, where steady emission is assumed, the analyses presented here look for a time-dependent signal of neutrinos using the information from the neutrino arrival times to enhance the discovery potential. A search was performed for correlations between neutrino arrival times and directions, as well as neutrino emission following time-dependent light curves, sporadic emission, or periodicities of candidate sources. These include active galactic nuclei, soft γ-ray repeaters, supernova remnants hosting pulsars, microquasars, and X-ray binaries. Themore » work presented here updates and extends previously published results to a longer period that covers 4 years of data from 2008 April 5 to 2012 May 16, including the first year of operation of the completed 86 string detector. The analyses did not find any significant time-dependent point sources of neutrinos, and the results were used to set upper limits on the neutrino flux from source candidates.« less
  • We present the results of a search for high-energy muon neutrinos with the IceCube detector in coincidence with the Crab Nebula flare reported on 2010 September by various experiments. Due to the unusual flaring state of the otherwise steady source we performed a prompt analysis of the 79-string configuration data to search for neutrinos that might be emitted along with the observed {gamma}-rays. We performed two different and complementary data selections of neutrino events in the time window of 10 days around the flare. One event selection is optimized for discovery of E{sup -2}{sub {nu}} neutrino spectrum typical of first-ordermore » Fermi acceleration. A similar event selection has also been applied to the 40-string data to derive the time-integrated limits to the neutrino emission from the Crab. The other event selection was optimized for discovery of neutrino spectra with softer spectral index and TeV energy cutoffs as observed for various Galactic sources in {gamma}-rays. The 90% confidence level (CL) best upper limits on the Crab flux during the 10 day flare are 4.73 Multiplication-Sign 10{sup -11} cm{sup -2} s{sup -1} TeV{sup -1} for an E{sup -2}{sub {nu}} neutrino spectrum and 2.50 Multiplication-Sign 10{sup -10} cm{sup -2} s{sup -1} TeV{sup -1} for a softer neutrino spectra of E{sup -2.7}{sub {nu}}, as indicated by Fermi measurements during the flare. In this paper, we also illustrate the impact of the time-integrated limit on the Crab neutrino steady emission. The limit obtained using 375.5 days of the 40-string configuration is compared to existing models of neutrino production from the Crab and its impact on astrophysical parameters is discussed. The most optimistic predictions of some models are already rejected by the IceCube neutrino telescope with more than 90% CL.« less
  • We present constraints derived from a search of four years of IceCube data for a prompt neutrino flux from gamma-ray bursts (GRBs). A single low-significance neutrino, compatible with the atmospheric neutrino background, was found in coincidence with one of the 506 observed bursts. Although GRBs have been proposed as candidate sources for ultra-high-energy cosmic rays, our limits on the neutrino flux disfavor much of the parameter space for the latest models. We also find that no more than ∼1% of the recently observed astrophysical neutrino flux consists of prompt emission from GRBs that are potentially observable by existing satellites.
  • The IceCube neutrino observatory has established the existence of a flux of high-energy astrophysical neutrinos, which is inconsistent with the expectation from atmospheric backgrounds at a significance greater than 5 σ . This flux has been observed in analyses of both track events from muon neutrino interactions and cascade events from interactions of all neutrino flavors. Searches for astrophysical neutrino sources have focused on track events due to the significantly better angular resolution of track reconstructions. To date, no such sources have been confirmed. Here we present the first search for astrophysical neutrino sources using cascades interacting in IceCube withmore » deposited energies as small as 1 TeV. No significant clustering was observed in a selection of 263 cascades collected from 2010 May to 2012 May. We show that compared to the classic approach using tracks, this statistically independent search offers improved sensitivity to sources in the southern sky, especially if the emission is spatially extended or follows a soft energy spectrum. This enhancement is due to the low background from atmospheric neutrinos forming cascade events and the additional veto of atmospheric neutrinos at declinations ≲−30°.« less