TY - JOUR
T1 - Search for steady point-like sources in the astrophysical muon neutrino flux with 8 years of IceCube data
AU - Aartsen, M.G.
AU - Ackermann, M.
AU - Adams, J.
AU - Aguilar, J.A.
AU - Ahlers, Markus Tobias
AU - Bourbeau, Etienne
AU - Larson, Michael James
AU - Medici, Morten Ankersen
AU - Sarkar, Subir
AU - Stuttard, Thomas Simon
AU - Koskinen, D. Jason
AU - Rameez, M
AU - Ahrens, M.
AU - Altman, D.
AU - Andeen, K.
AU - Anderson, T.
AU - Ansseau, I
AU - Icecube Collaboration
PY - 2019/3/1
Y1 - 2019/3/1
N2 - The IceCube Collaboration has observed a high-energy astrophysical neutrino flux and recently found evidence for neutrino emission from the blazar TXS 0506+ 056. These results open a new window into the high-energy universe. However, the source or sources of most of the observed flux of astrophysical neutrinos remains uncertain. Here, a search for steady point-like neutrino sources is performed using an unbinned likelihood analysis. The method searches for a spatial accumulation of muon-neutrino events using the very high-statistics sample of about 497,000 neutrinos recorded by IceCube between 2009 and 2017. The median angular resolution is ∼ 1 ∘ at 1 TeV and improves to ∼ 0. 3 ∘ for neutrinos with an energy of 1 PeV. Compared to previous analyses, this search is optimized for point-like neutrino emission with the same flux-characteristics as the observed astrophysical muon-neutrino flux and introduces an improved event-reconstruction and parametrization of the background. The result is an improvement in sensitivity to the muon-neutrino flux compared to the previous analysis of ∼ 35 % assuming an E - 2 spectrum. The sensitivity on the muon-neutrino flux is at a level of E2dN/dE=3·10-13TeVcm-2s-1. No new evidence for neutrino sources is found in a full sky scan and in an a priori candidate source list that is motivated by gamma-ray observations. Furthermore, no significant excesses above background are found from populations of sub-threshold sources. The implications of the non-observation for potential source classes are discussed.
AB - The IceCube Collaboration has observed a high-energy astrophysical neutrino flux and recently found evidence for neutrino emission from the blazar TXS 0506+ 056. These results open a new window into the high-energy universe. However, the source or sources of most of the observed flux of astrophysical neutrinos remains uncertain. Here, a search for steady point-like neutrino sources is performed using an unbinned likelihood analysis. The method searches for a spatial accumulation of muon-neutrino events using the very high-statistics sample of about 497,000 neutrinos recorded by IceCube between 2009 and 2017. The median angular resolution is ∼ 1 ∘ at 1 TeV and improves to ∼ 0. 3 ∘ for neutrinos with an energy of 1 PeV. Compared to previous analyses, this search is optimized for point-like neutrino emission with the same flux-characteristics as the observed astrophysical muon-neutrino flux and introduces an improved event-reconstruction and parametrization of the background. The result is an improvement in sensitivity to the muon-neutrino flux compared to the previous analysis of ∼ 35 % assuming an E - 2 spectrum. The sensitivity on the muon-neutrino flux is at a level of E2dN/dE=3·10-13TeVcm-2s-1. No new evidence for neutrino sources is found in a full sky scan and in an a priori candidate source list that is motivated by gamma-ray observations. Furthermore, no significant excesses above background are found from populations of sub-threshold sources. The implications of the non-observation for potential source classes are discussed.
U2 - 10.1140/epjc/s10052-019-6680-0
DO - 10.1140/epjc/s10052-019-6680-0
M3 - Journal article
SN - 1434-6044
VL - 79
JO - European Physical Journal C
JF - European Physical Journal C
IS - 3
M1 - 234
ER -