Investigation of Two Fermi-LAT Gamma-Ray Blazars Coincident with High-energy Neutrinos Detected by IceCube

IceCube Collaboration

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

After the identification of the gamma-ray blazar TXS 0506+056 as the first compelling IceCube neutrino source candidate, we perform a systematic analysis of all high-energy neutrino events satisfying the IceCube realtime trigger criteria. We find one additional known gamma-ray source, the blazar GB6 J1040+0617, in spatial coincidence with a neutrino in this sample. The chance probability of this coincidence is 30% after trial correction. For the first time, we present a systematic study of the gamma-ray flux, spectral and optical variability, and multiwavelength behavior of GB6 J1040+0617 and compare it to TXS 0506+056. We find that TXS 0506+056 shows strong flux variability in the Fermi-Large Area Telescope gamma-ray band, being in an active state around the arrival of IceCube-170922A, but in a low state during the archival IceCube neutrino flare in 2014/15. In both cases the spectral shape is statistically compatible (≤2σ) with the average spectrum showing no indication of a significant relative increase of a high-energy component. While the association of GB6 J1040+0617 with the neutrino is consistent with background expectations, the source appears to be a plausible neutrino source candidate based on its energetics and multiwavelength features, namely a bright optical flare and modestly increased gamma-ray activity. Finding one or two neutrinos originating from gamma-ray blazars in the given sample of high-energy neutrinos is consistent with previously derived limits of neutrino emission from gamma-ray blazars, indicating the sources of the majority of cosmic high-energy neutrinos remain unknown.

Original languageEnglish (US)
Article number103
JournalAstrophysical Journal
Volume880
Issue number2
DOIs
StatePublished - Aug 1 2019

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blazars
neutrinos
gamma rays
energy
energetics
flares
gamma ray telescopes
arrivals
indication
actuators

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

@article{e75f6d2d403f463b8a75afd9eca7b2df,
title = "Investigation of Two Fermi-LAT Gamma-Ray Blazars Coincident with High-energy Neutrinos Detected by IceCube",
abstract = "After the identification of the gamma-ray blazar TXS 0506+056 as the first compelling IceCube neutrino source candidate, we perform a systematic analysis of all high-energy neutrino events satisfying the IceCube realtime trigger criteria. We find one additional known gamma-ray source, the blazar GB6 J1040+0617, in spatial coincidence with a neutrino in this sample. The chance probability of this coincidence is 30{\%} after trial correction. For the first time, we present a systematic study of the gamma-ray flux, spectral and optical variability, and multiwavelength behavior of GB6 J1040+0617 and compare it to TXS 0506+056. We find that TXS 0506+056 shows strong flux variability in the Fermi-Large Area Telescope gamma-ray band, being in an active state around the arrival of IceCube-170922A, but in a low state during the archival IceCube neutrino flare in 2014/15. In both cases the spectral shape is statistically compatible (≤2σ) with the average spectrum showing no indication of a significant relative increase of a high-energy component. While the association of GB6 J1040+0617 with the neutrino is consistent with background expectations, the source appears to be a plausible neutrino source candidate based on its energetics and multiwavelength features, namely a bright optical flare and modestly increased gamma-ray activity. Finding one or two neutrinos originating from gamma-ray blazars in the given sample of high-energy neutrinos is consistent with previously derived limits of neutrino emission from gamma-ray blazars, indicating the sources of the majority of cosmic high-energy neutrinos remain unknown.",
author = "{IceCube Collaboration} and Collaboration, {Fermi Lat} and Collaboration, {Asas Sn} and S. Garrappa and S. Buson and A. Franckowiak and Shappee, {B. J.} and Beacom, {J. F.} and S. Dong and Holoien, {T. W.S.} and Kochanek, {C. S.} and Prieto, {J. L.} and Stanek, {K. Z.} and Thompson, {T. A.} and Aartsen, {M. G.} and M. Ackermann and J. Adams and Aguilar, {J. A.} and M. Ahlers and M. Ahrens and C. Alispach and K. Andeen and T. Anderson and I. Ansseau and G. Anton and C. Arg{\"u}elles and J. Auffenberg and S. Axani and P. Backes and H. Bagherpour and X. Bai and A. Barbano and Barwick, {S. W.} and V. Baum and R. Bay and Beatty, {J. J.} and Becker, {K. H.} and Tjus, {J. Becker} and S. Benzvi and D. Berley and E. Bernardini and Besson, {D. Z.} and G. Binder and D. Bindig and E. Blaufuss and S. Blot and C. Bohm and M. B{\"o}rner and S. B{\"o}ser and O. Botner and E. Bourbeau",
year = "2019",
month = "8",
day = "1",
doi = "10.3847/1538-4357/ab2ada",
language = "English (US)",
volume = "880",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "2",

}

Investigation of Two Fermi-LAT Gamma-Ray Blazars Coincident with High-energy Neutrinos Detected by IceCube. / IceCube Collaboration.

In: Astrophysical Journal, Vol. 880, No. 2, 103, 01.08.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Investigation of Two Fermi-LAT Gamma-Ray Blazars Coincident with High-energy Neutrinos Detected by IceCube

AU - IceCube Collaboration

AU - Collaboration, Fermi Lat

AU - Collaboration, Asas Sn

AU - Garrappa, S.

AU - Buson, S.

AU - Franckowiak, A.

AU - Shappee, B. J.

AU - Beacom, J. F.

AU - Dong, S.

AU - Holoien, T. W.S.

AU - Kochanek, C. S.

AU - Prieto, J. L.

AU - Stanek, K. Z.

AU - Thompson, T. A.

AU - Aartsen, M. G.

AU - Ackermann, M.

AU - Adams, J.

AU - Aguilar, J. A.

AU - Ahlers, M.

AU - Ahrens, M.

AU - Alispach, C.

AU - Andeen, K.

AU - Anderson, T.

AU - Ansseau, I.

AU - Anton, G.

AU - Argüelles, C.

AU - Auffenberg, J.

AU - Axani, S.

AU - Backes, P.

AU - Bagherpour, H.

AU - Bai, X.

AU - Barbano, A.

AU - Barwick, S. W.

AU - Baum, V.

AU - Bay, R.

AU - Beatty, J. J.

AU - Becker, K. H.

AU - Tjus, J. Becker

AU - Benzvi, S.

AU - Berley, D.

AU - Bernardini, E.

AU - Besson, D. Z.

AU - Binder, G.

AU - Bindig, D.

AU - Blaufuss, E.

AU - Blot, S.

AU - Bohm, C.

AU - Börner, M.

AU - Böser, S.

AU - Botner, O.

AU - Bourbeau, E.

PY - 2019/8/1

Y1 - 2019/8/1

N2 - After the identification of the gamma-ray blazar TXS 0506+056 as the first compelling IceCube neutrino source candidate, we perform a systematic analysis of all high-energy neutrino events satisfying the IceCube realtime trigger criteria. We find one additional known gamma-ray source, the blazar GB6 J1040+0617, in spatial coincidence with a neutrino in this sample. The chance probability of this coincidence is 30% after trial correction. For the first time, we present a systematic study of the gamma-ray flux, spectral and optical variability, and multiwavelength behavior of GB6 J1040+0617 and compare it to TXS 0506+056. We find that TXS 0506+056 shows strong flux variability in the Fermi-Large Area Telescope gamma-ray band, being in an active state around the arrival of IceCube-170922A, but in a low state during the archival IceCube neutrino flare in 2014/15. In both cases the spectral shape is statistically compatible (≤2σ) with the average spectrum showing no indication of a significant relative increase of a high-energy component. While the association of GB6 J1040+0617 with the neutrino is consistent with background expectations, the source appears to be a plausible neutrino source candidate based on its energetics and multiwavelength features, namely a bright optical flare and modestly increased gamma-ray activity. Finding one or two neutrinos originating from gamma-ray blazars in the given sample of high-energy neutrinos is consistent with previously derived limits of neutrino emission from gamma-ray blazars, indicating the sources of the majority of cosmic high-energy neutrinos remain unknown.

AB - After the identification of the gamma-ray blazar TXS 0506+056 as the first compelling IceCube neutrino source candidate, we perform a systematic analysis of all high-energy neutrino events satisfying the IceCube realtime trigger criteria. We find one additional known gamma-ray source, the blazar GB6 J1040+0617, in spatial coincidence with a neutrino in this sample. The chance probability of this coincidence is 30% after trial correction. For the first time, we present a systematic study of the gamma-ray flux, spectral and optical variability, and multiwavelength behavior of GB6 J1040+0617 and compare it to TXS 0506+056. We find that TXS 0506+056 shows strong flux variability in the Fermi-Large Area Telescope gamma-ray band, being in an active state around the arrival of IceCube-170922A, but in a low state during the archival IceCube neutrino flare in 2014/15. In both cases the spectral shape is statistically compatible (≤2σ) with the average spectrum showing no indication of a significant relative increase of a high-energy component. While the association of GB6 J1040+0617 with the neutrino is consistent with background expectations, the source appears to be a plausible neutrino source candidate based on its energetics and multiwavelength features, namely a bright optical flare and modestly increased gamma-ray activity. Finding one or two neutrinos originating from gamma-ray blazars in the given sample of high-energy neutrinos is consistent with previously derived limits of neutrino emission from gamma-ray blazars, indicating the sources of the majority of cosmic high-energy neutrinos remain unknown.

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U2 - 10.3847/1538-4357/ab2ada

DO - 10.3847/1538-4357/ab2ada

M3 - Article

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VL - 880

JO - Astrophysical Journal

JF - Astrophysical Journal

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