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Published October 2022 | public
Journal Article

ASAS-SN follow-up of IceCube high-energy neutrino alerts

Abstract

We report on the search for optical counterparts to IceCube neutrino alerts released between 2016 April and 2021 August with the All-Sky Automated Survey for SuperNovae (ASAS-SN). Despite the discovery of a diffuse astrophysical high-energy neutrino flux in 2013, the source of those neutrinos remains largely unknown. Since 2016, IceCube has published likely astrophysical neutrinos as public real-time alerts. Through a combination of normal survey and triggered target-of-opportunity observations, ASAS-SN obtained images within 1 h of the neutrino detection for 20 per cent (11) of all observable IceCube alerts and within one day for another 57 per cent (32). For all observable alerts, we obtained images within at least two weeks from the neutrino alert. ASAS-SN provides the only optical follow-up for about 17 per cent of IceCube's neutrino alerts. We recover the two previously claimed counterparts to neutrino alerts, the flaring-blazar TXS 0506 + 056 and the tidal disruption event AT2019dsg. We investigate the light curves of previously detected transients in the alert footprints, but do not identify any further candidate neutrino sources. We also analysed the optical light curves of Fermi 4FGL sources coincident with high-energy neutrino alerts, but do not identify any contemporaneous flaring activity. Finally, we derive constraints on the luminosity functions of neutrino sources for a range of assumed evolution models.

Additional Information

J.N. was supported by the Helmholtz Weizmann Research School on Multimessenger Astronomy, funded through the Initiative and Networking Fund of the Helmholtz Association, DESY, the Weizmann Institute, the Humboldt University of Berlin, and the University of Potsdam. Support for TdJ has been provided by NSF grants AST-1908952 and AST-1911074. RS and AF were supported by the Initiative and Networking Fund of the Helmholtz Association, Deutsches Elektronen-Synchrotron (DESY). BJS is supported by NSF grants AST-1907570, AST-1908952, AST-1920392, and AST-1911074. CSK and KZS are supported by NSF grants AST-1814440 and AST-1908570. JFB is supported by National Science Foundation grant no. PHY-2012955. Support for TW-SH was provided by NASA through the NASA Hubble Fellowship grant HST-HF2-51458.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-265. ASAS-SN is funded in part by the Gordon and Betty Moore Foundation through grants GBMF5490 and GBMF10501 to the Ohio State University, NSF grant AST-1908570, the Mt. Cuba Astronomical Foundation, the Center for Cosmology and AstroParticle Physics (CCAPP) at OSU, the Chinese Academy of Sciences South America Center for Astronomy (CAS-SACA), and the Villum Fonden (Denmark). Development of ASAS-SN has been supported by NSF grant AST-0908816, the Center for Cosmology and AstroParticle Physics at the Ohio State University, the Mt. Cuba Astronomical Foundation, and by George Skestos. Some of the results in this paper have been derived using the HEALPY and HEALPIX packages. The ZTF forced-photometry service was funded under the Heising-Simons Foundation grant no. 12540303 (PI: Graham). AF acknowledges funding from the German Science Foundation DFG, via the Collaborative Reasearch Center SFB1491 "Cosmic Interacting Matters - From Source to Signal".

Additional details

Created:
August 22, 2023
Modified:
October 24, 2023