@article{8e3b4ad58ac0422b9ecd8bbbf3db8091,
title = "Searching for VHE gamma-ray emission associated with IceCube neutrino alerts using FACT, H.E.S.S., MAGIC, and VERITAS",
abstract = "The realtime follow-up of neutrino events is a promising approach to search for astrophysical neutrino sources. It has so far provided compelling evidence for a neutrino point source: the flaring gamma-ray blazar TXS 0506+056 observed in coincidence with the high-energy neutrino IceCube-170922A detected by IceCube. The detection of very-high-energy gamma rays (VHE, E > 100 GeV) from this source helped establish the coincidence and constrained the modeling of the blazar emission at the time of the IceCube event. The four major imaging atmospheric Cherenkov telescope arrays (IACTs) - FACT, H.E.S.S., MAGIC, and VERITAS - operate an active follow-up program of target-of-opportunity observations of neutrino alerts sent by IceCube. This program has two main components. One are the observations of known gamma-ray sources around which a cluster of candidate neutrino events has been identified by IceCube (Gamma-ray Follow-Up, GFU). Second one is the follow-up of single high-energy neutrino candidate events of potential astrophysical origin such as IceCube-170922A. GFU has been recently upgraded by IceCube in collaboration with the IACT groups. We present here recent results from the IACT follow-up programs of IceCube neutrino alerts and a description of the upgraded IceCube GFU system.",
author = "{VERITAS collaboration} and {the MAGIC} and IceCube and FACT and H.E.S.S. and Daniela Dorner and Mezek, {Ga{\v s}per Kukec} and R. Abbasi and M. Ackermann and J. Adams and Aguilar, {J. A.} and M. Ahlers and M. Ahrens and C. Alispach and Alves, {A. A.} and Amin, {N. M.} and R. An and K. Andeen and T. Anderson and G. Anton and C. Arg{\"u}elles and Y. Ashida and S. Axani and X. Bai and Balagopal, {A. V.} and A. Barbano and Barwick, {S. W.} and B. Bastian and V. Basu and S. Baur and R. Bay and Beatty, {J. J.} and Becker, {K. H.} and {Becker Tjus}, J. and C. Bellenghi and S. BenZvi and D. Berley and Elisa Bernardini and Besson, {D. Z.} and G. Binder and D. Bindig and E. Blaufuss and S. Blot and M. Boddenberg and F. Bontempo and J. Borowka and S. B{\"o}ser and O. Botner and J. B{\"o}ttcher and E. Bourbeau and F. Bradascio and J. Braun and Cowen, {D. F.} and D. Fox and A. Falcone",
note = "Funding Information: USA - U.S. National Science Foundation-Office of Polar Programs, U.S. National Science Foundation-Physics Division, U.S. National Science Foundation-EPSCoR, Wisconsin Alumni Research Foundation, Center for High Throughput Computing (CHTC) at the University of Wisconsin-Madison, Open Science Grid (OSG), Extreme Science and Engineering Discovery Environment (XSEDE), Frontera computing project at the Texas Advanced Computing Center, U.S. Department of Energy-National Energy Research Scientific Computing Center, Particle astrophysics research computing center at the University of Maryland, Institute for Cyber-Enabled Research at Michigan State University, and Astroparticle physics computational facility at Marquette University; Belgium - Funds for Scientific Research (FRS-FNRS and FWO), FWO Odysseus and Big Science programmes, and Belgian Federal Science Policy Office (Belspo); Germany - Bundesministerium f{\"u}r Bildung und Forschung (BMBF), Deutsche Forschungsgemeinschaft (DFG), Helmholtz Alliance for Astroparticle Physics (HAP), Initiative and Networking Fund of the Helmholtz Association, Deutsches Elektronen Synchrotron (DESY), and High Performance Computing cluster of the RWTH Aachen; Sweden - Swedish Research Council, Swedish Polar Research Secretariat, Swedish National Infrastructure for Computing (SNIC), and Knut and Alice Wallenberg Foundation; Australia - Australian Research Council; Canada - Natural Sciences and Engineering Research Council of Canada, Calcul Qu{\'e}bec, Compute Ontario, Canada Foundation for Innovation, WestGrid, and Compute Canada; Denmark - Villum Fonden and Carlsberg Foundation; New Zealand - Marsden Fund; Japan - Japan Society for Promotion of Science (JSPS) and Institute for Global Prominent Research (IGPR) of Chiba University; Korea - National Research Foundation of Korea (NRF); Switzerland - Swiss National Science Foundation (SNSF); United Kingdom - Department of Physics, University of Oxford. Funding Information: USA – U.S. National Science Foundation-Office of Polar Programs, U.S. National Science Foundation-Physics Division, U.S. National Science Foundation-EPSCoR, Wisconsin Alumni Research Foundation, Center for High Throughput Computing (CHTC) at the University of Wisconsin–Madison, Open Science Grid (OSG), Extreme Science and Engineering Discovery Environment (XSEDE), Frontera computing project at the Texas Advanced Computing Center, U.S. Department of Energy-National Energy Research Scientific Computing Center, Particle astrophysics research computing center at the University of Maryland, Institute for Cyber-Enabled Research at Michigan State University, and Astroparticle physics computational facility at Marquette University; Belgium – Funds for Scientific Research (FRS-FNRS and FWO), FWO Odysseus and Big Science programmes, and Belgian Federal Science Policy Office (Belspo); Germany – Bundesministerium f{\"u}r Bildung und Forschung (BMBF), Deutsche Forschungsgemeinschaft (DFG), Helmholtz Alliance for Astroparticle Physics (HAP), Initiative and Networking Fund of the Helmholtz Association, Deutsches Elektronen Synchrotron (DESY), and High Performance Computing cluster of the RWTH Aachen; Sweden – Swedish Research Council, Swedish Polar Research Secretariat, Swedish National Infrastructure for Computing (SNIC), and Knut and Alice Wallenberg Foundation; Australia – Australian Funding Information: The following persons contributed to the MAGIC analyses: M. Artero (IFAE-BIST), A. Berti (MPIfP), H. B{\"o}kenkamp (U. Dortmund), A. Fattorini (U. Dortmund), L. Heckmann (MPIfP), S. Mangano (CIEMAT), H.A. Mondal (SINP), K. Noda (ICRR), S. Sakurai (ICRR), L. di Venere (INFN-Bari), I. Viale (U. Padova), S. Yoo (U. Kyoto) The members of the MAGIC Collaboration gratefully acknowledge financial support from the agencies and organizations listed here: https://magic.mpp.mpg.de/acknowledgments_ICRC2021 The members of the VERITAS Collaboration gratefully acknowledge financial support from the agencies and organizations listed here: https://veritas.sao.arizona.edu/. Funding Information: Research Council; Canada – Natural Sciences and Engineering Research Council of Canada, Calcul Qu{\'e}bec, Compute Ontario, Canada Foundation for Innovation, WestGrid, and Compute Canada; Denmark – Villum Fonden and Carlsberg Foundation; New Zealand – Marsden Fund; Japan – Japan Society for Promotion of Science (JSPS) and Institute for Global Prominent Research (IGPR) of Chiba University; Korea – National Research Foundation of Korea (NRF); Switzerland – Swiss National Science Foundation (SNSF); United Kingdom – Department of Physics, University of Oxford. Funding Information: The following persons contributed to the FACT analyses: D. Dorner (U. W{\"u}rzburg), T. Bretz (RWTH Aachen) The members of the FACT Collaboration gratefully acknowledge financial support from the agencies and organizations listed here: https://fact-project.org/collaboration/icrc2021_acknowledgements. html The following persons contributed to the IceCube analyses: T. Kintscher, M. Mallamaci, C. Bos-colo Meneguolo. The following persons contributed to the H.E.S.S. analyses: H. Ashkar (IRFU), Y. Becherini (LNU), M. Cerruti (APC), C. Hoischen (Uni. Potsdam), R. Konno (Desy), F. Sch{\"u}ssler (IRFU), M. Senniappan (LNU). The members of the H.E.S.S. Collaboration gratefully acknowledge financial support from the agencies and organizations listed here: https://www.mpi-hd.mpg.de/hfm/HESS/pages/publications/ auxiliary/HESS-Acknowledgements-2021.html. FS acknowledges support for this work by the Programme National des Hautes Energies of CNRS/INSU with INP and IN2P3, co-funded by CEA and CNES. Publisher Copyright: {\textcopyright} Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0); 37th International Cosmic Ray Conference, ICRC 2021 ; Conference date: 12-07-2021 Through 23-07-2021",
year = "2022",
month = mar,
day = "18",
language = "English (US)",
volume = "395",
journal = "Proceedings of Science",
issn = "1824-8039",
publisher = "Sissa Medialab Srl",
}