H.E.S.S. realtime follow-ups of IceCube high-energy neutrino alerts. (arXiv:2308.16699v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bradascio_F/0/1/0/all/0/1">Federica Bradascio</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ashkar_H/0/1/0/all/0/1">Halim Ashkar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Borowska_J/0/1/0/all/0/1">Jowita Borowska</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mbarubucyeye_J/0/1/0/all/0/1">Jean Damascene Mbarubucyeye</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Oukacha_E/0/1/0/all/0/1">Enzo Oukacha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schussler_F/0/1/0/all/0/1">Fabian Sch&#xfc;ssler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Suzuki_H/0/1/0/all/0/1">Hiromasa Suzuki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wierzcholska_A/0/1/0/all/0/1">Alicja Wierzcholska</a> (for the H.E.S.S. and IceCube Collaborations)

The evidence for multi-messenger photon and neutrino emission from the blazar
TXS 0506+056 has demonstrated the importance of realtime follow-up of neutrino
events by various ground- and space-based facilities. The effort of H.E.S.S.
and other experiments in coordinating observations to obtain quasi-simultaneous
multiwavelength flux and spectrum measurements has been critical in measuring
the chance coincidence with the high-energy neutrino event IC-170922A and
constraining theoretical models. For about a decade, the H.E.S.S. transient
program has included a search for gamma-ray emission associated with
high-energy neutrino alerts, looking for gamma-ray activity from known sources
and newly detected emitters consistent with the neutrino location. In this
contribution, we present an overview of follow-up activities for realtime
neutrino alerts with H.E.S.S. in 2021 and 2022. Our analysis includes both
public IceCube neutrino alerts and alerts exchanged as part of a joint
H.E.S.S.-IceCube program. We focus on interesting coincidences observed with
gamma-ray sources, particularly highlighting the significant detection of PKS
0625-35, an AGN previously detected by H.E.S.S., and three IceCube neutrinos.

The evidence for multi-messenger photon and neutrino emission from the blazar
TXS 0506+056 has demonstrated the importance of realtime follow-up of neutrino
events by various ground- and space-based facilities. The effort of H.E.S.S.
and other experiments in coordinating observations to obtain quasi-simultaneous
multiwavelength flux and spectrum measurements has been critical in measuring
the chance coincidence with the high-energy neutrino event IC-170922A and
constraining theoretical models. For about a decade, the H.E.S.S. transient
program has included a search for gamma-ray emission associated with
high-energy neutrino alerts, looking for gamma-ray activity from known sources
and newly detected emitters consistent with the neutrino location. In this
contribution, we present an overview of follow-up activities for realtime
neutrino alerts with H.E.S.S. in 2021 and 2022. Our analysis includes both
public IceCube neutrino alerts and alerts exchanged as part of a joint
H.E.S.S.-IceCube program. We focus on interesting coincidences observed with
gamma-ray sources, particularly highlighting the significant detection of PKS
0625-35, an AGN previously detected by H.E.S.S., and three IceCube neutrinos.

http://arxiv.org/icons/sfx.gif