An updated list of target sources for IceCube neutrino cluster alerts

TL;DR

This paper updates the list of astrophysical sources targeted by IceCube for neutrino cluster alerts, expanding from gamma-ray bright AGN to include X-ray bright AGN and binary systems, to enhance multimessenger astronomy efforts.

Contribution

It provides a systematic compilation of a new target source list for IceCube, broadening the scope beyond gamma-ray bright AGN to include additional astrophysical objects.

Findings

Expanded target list includes X-ray bright AGN and binary systems.

Improved sensitivity for neutrino source detection through targeted analysis.

Facilitates multimessenger observations with broader astrophysical community.

Abstract

Multimessenger astronomy seeks to uncover the origins of cosmic rays and neutrinos. The IceCube Neutrino Observatory plays a key role in monitoring the sky for revealing high energy neutrinos and neutrino time clusters possibly associated with astrophysical sources, issuing alerts to the astrophysical community for significant excesses. This enables joint observations with other astronomical facilities that could reveal the hidden mechanisms behind the most extreme environments in the Universe. In particular, since 2006 the Gamma-ray Follow-Up (GFU) program shares cluster alerts with partner Imaging Air Cherenkov Telescopes. The faint cosmic signals, searched against large atmospheric backgrounds, are widely masked by the statistical penalties that arise when scanning the full sky in an unbiased way. Hence, targeted analyses of pre-selected neutrino source candidates have proven to increase our search sensitivity. Our understanding of astrophysical environments has improved in recent years, with evidence of neutrino emission from the blazar TXS 0506+056 and the Seyfert galaxy NGC 1068. The aim of expanding observational possibilities and engaging the broader scientific community through public cluster alerts has motivated the creation of a new list of target sources to be monitored by IceCube. This contribution presents the systematic compilation of this list, which extends the well-established focus on gamma-ray bright active galactic nuclei (AGN) to include X-ray bright AGN and binary systems.