Prospects for gamma-ray observations of Hercules cluster

TL;DR

This paper models the potential gamma-ray and neutrino signals from the Hercules galaxy cluster, assessing the detectability with current and future observatories to understand cosmic ray interactions in galaxy clusters.

Contribution

It provides the first detailed simulation of non-thermal hadronic gamma-ray and neutrino emission from the Hercules cluster, evaluating detection prospects with multiple observatories.

Findings

Potential gamma-ray signals could be detectable by CTA and IceCube-Gen2.

Current detectors like Fermi-LAT and IceCube may have limited sensitivity.

The study highlights the importance of galaxy clusters in cosmic ray research.

Abstract

Galaxy clusters (GCs) are the largest and most massive gravitationally bound objects in the large-scale structure of the Universe. Due to keV temperatures of virialized gas in the intracluster medium (ICM) and presence of cosmic rays (CRs), GCs are effective sources of thermal X-ray radiation and non-thermal leptonic (synchrotron) radio emission. GCs are also store-rooms for hadronic CRs, but non-thermal hadronic gamma-ray emission (mainly, due to pp collisions and subsequent pion decay) from GCs has not been detected yet. In this work we simulate the expected non-thermal hadronic gamma-ray and neutrino emission from dominant part of Hercules cluster - GC A2151 - and estimate a perspective of detection of this emission by existing (Fermi-LAT, LHASSO, IceCube) and planned (CTA, IceCube-Gen2) ground-based ans space-based detectors.