High Energy Gamma-Ray Emission from the Coma Cluster Region: Deep Morphological and Spectral Studies.

Discussion timeslot (ZOOM-Meeting): 16. July 2021 - 18:00
ZOOM-Meeting URL: https://icrc2021.desy.de/pf_access_abstracts
Corresponding Session: https://icrc2021-venue.desy.de/channel/Presenter-Forum-1-Evening-All-Categories/48
Abstract:
"The Coma galaxy cluster is one of the largest gravitationally-bound astrophysical structures in the local Universe, with a linear size of more than 2 Mpc and a z=0.023 distance. The relatively high intracluster density and the high-velocity accretion shocks within the cluster make it a possible source of high energy (HE) $gamma$-ray emission. Using 12.3 years of Fermi-LAT Pass 8 data between 100 MeV and 1 TeV energies, we report the detection of HE diffuse $gamma$-ray emission from the direction of the Coma cluster with $5.4 sigma$ extension significance and  R$_{68}$ = 0.82$^{circ}$ extension described with a homogeneous disk model. The corresponding $gamma$-ray spectrum extends up to $sim50$ GeV with power-law spectral index $Gamma = 2.23 pm 0.11 $ and energy flux of  $(3.48pm0.68)times10^{-12}$ erg cm$^{-2}$ s$^{-1}$. Furthermore, three point-like structures with power-law indexes of $2.44pm0.28$, $2.56pm0.32$, and $1.99pm0.30$ show improvement in the fit by $mathrm{Delta_{AIC}}=7.2$ indicating more $gamma$-ray sources in the region."

Authors: Davit Zargaryan
Co-Authors: Vardan Baghmanyan | Felix Aharonian | Sabrina Casanova | Jonathan Mackey | Ruizhi Yang
Indico-ID: 444
Proceeding URL: https://pos.sissa.it/395/582