Excited isomer photons and the VHE emission from Centaurus A

Discussion timeslot (ZOOM-Meeting): 13. July 2021 - 12:00
ZOOM-Meeting URL: https://desy.zoom.us/j/92210078166
ZOOM-Meeting ID: 92210078166
ZOOM-Meeting Passcode: ICRC2021
Corresponding Session: https://icrc2021-venue.desy.de/channel/02-Constraining-UHECR-sources-CRI/63
Live-Stream URL: https://icrc2021-venue.desy.de/livestream/Discussion-03/4

Abstract:
'The very-high-energy (VHE) emission from Centaurus A (Cen A) observed by the H.E.S.S. telescopes cannot be explained by simple synchrotron-self-Compton (SSC) models. Motivated by the reported UHECR hotspot in the direction of Cen A, we investigate a scenario in which excited isomer photons of heavy nuclei can account for these VHE photons.rnOur fully self-consistent model includes a leptonic SSC scenario with a hadronic high-energy component from the pc-scale core region which explains the SED below TeV energies. As expected, the core of the jet is optically thick to above TeV gamma-rays that are produced in nuclear disintegrations. However, of a fraction of excited isomers produced in photodisintegration interactions of cosmic-ray nuclei is long-lived enough for the isomers to escape the core region. We consider the isomeric emission produced in the decay of these isomers in a larger volume surrounding the core and show that it can explain the H.E.S.S. flux while being in agreement with the spatially extended emission region recently reported.'

Authors: Leonel Raul Morejon | Xavier Rodrigues | Annika Rudolph | Shan Gao | Walter Winter
Indico-ID: 1416
Proceeding URL: https://pos.sissa.it/395/490