Jul 12 – 23, 2021
Europe/Berlin timezone

Excited isomer photons and the VHE emission from Centaurus A

Jul 13, 2021, 12:00 PM
1h 30m


Talk CRI | Cosmic Ray Indirect Discussion


Leonel Raul Morejon (Z_THAT (Theoretische Astroteilchenphysik))


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.
Our 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.


AGN; UHECR; VHE gammas; nuclei

Subcategory Theoretical Results

Primary authors

Leonel Raul Morejon (Z_THAT (Theoretische Astroteilchenphysik)) Xavier de Sousa Ferreira Rodrigues (Z_NA (Neutrinoastronomie / Kosmologie)) Annika Rudolph (Z_THAT (Theoretische Astroteilchenphysik)) Shan Gao (DESY) Walter Winter (DESY)

Presentation materials