Karlsruhe 2024 – scientific programme

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T: Fachverband Teilchenphysik

T 10: Gamma astronomy 1

T 10.7: Talk

Monday, March 4, 2024, 17:30–17:45, Geb. 30.22: kl. HS A

On the possible jet contribution to the γ-ray luminosity in NGC 1068 — •Silvia Salvatore^1,2, Björn Eichmann^1,2, Xavier Rodrigues^2,3,4, Ralf-Jürgen Dettmar^2,4, and Julia Becker Tjus^1,2,5 — ¹Theoretische Physik IV, Ruhr-Universität Bochum, Bochum, Germany — ²RAPP-Center, Ruhr-Universität Bochum, Bochum, Germany — ³European Southern Observatory, Garching bei München, Germany — ⁴Astronomisches Institut (AIRUB), Ruhr-Universität Bochum, Bochum, Germany — ⁵Department of Space, Earth and Environment, Chalmers University of Technology, 412 96 Gothenburg, Sweden

NGC 1068 is a widely studied Seyfert II galaxy with a broad energy band, from radio to gamma-ray emissions. A strong evidence for high-energy neutrino emission was recently discovered by IceCube. In this work, we focus on the gamma-ray emission and in particular we discuss whether the radio jet can be a source of the gamma rays between 0.1 and 100 GeV, as observed by Fermi-LAT. We include both leptonic and hadronic processes and use spatially resolved VLBA and ALMA observations of the radio knot structures to constrain our calculations. Our results show that the best leptonic scenario for the prediction of the Fermi-LAT data is provided by the radio knot observed at 15 pc from the central engine. For this knot, a magnetic field strength of about 1 mG is needed as well as a strong spectral softening of the relativistic electron distribution at 1-10 GeV. We show that both these conditions cannot meet and that there is no other jet emission scenario able to explain the gamma-ray signal in the entire Fermi-LAT band.

Keywords: jet; NGC1068; Seyfert; leptonic; hadronic