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Main Authors: Karwin, Chris, Khatiya, Nikita, Boughelilba, Margot, Zhao, Xiurui, Reimer, Anita, Ajello, Marco
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2604.05028
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author Karwin, Chris
Khatiya, Nikita
Boughelilba, Margot
Zhao, Xiurui
Reimer, Anita
Ajello, Marco
author_facet Karwin, Chris
Khatiya, Nikita
Boughelilba, Margot
Zhao, Xiurui
Reimer, Anita
Ajello, Marco
contents A majority of the active galactic nuclei (AGN) in the local Universe are classified as low-luminosity AGN (LLAGN), having bolometric luminosities $\lesssim 10^{42} \ \mathrm{erg \ s^{-1}}$. Although high-energy gamma-ray emission is predicted from both the jets and disks of LLAGN, to date only four have been detected by the Fermi Large Area Telescope (Fermi-LAT). In this work, we therefore conduct a comprehensive study of all the LLAGN from the Palomar spectroscopic survey of bright, northern galaxies, including both subthreshold and detected gamma-ray sources, using 14.4 years of LAT data. Our analysis results in a new detection of one LLAGN, as well as a detection of the subthreshold population using a stacking technique. We find that the signal from the subthreshold sample is consistent with being dominated by star-formation activity, although a contribution from compact jets or a mixed contribution from jetted and non-jetted systems is also feasible. On the other hand, the individually detected LLAGN are likely dominated by jet emission. We perform detailed spectral modeling for a subset of these sources and find that the gamma-ray signal can be explained by synchrotron self-Compton radiation, if the inner jet emission region is weakly magnetized with its total energy density being strongly particle dominated, and only slowly moving. With this work we also publicly release our Python-based stacking library for analyzing subthreshold source populations with the LAT, based on a proven technique used in numerous studies.
format Preprint
id arxiv_https___arxiv_org_abs_2604_05028
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Characterizing the Gamma-ray Emission from Low-Luminosity AGN
Karwin, Chris
Khatiya, Nikita
Boughelilba, Margot
Zhao, Xiurui
Reimer, Anita
Ajello, Marco
High Energy Astrophysical Phenomena
A majority of the active galactic nuclei (AGN) in the local Universe are classified as low-luminosity AGN (LLAGN), having bolometric luminosities $\lesssim 10^{42} \ \mathrm{erg \ s^{-1}}$. Although high-energy gamma-ray emission is predicted from both the jets and disks of LLAGN, to date only four have been detected by the Fermi Large Area Telescope (Fermi-LAT). In this work, we therefore conduct a comprehensive study of all the LLAGN from the Palomar spectroscopic survey of bright, northern galaxies, including both subthreshold and detected gamma-ray sources, using 14.4 years of LAT data. Our analysis results in a new detection of one LLAGN, as well as a detection of the subthreshold population using a stacking technique. We find that the signal from the subthreshold sample is consistent with being dominated by star-formation activity, although a contribution from compact jets or a mixed contribution from jetted and non-jetted systems is also feasible. On the other hand, the individually detected LLAGN are likely dominated by jet emission. We perform detailed spectral modeling for a subset of these sources and find that the gamma-ray signal can be explained by synchrotron self-Compton radiation, if the inner jet emission region is weakly magnetized with its total energy density being strongly particle dominated, and only slowly moving. With this work we also publicly release our Python-based stacking library for analyzing subthreshold source populations with the LAT, based on a proven technique used in numerous studies.
title Characterizing the Gamma-ray Emission from Low-Luminosity AGN
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2604.05028