Probing light dark matter through cosmic-ray cooling in active galactic nuclei
Gonzalo Herrera (Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, 80805 München, Germany, Physik-Department, Technische Universität München, James-Franck-Straße, 85748 Garching, Germany); Kohta Murase (School of Natural Sciences, Institute for Advanced Study, Princeton, New Jersey 08540, USA, Department of Physics; Department of Astronomy and Astrophysics; Center for Multimessenger Astrophysics, Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, Pennsylvania 16802, USA, Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto, Kyoto 606-8502, Japan)
Recent observations of high-energy neutrinos from active galactic nuclei (AGN), NGC 1068 and TXS , suggest that cosmic rays (CRs) are accelerated in the vicinity of the central supermassive black hole and high-energy protons and electrons can cool efficiently via interactions with ambient photons and gas. The dark matter density may be significantly enhanced near the black hole, and CRs could lose energies predominantly due to scatterings with the ambient dark matter particles. We propose CR cooling in AGN as a new probe of dark matter-proton and dark matter-electron scatterings. Under plausible astrophysical assumptions, our constraints on sub-GeV dark matter can be the strongest derived to date. Some of the parameter space favored by thermal light dark matter models might already be probed with current multimessenger observations of AGN.
