Probing Light Dark Matter through Cosmic-Ray Cooling in Active Galactic Nuclei

TL;DR

This paper proposes using cosmic-ray cooling in active galactic nuclei as a novel method to detect and constrain light dark matter interactions, leveraging recent high-energy neutrino observations.

Contribution

It introduces a new astrophysical probe for dark matter-proton and dark matter-electron scatterings near supermassive black holes in AGN.

Findings

Constraints on sub-GeV dark matter are the strongest to date.

Current multimessenger observations can already probe some thermal light dark matter models.

Dark matter interactions could significantly influence cosmic-ray cooling in AGN environments.

Abstract

Recent observations of high-energy neutrinos from active galactic nuclei (AGN), NGC 1068 and TXS 0506+056, 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 central 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.