Neutrino and pair creation in reconnection-powered coronae of accreting black holes
D. Karavola, M. Petropoulou, D. F. G. Fiorillo, L. Comisso, L. Sironi
arXiv:2410.12638v2 Announce Type: replace
Abstract: A ubiquitous feature of accreting black hole systems is their hard X-ray emission which is thought to be produced through Comptonization of soft photons by electrons and positrons in the vicinity of the black hole, in a region with optical depth of order unity. The origin and composition of this Comptonizing region, known as the corona, is a matter open for debate. In this paper we investigate the role of relativistic protons accelerated in black-hole magnetospheric current sheets for the pair enrichment and neutrino emission of AGN coronae. Our model has two free parameters, namely the proton plasma magnetization $sigma_{rm p}$, which controls the peak energy of the neutrino spectrum, and the Eddington ratio $lambda_{rm Edd}$ (defined as the ratio between X-ray luminosity $L_{rm X}$ and Eddington luminosity $L_{rm Edd}$), which controls the amount of energy transferred to secondary particles. For sources with $lambda_{rm Edd} gtrsim lambda_{rm Edd, crit}$ (where $lambda_{rm Edd, crit} sim 10^{-1}$ for $sigma_{rm p}=10^5$ or $sim 10^{-2}$ for $sigma_{rm p}=10^7$), proton-photon interactions and $ gamma gamma$ annihilation produce enough secondary pairs to achieve Thomson optical depths $tau_{rm T} sim 0.1-10$. Additionally, we find that the neutrino luminosity scales as $L^2_{rm X}/L_{rm Edd}$ for $lambda_{rm Edd} lesssim lambda_{rm Edd, crit}$, while it is proportional to $L_{rm X}$ for higher $lambda_{rm Edd}$ values. We apply our model to four Seyfert galaxies, including NGC 1068, and discuss our results in light of recent IceCube observations.arXiv:2410.12638v2 Announce Type: replace
Abstract: A ubiquitous feature of accreting black hole systems is their hard X-ray emission which is thought to be produced through Comptonization of soft photons by electrons and positrons in the vicinity of the black hole, in a region with optical depth of order unity. The origin and composition of this Comptonizing region, known as the corona, is a matter open for debate. In this paper we investigate the role of relativistic protons accelerated in black-hole magnetospheric current sheets for the pair enrichment and neutrino emission of AGN coronae. Our model has two free parameters, namely the proton plasma magnetization $sigma_{rm p}$, which controls the peak energy of the neutrino spectrum, and the Eddington ratio $lambda_{rm Edd}$ (defined as the ratio between X-ray luminosity $L_{rm X}$ and Eddington luminosity $L_{rm Edd}$), which controls the amount of energy transferred to secondary particles. For sources with $lambda_{rm Edd} gtrsim lambda_{rm Edd, crit}$ (where $lambda_{rm Edd, crit} sim 10^{-1}$ for $sigma_{rm p}=10^5$ or $sim 10^{-2}$ for $sigma_{rm p}=10^7$), proton-photon interactions and $ gamma gamma$ annihilation produce enough secondary pairs to achieve Thomson optical depths $tau_{rm T} sim 0.1-10$. Additionally, we find that the neutrino luminosity scales as $L^2_{rm X}/L_{rm Edd}$ for $lambda_{rm Edd} lesssim lambda_{rm Edd, crit}$, while it is proportional to $L_{rm X}$ for higher $lambda_{rm Edd}$ values. We apply our model to four Seyfert galaxies, including NGC 1068, and discuss our results in light of recent IceCube observations.