DOE OSTI · 3021905
Neutrino and pair creation in reconnection-powered coronae of accreting black holes
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 σ p , which controls the peak energy of the neutrino spectrum, and the Eddington ratio λ X,Edd (defined as the ratio between X-ray luminosity L X and Eddington luminosity L Edd ), which controls the amount of energy transferred to secondary particles. For sources with λ X,Edd ≳ λ Edd,crit (where λ Edd,crit ∼ 10 -1 for σ p = 10 5 or ∼ 10 -2 for σ p = 10 7 ), proton-photon interactions and γγ annihilation produce enough secondary pairs to achieve Thomson optical depths τ T ∼ 0.1-10. In the opposite case of λ X,Edd ≲ λ Edd,crit , the coronal pairs cannot originate only from hadronic interactions. Additionally, we find that the neutrino luminosity scales as L 2 X /L Edd for λ X,Edd ≲ λ Edd,crit , while it is proportional to L X for higher λ X,Edd values. We apply our model to four Seyfert galaxies, including NGC 1068, and discuss our results in light of recent IceCube observations.
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Karavola, D. [National and Kapodistrian University of Athens (Greece)] (ORCID:0000000223833860), Petropoulou, M. [National and Kapodistrian University of Athens (Greece); Institute of Accelerating Systems & Applications, Athens (Greece)] (ORCID:0000000166400179), Fiorillo, D. F. G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)] (ORCID:0000000349279850), Comisso, L. [Columbia University, New York, NY (United States)] (ORCID:0000000188228031), Sironi, L. [Columbia University, New York, NY (United States); Flatiron Institute, New York, NY (United States)] (ORCID:0000000212272754). 2025-04-29. Neutrino and pair creation in reconnection-powered coronae of accreting black holes. https://doi.org/10.1088/1475-7516%2F2025%2F04%2F075
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