Neutrino heating near hyper-accreting black holes

TL;DR

This paper calculates the efficiency of neutrino-induced energy deposition near hyper-accreting black holes, revealing its dependence on accretion rate and black hole spin, which helps identify potential GRB progenitors.

Contribution

It provides a fully relativistic, geodesic-tracing calculation of neutrino heating efficiency, highlighting its key dependencies and independence from neutrino transport details in the opaque zone.

Findings

Neutrino heating efficiency depends on accretion rate and black hole spin.

Efficiency is largely independent of neutrino transport details in the opaque zone.

Results identify conditions under which accretion discs can power GRBs.

Abstract

Hyper-accretion discs around black holes emit copious neutrinos and anti-neutrinos. A fraction of the emitted neutrinos convert to electron-positron plasma above the disc through the annihilation reaction $\nu\bar\nu\to e^+e^-$. This process may drive relativistic jets associated with GRB explosions. We calculate the efficiency of energy deposition by neutrinos. Our calculation is fully relativistic and based on a geodesic-tracing method. We find that the efficiency of neutrino heating is a well-defined function of (i) accretion rate and (ii) spin of the black hole. It is practically independent of the details of neutrino transport in the opaque zone of the disc. The results help identify accretion discs whose neutrino emission can power GRBs.