Pair Drizzle around Sub-Eddington Supermassive Black Holes

George N. Wong, Benjamin R. Ryan, Charles F. Gammie

Research output: Contribution to journalArticlepeer-review


Electron-positron pair creation near sub-Eddington accretion rate black holes is believed to be dominated by the Breit-Wheeler process (photon-photon collisions). The interacting high-energy photons are produced when unscreened electric fields accelerate leptons either in coherent, macroscopic gaps, or in incoherent structures embedded in the turbulent plasma flow. The latter type of acceleration results in a drizzle of pair production sourced by photons from the background radiation field whose energies are near the pair-production threshold. In this work, we use radiation general relativistic magnetohydrodynamic simulations to extend an earlier study of pair drizzle by Mościbrodzka et al. We focus on low-magnetization (standard and normal evolution) accretion onto supermassive Kerr black holes and consider radiation due to synchrotron, bremsstrahlung, and Compton upscattering processes. We confirm that pair drizzle in M87 is sufficient to keep the magnetospheric charge density orders of magnitude above the Goldreich-Julian density. We also find that pair production peaks along the jet-disk boundary.

Original languageEnglish (US)
Article number73
JournalAstrophysical Journal
Issue number2
StatePublished - Feb 1 2021

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Pair Drizzle around Sub-Eddington Supermassive Black Holes'. Together they form a unique fingerprint.

Cite this