Dark matter heating of gas accreting onto sgr A

Elizabeth R. Bennewitz, Cristian Gaidau, Thomas W. Baumgarte, Stuart L. Shapiro

Research output: Contribution to journalArticle

Abstract

We study effects of heating by dark matter (DM) annihilation on black hole gas accretion. We observe that, for reasonable assumptions about DM densities in spikes around supermassive black holes, as well as DM masses and annihilation cross-sections within the standard WIMP model, heating by DM annihilation may have an appreciable effect on the accretion on to Sgr A in the Galactic Centre. Motivated by this observation we study the effects of such heating on Bondi accretion, i.e. spherically symmetric, steady-state Newtonian accretion on to a black hole. We consider different adiabatic indices for the gas, and different power-law exponents for the DM density profile. We find that typical transonic solutions with heating have a significantly reduced accretion rate. However, for many plausible parameters, transonic solutions do not exist, suggesting a breakdown of the underlying assumptions of steady-state Bondi accretion. Our findings indicate that heating by DM annihilation may play an important role in the accretion onto supermassive black holes at the centre of galaxies, and may help explain the low accretion rate observed for Sgr A

Original languageEnglish (US)
Pages (from-to)3414-3425
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume490
Issue number3
DOIs
StatePublished - Dec 1 2019

Keywords

  • Accretion
  • Accretion discs
  • Black hole physics
  • Dark matter
  • Galaxy: Centre

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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