Does absorption against AGN reveal supermassive black hole accretion?

Tom Rose, B. R. McNamara, F. Combes, A. C. Edge, A. C. Fabian, M. Gaspari, H. Russell, P. Salomé, G. Tremblay, G. Ferland

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Galaxies often contain large reservoirs of molecular gas that shape their evolution. This can be through cooling of the gas - which leads to star formation, or accretion on to the central supermassive black hole - which fuels active galactic nucleus (AGN) activity and produces powerful feedback. Molecular gas has been detected in early-type galaxies on scales of just a few tens to hundreds of solar masses by searching for absorption against their compact radio cores. Using this technique, ALMA has found absorption in several brightest cluster galaxies, some of which show molecular gas moving towards their galaxy's core at hundreds of km s-1. In this paper, we constrain the location of this absorbing gas by comparing each galaxy's molecular emission and absorption. In four galaxies, the absorption properties are consistent with chance alignments between the continuum and a fraction of the molecular clouds visible in emission. In four others, the properties of the absorption are inconsistent with this scenario. In these systems, the absorption is likely produced by a separate population of molecular clouds in close proximity to the galaxy core and with high inward velocities and velocity dispersions. We thus deduce the existence of two types of absorber, caused by chance alignments between the radio core and: (i) a fraction of the molecular clouds visible in emission, and (ii) molecular clouds close to the AGN, in the process of accretion. We also present the first ALMA observations of molecular emission in S555, Abell 2390, RXC J1350.3+0940, and RXC J1603.6+1553 - with the latter three having Mmol > 1010 Mθ.

Original languageEnglish
Pages (from-to)878-892
Number of pages15
JournalMonthly Notices of the Royal Astronomical Society
Volume518
Issue number1
DOIs
StatePublished - Jan 1 2023

Bibliographical note

Publisher Copyright:
© 2022 The Author(s).

Keywords

  • ISM: molecules
  • galaxies: ISM
  • quasars: absorption lines

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint

Dive into the research topics of 'Does absorption against AGN reveal supermassive black hole accretion?'. Together they form a unique fingerprint.

Cite this