skip to main content

SciTech ConnectSciTech Connect

Title: RELICS OF GALAXY MERGING: OBSERVATIONAL PREDICTIONS FOR A WANDERING MASSIVE BLACK HOLE AND ACCOMPANYING STAR CLUSTER IN THE HALO OF M31

Galaxies and massive black holes (BHs) presumably grow via galactic merging events and subsequent BH coalescence. As a case study, we investigate the merging event between the Andromeda galaxy (M31) and a satellite galaxy. We compute the expected observational appearance of the massive BH that was at the center of the satellite galaxy prior to the merger and is currently wandering in the M31 halo. We demonstrate that a radiatively inefficient accretion flow with a bolometric luminosity of a few tens of solar luminosities develops when Hoyle-Lyttleton accretion onto the BH is assumed. We compute the associated broadband spectrum and show that the radio band (observable with EVLA, ALMA, and the Square Kilometre Array) is the best frequency range in which to detect the emission. We also evaluate the mass and the luminosity of the stars bound by the wandering BH and find that such a star cluster is sufficiently luminous that it could correspond to one of the star clusters found by the PAndAS survey. The discovery of a relic massive BH wandering in a galactic halo will provide a direct means of investigating in detail the coevolution of galaxies and BHs. It also means a new population ofmore » BHs (off-center massive BHs) and offers targets for clean BH imaging that avoid strong interstellar scattering in the centers of galaxies.« less
Authors:
 [1] ;  [2] ; ;  [3]
  1. Astronomy Data Center, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)
  2. Department of Astronomical Science, The Graduate University for Advanced Studies (SOKENDAI), Mitaka, Tokyo 181-8588 (Japan)
  3. Center for Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan)
Publication Date:
OSTI Identifier:
22365744
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 789; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BLACK HOLES; BOLOMETERS; COALESCENCE; GALACTIC EVOLUTION; GALAXIES; LUMINOSITY; SATELLITES; STAR ACCRETION; STAR CLUSTERS; STAR EVOLUTION; STARS