Deep spectroscopy of the MV ~-14.8 host galaxy of a tidal disruption flare in A1795

W. P. Maksym*, M. P. Ulmer, K. C. Roth, J. A. Irwin, R. Dupke, L. C. Ho, W. C. Keel, C. Adami

*Corresponding author for this work

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

A likely tidal disruption of a star by the intermediate-mass black hole (IMBH) of a dwarf galaxy was recently identified in association with Abell 1795. Without deep spectroscopy for this very faint object, however, the possibility of a more massive background galaxy or even a disc-instability flare from a weak active galactic nucleus (AGN) could not be dismissed. We have now obtained 8 h of Gemini spectroscopy which unambiguously demonstrates that the host galaxy is indeed an extremely low mass (Mz.ast; ~ 3 × 108M) galaxy in Abell 1795, comparable to the least massive galaxies determined to host IMBHs via other studies. We find that the spectrum is consistent with the X-ray flare being due to a tidal disruption event rather than an AGN flare.We also set improved limits on the black hole mass (log[M/M] ~ 5.3-5.7) and infer a 15 yr X-ray variability of a factor of ≥104. The confirmation of this galaxy-black hole system provides a glimpse into a population of galaxies that is otherwise difficult to study, due to the galaxies' low masses and intrinsic faintness, but which may be important contributors to the tidal disruption rate.

Original languageEnglish (US)
Pages (from-to)866-873
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume444
Issue number1
DOIs
StatePublished - Jul 26 2014

Keywords

  • Galaxies: clusters: individual: Abell 1795
  • Galaxies: distances and redshifts
  • Galaxies: dwarf
  • Galaxies: kinematics and dynamics
  • Galaxies: nuclei
  • X-rays: bursts

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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