Deep Spectroscopy of the $M_Vsim -14.8$ Host Galaxy of a Tidal Disruption Flare in A1795

Kavli Affiliate: Luis Ho

| First 5 Authors: W. Peter Maksym, Melville Ulmer, Kathy Roth, Jimmy Irwin, Renato Dupke

| Summary:

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 disk-instability
flare from a weak AGN could not be dismissed. We have now obtained 8 hours of
Gemini spectroscopy which unambiguously demonstrate that the host galaxy is
indeed an extremely low-mass $(M_astsim 3times 10^8; {rm M}_{odot})$
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 $({rm log}[M_{bullet}/{rm
M}_{odot}] sim 5.3 – 5.7)$ and infer a 15-year X-ray variability of a factor
of $> 10^4$. 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.

| Search Query: ArXiv Query: search_query=au:”Luis Ho”&id_list=&start=0&max_results=10

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