Expected intermediate mass black holes in the Virgo cluster. II. Late-type galaxies. (arXiv:1811.03232v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Graham_A/0/1/0/all/0/1">Alister W. Graham</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Soria_R/0/1/0/all/0/1">Roberto Soria</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Davis_B/0/1/0/all/0/1">Benjamin L. Davis</a>
The Chandra X-ray Observatory’s Cycle 18 Large Program titled “Spiral The Chandra X-ray Observatory’s Cycle 18 Large Program titled “Spiral http://arxiv.org/icons/sfx.gif
galaxies of the Virgo Cluster” will image 52 galaxies with the ACIS-S detector.
Combined with archival data for an additional 22 galaxies, this will represent
the complete sample of 74 spiral galaxies in the Virgo cluster with
star-formation rates $gtrsim$ 0.3 $M_{odot}$/yr. Many of these galaxies are
expected to have an active nucleus, signalling the presence of a central black
hole. In preparation for this survey, we predict the central black hole masses
using the latest black hole scaling relations based on spiral arm pitch angle
$phi$, velocity dispersion $sigma$, and total stellar mass $M_{rm
*,galaxy}$. With a focus on intermediate mass black holes ($10^2
galaxies of the Virgo Cluster” will image 52 galaxies with the ACIS-S detector.
Combined with archival data for an additional 22 galaxies, this will represent
the complete sample of 74 spiral galaxies in the Virgo cluster with
star-formation rates $gtrsim$ 0.3 $M_{odot}$/yr. Many of these galaxies are
expected to have an active nucleus, signalling the presence of a central black
hole. In preparation for this survey, we predict the central black hole masses
using the latest black hole scaling relations based on spiral arm pitch angle
$phi$, velocity dispersion $sigma$, and total stellar mass $M_{rm
*,galaxy}$. With a focus on intermediate mass black holes ($10^2<M_{rm
bh}/M_{odot}<10^5$), we highlight NGC 4713 and NGC 4178, both with $M_{rm
bh}approx10^3$-$10^4$ (an estimate which is further supported in NGC 4718 by
its nuclear star cluster mass). From Chandra archival data, we find that both
galaxies have a point-like nuclear X-ray source, with unabsorbed 0.3-10 keV
luminosities of a few times 10$^{38}$ erg/s. In NGC 4178, the nuclear source
has a soft, probably thermal, spectrum consistent with a stellar-mass black
hole in the high/soft state, while no strong constraints can be derived for the
nuclear emission of NGC 4713. In total, 33 of the 74 galaxies are predicted to
have $M_{rm bh}<(10^5$-$10^6)$ $M_{odot}$, and several are consistently
predicted, via three methods, to have masses of $10^4$-$10^5,M_{odot}$, such
as IC 3392, NGC 4294 and NGC 4413. We speculate that a sizeable population of
IMBHs may reside in late-type spiral galaxies with low stellar mass ($M_{rm
*,galaxy}lesssim10^{10},M_{odot}$).
