The host galaxies of z=7 quasars: predictions from the BlueTides simulation. (arXiv:1912.03428v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Marshall_M/0/1/0/all/0/1">Madeline A. Marshall</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ni_Y/0/1/0/all/0/1">Yueying Ni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matteo_T/0/1/0/all/0/1">Tiziana Di Matteo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wyithe_J/0/1/0/all/0/1">J. Stuart B. Wyithe</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wilkins_S/0/1/0/all/0/1">Stephen Wilkins</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Croft_R/0/1/0/all/0/1">Rupert A.C. Croft</a>
We examine the properties of the host galaxies of $z=7$ quasars using the
large volume, cosmological hydrodynamical simulation BlueTides. We find that
the most massive black holes and quasars are hosted by massive galaxies with
stellar masses $log(M_ast/M_odot)=10.8pm0.2$, and $10.2pm0.4$, which have
a wide range of star formation rates, of $50substack{+119 \
-35}M_odot/rm{yr}$ and $19substack{+28 \ -12}M_odot/rm{yr}$,
respectively. The hosts of the most massive black holes and quasars in
BlueTides are generally bulge-dominated, with bulge-to-total mass ratio
$B/Tsimeq0.85pm0.1$, however their morphologies are not biased relative to
the overall $z=7$ galaxy sample. We find that the hosts of the most massive
black holes and quasars are significantly more compact, with half-mass radii
$R_{0.5}=0.29substack{+0.15 \ -0.10}$ kpc and $0.28substack{+0.08 \ -0.06}$
kpc respectively, relative to galaxies with similar masses, which have
$R_{0.5}=0.5substack{+0.3 \ -0.2}$ kpc. We make mock James Webb Space
Telescope (JWST) images of these quasars and their host galaxies. We find that
distinguishing the host from the quasar emission will be possible but still
challenging with JWST, due to the small sizes of quasar hosts. We find that
currently observable quasar samples are biased tracers of the intrinsic black
hole–stellar mass relations, following a relation that is 0.27 dex higher than
that of the full galaxy sample. Finally, we find that black hole hosts are
generally quite isolated. However, the most massive black holes are more likely
to be found in denser environments than the typical
$M_{textrm{BH}}>10^{6.5}M_odot$ black hole, indicating that minor mergers at
least play some role in growing black holes in the early Universe.
We examine the properties of the host galaxies of $z=7$ quasars using the
large volume, cosmological hydrodynamical simulation BlueTides. We find that
the most massive black holes and quasars are hosted by massive galaxies with
stellar masses $log(M_ast/M_odot)=10.8pm0.2$, and $10.2pm0.4$, which have
a wide range of star formation rates, of $50substack{+119 \
-35}M_odot/rm{yr}$ and $19substack{+28 \ -12}M_odot/rm{yr}$,
respectively. The hosts of the most massive black holes and quasars in
BlueTides are generally bulge-dominated, with bulge-to-total mass ratio
$B/Tsimeq0.85pm0.1$, however their morphologies are not biased relative to
the overall $z=7$ galaxy sample. We find that the hosts of the most massive
black holes and quasars are significantly more compact, with half-mass radii
$R_{0.5}=0.29substack{+0.15 \ -0.10}$ kpc and $0.28substack{+0.08 \ -0.06}$
kpc respectively, relative to galaxies with similar masses, which have
$R_{0.5}=0.5substack{+0.3 \ -0.2}$ kpc. We make mock James Webb Space
Telescope (JWST) images of these quasars and their host galaxies. We find that
distinguishing the host from the quasar emission will be possible but still
challenging with JWST, due to the small sizes of quasar hosts. We find that
currently observable quasar samples are biased tracers of the intrinsic black
hole–stellar mass relations, following a relation that is 0.27 dex higher than
that of the full galaxy sample. Finally, we find that black hole hosts are
generally quite isolated. However, the most massive black holes are more likely
to be found in denser environments than the typical
$M_{textrm{BH}}>10^{6.5}M_odot$ black hole, indicating that minor mergers at
least play some role in growing black holes in the early Universe.
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