What do observations tell us about the highest-redshift supermassive black holes?. (arXiv:2002.00972v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Trakhtenbrot_B/0/1/0/all/0/1">Benny Trakhtenbrot</a>
I review the current understanding of some key properties of the first
generation of growing supermassive black holes (SMBHs), as determined from the
most up-to-date observations. This includes their accretion rates and growth
history, their host galaxies, and the large-scale environments that enabled
their emergence less than a billion years after the Big Bang. The available
multi-wavelength data show that these SMBHs are consistent with
Eddington-limited, radiatively efficient accretion that had to proceed almost
continuously since very early epochs. ALMA observations of the hosts’ ISM
reveal gas-rich, well developed galaxies, with a wide range of SFRs that may
exceed ~1000 M_sol/yr. Moreover, ALMA uncovers a high fraction of companion,
interacting galaxies, on scales of <100 kpc. This supports the idea that the
first generation of high-mass, luminous SMBHs grew in over-dense environments,
and that major mergers may be important drivers for rapid SMBH and host galaxy
growth. Current X-ray surveys cannot access the lower-mass, supposedly more
abundant counterparts of these rare z>5 massive quasars, which should be able
to elucidate the earliest stages of BH formation and growth. Such lower-mass
nuclear BHs will be the prime targets of the deepest surveys foreseen for the
next generation of facilities and surveys, such as the upcoming Athena mission
and the Lynx mission concept.
I review the current understanding of some key properties of the first
generation of growing supermassive black holes (SMBHs), as determined from the
most up-to-date observations. This includes their accretion rates and growth
history, their host galaxies, and the large-scale environments that enabled
their emergence less than a billion years after the Big Bang. The available
multi-wavelength data show that these SMBHs are consistent with
Eddington-limited, radiatively efficient accretion that had to proceed almost
continuously since very early epochs. ALMA observations of the hosts’ ISM
reveal gas-rich, well developed galaxies, with a wide range of SFRs that may
exceed ~1000 M_sol/yr. Moreover, ALMA uncovers a high fraction of companion,
interacting galaxies, on scales of <100 kpc. This supports the idea that the
first generation of high-mass, luminous SMBHs grew in over-dense environments,
and that major mergers may be important drivers for rapid SMBH and host galaxy
growth. Current X-ray surveys cannot access the lower-mass, supposedly more
abundant counterparts of these rare z>5 massive quasars, which should be able
to elucidate the earliest stages of BH formation and growth. Such lower-mass
nuclear BHs will be the prime targets of the deepest surveys foreseen for the
next generation of facilities and surveys, such as the upcoming Athena mission
and the Lynx mission concept.
http://arxiv.org/icons/sfx.gif
