Dr Roberto Decarli, Istituto Nazionale di Astrofisica (INAF), Bologna Since their first discovery about 60 years ago, quasars have been
at the forefront of our understanding of the distant universe. We now
know >400 quasars at redshift z>6, when the Universe was < 1 Gyr old.
Their mere presence poses a challenge to models of the formation and
early growth not only of their massive black holes, but also of their
host galaxies, their dust content, and the large-scale structures where
they reside. In the last few years, however, we have witnessed
transformational leaps in our understanding of the properties of early
quasars, thanks to unprecedented observational achievements, in
particular with ALMA and JWST. We have now accurate black hole mass
estimates in quasars up to z~7.6; we have mapped the gas and dust
distribution in the quasar host galaxies down to 100 pc resolution, and
quantified their star formation rate, metallicity, and other properties
(gas density, photoionization conditions, etc); and we have secured a
census of tens of spectroscopically-confirmed galaxies in the
environment of quasars at z>6. These observational results allow us to
sketch a novel picture on the formation of some of the most massive
astrophysical sources in the early Universe.
Those unable to attend the colloquium in person are invited to participate online through Zoom (Meeting ID: 942 0262 2849, passcode 792771) using the link: https://eu02web.zoom-x.de/j/94202622849?pwd=dGlPQXBiUytzY1M2UE5oUDRhbzNOZz09
Dr Decarli is available for meetings by arrangement with his host, Kathryn Kreckel (kathryn.kreckel@uni-heidelberg.de)
