Related papers: A search for the first massive galaxy clusters
A brief overview on the current status of the census of the early universe population is given. Observational surveys of high redshift galaxies provide direct opportunities to witness the cosmic dawn and to have better understanding of how…
In cosmological models favored by current observations, the first astrophysical objects formed in dark matter halos at redshifts starting at z>20, and their properties were determined by primordial H_2 molecular chemistry. These…
The most frequently proposed model for the origin of quasars holds that the high accretion rates seen in luminous active galactic nuclei are primarily triggered during major mergers between gas-rich galaxies. While plausible for decades,…
The cosmic reionization era, which includes formation of the first stars, galaxies, and AGN, is now one of the most active frontiers of cosmological research. We review briefly our current understanding of the early structure formation, and…
High-redshift quasars ($z\gtrsim6$), powered by black holes (BHs) with large inferred masses, imply rapid BH growth in the early Universe. The most extreme examples have inferred masses of $\sim \! 10^9\,$M$_\odot$ at $z = 7.5$ and $\sim \!…
We investigate the formation of the first massive black holes in high redshift galaxies, with the goal of providing insights to which galaxies do or do not host massive black holes. We adopt a novel approach to forming seed black holes in…
The first stars in the universe, forming at redshifts z>15 in minihalos with masses of order 10^6 Msun, may leave behind black holes as their remnants. These objects could conceivably serve as "seeds" for much larger black holes observed at…
One of the most prominent features of galaxy clusters is the presence of a dominant population of massive ellipticals in their cores. Stellar archaeology suggests that these gigantic beasts assembled most of their stars in the early…
High redshift quasars emit copious X-ray photons which heat the intergalactic medium to temperatures up to $\sim$ 10$^6$ K. At such high temperatures the primordial gas will not form stars until it is assembled into dark matter haloes with…
Obscured or narrow-line active galaxies offer an unobstructed view of the quasar environment in the presence of a luminous and vigorously accreting black hole. We exploit the large new sample of optically selected luminous narrow-line…
The existence of high-$z$ over-massive supermassive black holes represents a major conundrum in our understanding of black hole evolution. In this paper, we probe from the observational point of view how early Universe environmental…
The origin of supermassive black holes is an open question that has been explored considering gas- and collision-based formation channels to explain the high number of quasars observed in the early Universe. According to numerical…
Exceptionally bright quasars with redshifts up to z=6.28 have recently been discovered. Quasars are thought to be powered by the accretion of gas onto supermassive black holes at the centres of galaxies. Their maximum (Eddington) luminosity…
The properties of the first generation of black-hole seeds trace and distinguish different models of formation of cosmic structure in the high-redshift universe. The observational challenge lies in identifying black holes in the mass range…
Models and observations suggest that luminous quasar activity is triggered by mergers, so it should preferentially occur in the most massive primordial dark matter haloes, where the frequency of mergers is expected to be the highest. Since…
The standard cold dark matter plus cosmological constant model predicts that galaxies form within dark-matter haloes, and that low-mass galaxies are more dark-matter dominated than massive ones. The unexpected discovery of two low-mass…
Next generation CMB experiments with arcmin resolution will, for free, lay the foundations for a real breakthrough on the study of the early evolution of galaxies and galaxy clusters, thanks to the detection of large samples of strongly…
It has been suggested that the supermassive black holes, at the centers of galaxies and quasars, may initially form in single collapses of relativistic star clusters or supermassive stars built-up during the evolution of dense star…
With the help of a statistical parameter derived from optical spectra, we show that the current star formation rate of a galaxy, falling into a cluster along a supercluster filament, is likely to undergo a sudden enhancement before the…
We review the steps which have led to the discovery of a widespread population of objects at z = 3 with many of the characteristics which we expect for primeval galaxies, and emphasize in particular the advantages of a colour selection…