Related papers: Massive black hole seeds from low angular momentum…
There is compelling evidence that supermassive black holes (SMBHs) exist. Yet the origin of these objects, or their seeds, is still unknown. We are performing general relativistic simulations of gravitational collapse to black holes in…
Supermassive black holes (SMBHs) of 10^9-10^10 Msun were already in place ~13 Gyr ago, at z>6. Super-Eddington growth of low-mass BH seeds (~100 Msun) or less extreme accretion onto ~10^5 Msun seeds have been recently considered as the main…
The supermassive black holes (SMBHs) massive enough to power the bright redshift ~6 quasars observed in the Sloan Digital Sky Survey (SDSS) are thought to have assembled by mergers and/or gas accretion from less massive "seed" BHs. If the…
The early Universe was composed almost entirely of hydrogen and helium, with only trace amounts of heavy elements. It was only after the first generation of star formation that the Universe became sufficiently polluted to produce a second…
Supermassive black hole (SMBH) growth plausibly occurs via runaway astrophysical black hole mergers in nuclear star clusters that form intermediate mass black hole seeds at high redshifts. Such a model yields an order-of-magnitude higher…
We investigate the physical conditions for the growth of intermediate mass seed black holes assumed to have formed from remnants of the first generation of massive stars. We follow the collapse of high-sigma halos with Tvir > 1e4 K using…
Observations with the James Webb Space Telescope (JWST) have identified an abundant population of supermassive black holes (SMBHs) already in place during the first few hundred million years of cosmic history. Most of them appear…
The existence of supermassive black holes (SMBHs) with masses greater than $\sim 10^{9}M_{\odot}$ at high redshift ($z\gtrsim 7$) is difficult to accommodate in standard astrophysical scenarios. We study the possibility that (nearly)…
We study the early stage of the formation of seed supermassive black holes via direct collapse in dark matter (DM) halos, in the cosmological context. We perform high-resolution zoom-in simulations of such collapse at high-$z$. Using the…
Recent observations of quasars powered by supermassive black holes (SMBHs) out to z > 7 constrain both the initial seed masses and the growth of the most massive black holes (BHs) in the early universe. Here we elucidate the implications of…
Massive black holes (BHs) inhabit local galaxies, including the Milky Way and some dwarf galaxies. BH formation, occurring at early cosmic times, must account for the properties of BHs in today's galaxies, notably why some galaxies host a…
Most cosmological simulations of galaxy evolution include active galactic nucleus (AGN) feedback, typically seeding black holes with masses of $\geq 10^5\, h^{-1}\, \rm{M}_{\odot}$ when the dark matter halo exceeds a given threshold mass.…
Quasars observed at redshifts $z\sim 6-7.5$ are powered by supermassive black holes which are too large to have grown from early stellar remnants without efficient super-Eddington accretion. A proposal for alleviating this tension is for…
The correlation between the mass of supermassive black holes in galaxy nuclei and the mass of the galaxy spheroids or bulges (or more precisely their central velocity dispersion), suggests a common formation scenario for galaxies and their…
Supermassive stars, with masses greater than a million solar masses, are possible progenitors of supermassive black holes in galactic nuclei. Because of their short nuclear burning timescales, such objects can be formed only when matter is…
The discovery of supermassive black holes with masses $\gtrsim 10^9 M_\odot$ at redshifts $z\gtrsim 10$ challenges conventional formation scenarios based on baryonic accretion and mergers within the first few hundred million years. We…
We argue that the stable (color singlet) supermassive gravitinos proposed in our previous work can serve as seeds for giant primordial black holes. These seeds are hypothesized to start out as tightly bound states of fractionally charged…
We study the supermassive black holes (SMBHs) observed in the galactic centers. Although the origin of SMBHs has not been well understood yet, previous studies suggest that seed black holes (BHs) with masses $10^{4-5}M_\odot$ exist at a…
In this white paper we explore the capabilities required to identify and study supermassive black holes formed from heavy seeds ($\mathrm{M_{\bullet}} \sim 10^4 - 10^6 \, \mathrm{M_{\odot}}$) in the early Universe. To obtain an unequivocal…
Observations of high-redshift quasars indicate that super massive black holes (SMBHs) with masses greater than ${\sim}10^9~M_\odot$ were assembled within the first billion years after the Big Bang. It is unclear how such massive black holes…