Related papers: Stellar Tidal Disruption Events by Direct Collapse…
We find that convective regions of collapsing massive stellar cores possess sufficient stochastic angular momentum to form intermittent accretion disks around the newly born neutron star (NS) or black hole (BH), as required by the…
Tidal Disruption Events (TDEs) are routinely observed in quiescent galaxies, as stars from the nuclear star cluster are scattered into the loss cone of the central supermassive black hole (SMBH). TDEs are also expected to occur in Active…
We estimate the rate at which stars are captured by supermassive black holes (BHs) in the centres of bulges and elliptical galaxies assuming that these initially had an isothermal cusp (rho ~ r^{-2} with velocity dispersion sigma_*). If…
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…
Massive black holes (BHs) at the centres of massive galaxies are ubiquitous. The population of BHs within dwarf galaxies, on the other hand, is evasive. Dwarf galaxies are thought to harbour BHs with proportionally small masses, including…
We have used high-resolution zoom-in simulations of direct collapse to supermassive black hole (SMBH) seeds within dark mater (DM) halos in the presence of magnetic fields generated during the collapse, down to $10^{-5}$ pc or 2 AU. We…
Theoretical modeling of massive stars predicts a gap in the black hole (BH) mass function above $\sim 40-50\,M_{\odot}$ for BHs formed through single star evolution, arising from (pulsational) pair-instability supernovae. However, in dense…
Tidal disruption events (TDEs) are among the brightest transients in the optical, ultraviolet, and X-ray sky. These flares are set into motion when a star is torn apart by the tidal field of a massive black hole, triggering a chain of…
Tidal disruption events (TDEs) occur when a star crosses the tidal radius of a black hole (BH) and is ripped apart, providing a powerful way to probe dormant BHs over a wide mass range. In this study, we present our late-time observations…
The direct collapse black hole (DCBH) scenario describes the isothermal collapse of a pristine gas cloud directly into a massive, M_BH=10^4-10^6 M_sun black hole. In this paper we show that large HI column densities of primordial gas at…
Binary black holes (BBHs) appear to be widespread and are able to merge through the emission of gravitational waves, as recently illustrated by LIGO. The spin of the BBHs is one of the parameters that LIGO can infer from the gravitational…
Stars approaching supermassive black holes (SMBHs) in the centers of galaxies can be torn apart by strong tidal forces. We study the physics of tidal disruption by a binary SMBH as a function of the binary mass ratio $q = M_2 / M_1$ and…
We study the formation of massive black holes in the first star clusters. We first locate star-forming gas clouds in proto-galactic haloes of $\gtrsim \!10^7\,{\rm M}_{\odot}$ in cosmological hydrodynamics simulations and use them to…
Massive stellar clumps in high redshift galaxies interact and migrate to the center to form a bulge and exponential disk in <1 Gyr. Here we consider the fate of intermediate mass black holes (BHs) that might form by massive-star coalescence…
Suggestive evidence has accumulated that intermediate mass black holes (IMBH) exist in some globular clusters. As stars diffuse in the cluster, some will inevitable wander sufficiently close to the hole that they suffer tidal disruption. An…
Observed active galactic nuclei at redshifts $\gtrsim 6$ suggest that supermassive black holes (SMBHs) had formed early on. Accretion of matter onto remnants of Population III stars leading to SMBHs is a very slow process, and therefore,…
We investigate the impact of massive primordial black holes (PBHs; $m_{\rm BH}\sim 10^6~M_{\odot}$) on the star formation and first galaxy assembly process using high-resolution hydrodynamical simulations from $z = 1100$ to $z \sim 9$. We…
The dynamical assembly of binary black holes (BBHs) in dense star clusters (SCs) is one of the most promising pathways for producing observable gravitational wave (GW) sources, however several other formation scenarios likely operate as…
We propose that one of the sources in the recently detected system CR7 by Sobral et al. (2015) through spectro-photometric measurements at $z = 6.6$ harbors a direct collapse blackhole (DCBH). We argue that the LW radiation field required…
Supermassive black holes (BHs) of millions solar masses and above reside in the center of most local galaxies, but they also power active galactic nuclei and quasars, detected up to z=7. This observational evidence puts strong constraints…