Related papers: Stellar Tidal Disruption Events by Direct Collapse…
Close encounters between neutron stars and main-sequence stars occur in globular clusters and may lead to various outcomes. Here we study encounters resulting in tidal disruption of the star. Using $N$-body models, we predict the typical…
We study tidal disruption events (TDEs) and compact object inspirals in nuclear star clusters (NSCs) hosting a central supermassive black hole (SMBH), focusing on their role in SMBH growth. Using the STARDISK version of the direct N-body…
The Direct Collapse Black Hole (DCBH) scenario provides a solution for forming the massive black holes powering bright quasars observed in the early Universe. A prerequisite for forming a DCBH is that the formation of (much less massive)…
Observational evidence suggests that the majority of stars may have been born in stellar clusters or associations. Within these dense environments, dynamical interactions lead to high rates of close stellar encounters. A variety of recent…
Nuclear star clusters (NSCs) and supermassive black holes (SMBHs) both inhabit galactic nuclei, coexisting in a range of bulge masses, but excluding each other in the largest or smallest galaxies. We propose that the transformation of NSCs…
The nature of the seeds of high-redshift supermassive black holes (SMBHs) is a key question in cosmology. Direct collapse black holes (DCBH) that form in pristine, atomic-line cooling halos, illuminated by a Lyman-Werner (LW) UV flux…
There has been suggestive evidence of intermediate-mass black holes (IMBHs; 10^{3-5} M_sun) existing in some globular clusters (GCs) and dwarf galaxies, but IMBHs as a population remain elusive. As a main-sequence star passes too close by…
An increasing number of ambiguous nuclear transients, including some extreme nuclear transients with very shallow light-curve declines and weak AGN activity in their host galaxies, have been reported. Stars form in or are captured by AGN…
The existence of black holes (BHs) of mass ~ 10^{9} M_sun at z > 6 is a big puzzle in astrophysics because even optimistic estimates of the accretion time are insufficient for stellar mass BHs of ~ 10 M_sun to grow into such supermassive…
Theoretical models predict that a population of Intermediate Mass Black Holes (IMBHs) of mass $M_\bullet \approx 10^{4-5} \, \mathrm{M_{\odot}}$ might form at high ($z > 10$) redshift by different processes. Such objects would represent the…
A bright flare from a galactic nucleus followed at late times by a $t^{-5/3}$ decay in luminosity is often considered the signature of the complete tidal disruption of a star by a massive black hole. The flare and power-law decay are…
Nuclear star clusters (NSCs), made up of a dense concentrations of stars and the compact objects they leave behind, are ubiquitous in the central regions of galaxies, surrounding the central supermassive black hole (SMBH). Close…
Dense stellar clusters surround the supermassive black holes (SMBH) in galactic nuclei. Interactions within the cluster can alter the stellar orbits, occasionally driving a star into the SMBH's tidal radius where it becomes ruptured, or…
Stars in the immediate vicinity of supermassive black holes (SMBHs) can be ripped apart by the tidal forces of the black hole. The subsequent accretion of the stellar material causes a spectacular flare of electromagnetic radiation. Here,…
In this paper we report results of collisional N-body simulations of the dynamical evolution of equal-mass star clusters containing a massive central black hole. Each cluster is composed of between 5,000 to 180,000 stars together with a…
A supermassive black hole can disrupt a star when its tidal field exceeds the star's self-gravity, and can directly capture stars that cross its event horizon. For black holes with mass M > 10^7 solar masses, tidal disruption of…
During the tidal disruption of a star by a massive black hole (BH) of mass MBH <~ 10^7 Msun, stellar debris falls back to the BH at a rate well above the Eddington rate. A fraction of this gas is subsequently blown away from the BH,…
Direct collapse black holes (DCBHs) are excellent candidates as seeds of supermassive black holes (SMBHs) observed at $z \gsim 6$. The formation of a DCBH requires a strong external radiation field to suppress $\rm H_2$ formation and…
We discuss the results of 3D simulations of tidal disruptions of white dwarfs by moderate-mass black holes as they may exist in the cores of globular clusters or dwarf galaxies. Our simulations follow self-consistently the hydrodynamic and…
Super-massive black holes (SMBHs) with $M_{\bullet} \sim 10^9 $ M$_{\odot}$ at $z>6$ likely originate from massive seed black holes (BHs). We investigate the consequences of seeding SMBHs with direct collapse BHs (DCBHs)…