Related papers: Missing in Action: New Physics and the Black Hole …
We model the dynamical structure of M87 (NGC4486) using high spatial resolution long-slit observations of stellar light in the central regions, two-dimensional stellar light kinematics out to half of the effective radius, and globular…
Recent observations support the idea that nuclear black holes grew by gas accretion while shining as luminous quasars at high redshift, and they establish a relation of the black hole mass with the host galaxy's spheroidal stellar system.…
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…
The LIGO-Virgo Collaboration has so far detected around 90 black holes, some of which have masses larger than what were expected from the collapse of stars. The mass distribution of LIGO-Virgo black holes appears to have a peak at…
Gravitational-wave measurements of the binary black hole population provide insights into the evolution of merging binaries. We explore potential correlation between mass and mass ratio with phenomenological population models where the…
Models for black hole (BH) formation from stellar evolution robustly predict the existence of a pair-instability supernova (PISN) mass gap in the range $\sim50$ to $\sim120$ solar masses. This theoretical prediction is supported by the…
We derive models of rotating very massive stellar cores with mass $\approx 10^2$--$10^4M_\odot$ which are marginally stable to the pair-unstable collapse, assuming that the core is isentropic and composed primarily of oxygen. It is shown…
Observations have shown that the majority of massive stars, progenitors of black holes (BHs), have on average more than one stellar companion. In triple systems, wide inner binaries can be driven to a merger by the third body due to…
Highly spinning Kerr black holes with masses $M = 1 - 100\ M_{\odot}$ are subject to an efficient superradiant instability in the presence of bosons with masses $\mu \sim 10^{-10} - 10^{-12}\ {\rm eV}$. We observe that this matches the…
Mergers of black-hole binaries are expected to release large amounts of energy in the form of gravitational radiation. However, binary evolution models predict merger rates too low to be of observational interest. In this paper we explore…
Recent numerical simulations of the fragmentation of primordial molecular clouds in hierarchical cosmogonies have suggested that the very first stars (the so-called Population III) may have been rather massive. Here we point out that a…
The majority of massive stars are found in close binaries which: (i) are prone to merge and (ii) are accompanied by another distant tertiary star (triples). Here, we study the evolution of the stellar post-merger binaries composed of the…
Rotational superradiance generates the amplification of incoming waves of sufficiently low frequency when scattered with a rotating absorbing body. This may be used to discover new \emph{bosonic} particles of mass $m_b$ if the rotating body…
The dynamics of galactic systems with central binary black holes is studied. The model is a modification from the restricted three body problem, in which a galactic potential is added as an external potential. Considering the case with an…
Regular black holes are generically unstable because of the classical phenomenon that goes by the name of "mass inflation" which destabilizes the inner horizon. In a recent article, [Phys.Rev.D~107~(2023)~2,~024005], it is argued that…
Recently (Brown \& Bethe 1994) it was suggested that most stars with main sequence mass in the range of about $18 - 30 M_{\odot}$ explode, returning matter to the Galaxy, and then go into low-mass ($\geq 1.5 M_{\odot}$) black holes. Even…
We propose the formation of massive pristine dark-matter (DM) halos with masses of $\sim 10^8~M_\odot$, due to the dynamical effects of frequent mergers in rare regions of the Universe with high baryonic streaming velocity relative to DM.…
Observations of elliptical galaxies suggest that black holes (BHs) might serve as dark energy candidates, coupled to the expansion of the Universe. According to this hypothesis, the mass of a BH could increase as the Universe expands. BH…
The runaway collision scenario is one of the most promising mechanisms to explain the formation of intermediate-mass black holes (IMBHs) in young dense star clusters. On the other hand, the massive stars that participate in the runaway…
If primordial black holes constitute the dark matter, stars forming in dark-matter dominated environments with low velocity dispersions, such as ultra-faint dwarf galaxies, may capture a black hole at birth. The capture probability is…