Related papers: Dark Black Holes in the Mass Gap
Black holes below Chandrasekhar mass limit (1.4 $M_{\odot}$) can not be produced via any standard stellar evolution. Recently, gravitational wave experiments have also discovered unusually low mass black holes whose origin is yet to be…
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…
We investigate the hypothesis that the cores of elliptical galaxies and bulges are created from the binding energy liberated by the coalescence of supermassive binary black holes during galaxy mergers. Assuming that the central density…
The predicted rate of binary black hole mergers from galactic fields can vary over several orders of magnitude and is extremely sensitive to the assumptions of stellar evolution. But in dense stellar environments such as globular clusters,…
We study the impact of stellar cooling due to light axion emission on the formation and evolution of black hole binaries, via stable mass transfer and the common envelope scenario. We find that in the presence of light axion emission, no…
We present direct N-body simulations, carried out with Nbody6++GPU, of young and compact low metallicity star clusters with $1.1\times 10^5$ stars, a velocity dispersion of $\sim$ 10 $\mathrm{km\,s^{-1}}$, a half mass radius $R_h=0.6$ pc,…
Ninety gravitational wave events have been detected by the LIGO-Virgo-KAGRA network and are released in the Gravitational-Wave Transient Catalog. Among these events, 83 cases are definitely binary black hole mergers since the masses of all…
Although stable neutron stars (NS) can in principle exist down to masses Mns ~ 0.1Msun, standard models of stellar core-collapse predict a robust lower limit Mns >~ 1.2Msun, roughly commensurate with the Chandrasekhar mass Mch of the…
The evolution of dense star clusters is followed by direct high-accuracy N-body simulation. The problem is to first order a gravitational N-body problem, but stars evolve due to astrophysics and the more massive ones form black holes or…
Galaxies with Milky Way-like stellar masses have a wide range of bulge and black hole masses; in turn, these correlate with other properties such as star formation history. While many processes may drive bulge formation, major and minor…
The possible Fermi detection of an electromagnetic counterpart to the double black hole merger GW150914 has inspired many theoretical models, some of which propose that the holes spiraled together inside a massive star. However, we show…
The first LIGO-Virgo detections have confirmed the existence of massive black holes (BHs), with mass $30-40$ M$_\odot$. Such BHs might originate from massive metal-poor stars ($Z<0.3$ Z$_\odot$) or from gravitational instabilities in the…
Close encounters and physical collisions between stars in young dense clusters can result in new channels for stellar evolution, and may lead to the formation of very massive stars and black holes via runaway merging. We present some…
Primordial black holes may encode the conditions of the early universe, and may even constitute a significant fraction of cosmological dark matter. Their existence has yet to be established. However, black holes with masses below…
The discovery of gravitational waves from compact objects coalescence opens a brand-new window to observe the universe. With more events being detected in the future, statistical examinations would be essential to better understand the…
In recent years, the existence of a gap in the mass spectrum of compact objects formed from stellar collapse, between the heaviest neutron stars and the lightest black holes, has been a matter of significant debate. The presence or absence…
We introduce a novel black hole mass function which realistically models the physics of star formation and pair instability supernova with a minimal number of parameters. Applying this to all events in the LIGO-Virgo GWTC-2 catalog, we…
The detection of the binary black hole merger GW190521, with primary black hole mass $85^{+21}_{-14}$ ${\rm M}_{\odot}$, proved the existence of black holes in the theoretically predicted pair-instability gap ($\sim60-120 \, {\rm…
At the end of its life, a very massive star is expected to collapse into a black hole. The recent detection of an 85 Msun black hole from the gravitational wave event GW 190521 appears to present a fundamental problem as to how such heavy…
Stars with an initial mass more than ~25 Msun are thought to ultimately become black holes. Then stellar-mass black holes should be ubiquitous but fewer than 20 have been found in our Galaxy to date, all of which have been found through…