Related papers: Formation of mass gap compact object and black hol…
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…
Mass distribution of black holes identified through X-ray emission suggests a paucity of black holes in the mass range of 3 to 5 solar masses. Modified theories have been devised to explain this mass gap, and it is suggested that natal…
We investigate the formation of merging binary black holes (BHs) through isolated binary evolution, performing binary population synthesis calculations covering an unprecedentedly wide metallicity range of Population (Pop) I, II, III, and…
We study the contribution of binary black hole (BH-BH) mergers from the first, metal-free stars in the Universe (Pop III) to gravitational wave detection rates. Our study combines initial conditions for the formation of Pop III stars based…
We briefly discuss a possible cosmological implication of the observed binary black hole mergings detected by LIGO-Virgo-Kagra collaboration (GWTC-3 catalogue) for the primordial black hole (PBH) formation in the early Universe. We show…
With the release of the fourth LIGO--Virgo--KAGRA gravitational-wave catalog (GWTC-4), we are starting to gain a detailed view of the population of merging binary black holes. The formation channels of these black holes is not clearly…
We present the merger rate density of Population (Pop.) III binary black holes (BHs) by means of a widely-used binary population synthesis code BSE with extensions to very massive and extreme metal-poor stars. We consider not only low-mass…
Population III (Pop. III) binary stars likely produced the first stellar-born binary black hole (BBH) mergers in the Universe. Here, we quantify the main sources of uncertainty for the merger rate density evolution and mass spectrum of Pop.…
We present the first numerical simulations of an initially non-spinning black-hole binary with mass ratio as large as 10:1 in full general relativity. The binary completes approximately 3 orbits prior to merger and radiates about 0.415% of…
In the population synthesis simulations of Pop III stars, many BH (Black Hole)-BH binaries with merger time less than the age of the Universe $(\tau_{\rm H})$ are formed, while NS (Neutron Star)-BH binaries are not. The reason is that Pop…
GW231123 is a merger of two black holes (BHs) with estimated masses exceeding $100\;{\rm M}_{\odot}$, making them the most massive BHs discovered to date via gravitational wave (GW) observations. We investigate whether GW231123-like events…
The LIGO/Virgo Collaboration (LVC) recently reported the detection of GW190814, a merger of a $23^{+1.0}_{-0.9}~M_{\odot}$ primary black hole (BH), and a $2.6^{+0.08}_{-0.08}~M_{\odot}$ secondary. The secondary's mass falls into the…
With the growing number of detections of binary black hole mergers, we are beginning to probe structure in the distribution of masses. A recent study by Schneider et al. proposes that isolated binary evolution of stripped stars naturally…
We have analyzed the observed radial-velocity curve for the X-ray binary M33 X-7 in a Roche model. We have analyzed the dependence between the component masses and the degree of filling of the optical star's Roche lobe to obtain the ratio…
We focus on gravitational-wave events of binary black-hole mergers up to the third observing run with the minimum false alarm rate smaller than $10^{-5}\,{\rm yr}^{-1}$. These events tell us that the mass ratio of two black holes follows…
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 X-ray binaries indicate a dearth of compact objects in the mass range from $\sim 2-5 M_{\odot}$. The existence of this (first mass) gap has been used to discriminate between proposed engines behind core-collapse supernovae.…
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…
In order to investigate the formation rate of binary black holes (BBHs) in stellar clusters with a mass comparable to open clusters, we performed a series of direct $N$-body simulations of open clusters with a mass of $2.5\times10^3$ (Model…
The mass range of observed black holes extends from stellar-mass to supermassive scales, yet the existence of objects in the intermediate-mass range of $10^{2} - 10^{5} \text{M}_{\odot}$ remains unconfirmed. Black holes are suspected to…