Related papers: Formation pathway of Population III coalescing bin…
Dense stellar clusters are expected to house the ideal conditions for binary black hole (BBH) formation, both through binary stellar evolution and through dynamical encounters. We use theoretical arguments as well as $N$-body simulations to…
The James Webb Space Telescope (JWST) has revealed a population of active galactic nuclei (AGNs) that challenge existing black hole (BH) formation models. These newly observed BHs seem overmassive compared to the host galaxies and have an…
GW190521 is a merger of two black holes (BHs), wherein at least one BH lies within the pair-instability (PI) mass gap, and it is difficult to form because of the effects of PI supernovae (PISNe) and pulsational PI (PPI). In this study, we…
Understanding binary black hole (BBH) dynamics in dense star clusters is key to interpreting the gravitational wave detections by LIGO and Virgo. Here, we perform $N$-body simulations of star clusters, focusing on BBH formation mechanisms,…
In the case of zero-metal (population III or Pop III) stars, we show that the total mass of binary black holes from binary Pop III star evolution can be $\sim 150 \,M_{\odot}$, which agrees with the mass of the binary black hole GW190521…
I investigate the roles of cluster dynamics and massive binary evolution in producing stellar-remnant binary black hole (BBH) mergers over the cosmic time. To that end, dynamical BBH mergers are obtained from long-term direct N-body…
Black hole (BH) binary mergers formed through dynamical interactions in dense star clusters are believed to be one of the main sources of gravitational waves for Advanced LIGO and Virgo. Here we present a fast numerical method for…
Pair instability (PI) and pulsational PI prevent the formation of black holes (BHs) with mass $\gtrsim{}60$ M$_\odot$ from single star evolution. Here, we investigate the possibility that BHs with mass in the PI gap form via stellar mergers…
The connection between the binary black hole (BBH) mergers observed by LIGO-Virgo-KAGRA (LVK) and their stellar progenitors remains uncertain. Specifically, the fraction $\epsilon$ of stellar mass that ends up in BBH mergers and the delay…
We investigate properties of black hole (BH) binaries formed in globular clusters via dynamical processes, using direct N-body simulations. We pay attention to effects of BH mass function on the total mass and mass ratio distributions of BH…
We perform population synthesis simulations for Population III (Pop III) coalescing binary neutron stars (NS-NSs), neutron star - black hole binaries (NS-BHs), and binary black holes (BH-BHs) which merge within the age of the universe. We…
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…
We use N-body simulations to study the dynamical evolution of Population III (Pop III) stellar systems and the resulting binary statistics. We design a physically-motivated framework for the initial conditions of Pop III star clusters,…
The formation process of Population III (PopIII) stars in the mass accretion phase is investigated by numerical experiments. The barotropic relation of primordial gas and artificial stiffening of the equation of state in very dense regions…
These are exciting times for binary black hole (BBH) research. LIGO and Virgo detections are progressively drawing a spectacular fresco of BBH masses, spins and merger rates. In this review, we discuss the main formation channels of BBHs…
Evolution of first population of massive metal-free binary stars is followed. Due to the low metallicity, the stars are allowed to form with large initial masses and to evolve without significant mass loss. Evolution at zero metallicity,…
The detection of over a hundred gravitational wave signals from double compacts objects have confirmed the existence of such binaries with tight orbits. Two main formation channels are generally considered to explain the formation of these…
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…
After the nearly hundred gravitational-wave detections reported by the LIGO-Virgo-KAGRA Collaboration, the question of the cosmological origin of merging binary black holes (BBHs) remains open. The two main formation channels generally…
Massive close binary stars with extremely small separations have been observed, and they are possible progenitors of gravitational-wave sources. The evolution of massive binaries in the protostellar accretion stage is key to understanding…