相关论文: Low Mass Naked Singularities from Dark Core Collap…
A sub-solar mass primordial black hole (PBH) passing through a neutron star, can lose enough energy through interactions with the dense stellar medium to become gravitationally bound to the star. Once captured, the PBH would sink to the…
In a certain class of scalar-Gauss-Bonnet gravity, the black holes and the neutron stars can undergo spontaneous scalarization -- a strong gravity phase transition triggered by a tachyonic instability due to the nonminimal coupling between…
We analyze the early growth stage of direct-collapse black holes (DCBHs) with $\sim 10^{5} \ \rm M_\odot$, which are formed by collapse of supermassive stars in atomic-cooling halos at $z \gtrsim 10$. A nuclear accretion disk around a…
Direct collapse within dark matter (DM) halos is a promising path to form supermassive black hole (SMBH) seeds at high redshifts. The outer part of this collapse remains optically thin, and has been studied intensively using numerical…
Hypermassive neutron stars (HMNSs) -- equilibrium configurations supported against collapse by rapid differential rotation -- are possible transient remnants of binary neutron star mergers. Using newly developed codes for…
Several observations suggest the existence of super-massive black holes (SMBH) at the centers of giant galaxies. However the mechanism under which these objects form remains non completely understood. In this work we review an alternative…
Black hole - neutron star $(BH/NS)$ binaries are of interest in many ways: they are intrinsically multi-messenger systems, highly transient, radiate gravitational waves detectable by LIGO, and may produce $\gamma$-ray bursts. Although it…
The core collapse of a massive star results in the formation of a proto-neutron star (PNS). If enough material is accreted onto a PNS it will become gravitationally unstable and further collapse into a black-hole (BH). We perform a…
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.…
Dark matter (DM) may be captured around a neutron star (NS) through DM-nucleon interactions. We observe that the enhancement of such capturing is particularly significant when the DM velocity and/or momentum transfer depend on the…
The dynamical processes involving stellar-remnant black holes (BH) in stellar clusters has always drawn attention due to the BHs' potential in a number of astrophysical phenomena, especially the dynamical formation of binary black holes…
JWST reveals numerous high-z galaxies and Supermassive Black Holes (SMBHs), suggesting that stars and SMBH seeds formation at $z \gtrsim 10$ may be more efficient than previously derived. One popular SMBH seed scenario is the Direct…
Can a naked singularity (NkS) be distinguished from a black hole (BH)? We have investigated it with cutting-edge general relativistic magneto-hydrodynamic (GRMHD) simulations, followed by general relativistic radiation transfer (GRRT)…
Recently, the possibility was pointed out by one of the present authors and his collaborators that an effective naked singularity referred to as "a visible border of spacetime" is generated by high-energy particle collision in the context…
We simulate the formation of Fuzzy Dark Matter (FDM) cores in the presence of a Black Hole (BH) to explore whether BHs can serve as seeds for FDM core condensation. Our analysis is based on the core-condensation via the kinetic relaxation…
High-redshift quasar observations imply that supermassive black holes (SMBHs) larger than $\sim 10^9 ~ M_\odot$ formed before $z=6$. That such large SMBHs formed so early in the Universe remains an open theoretical problem. One possibility…
It has been proposed that the first, intermediate-mass ($\approx 10^{5-6}~M_\odot$) black holes might form through direct collapse of unpolluted gas in atomic-cooling halos exposed to a strong Lyman-Werner (LW) or near-infrared (NIR)…
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)…
The gravitational-wave detection by the LIGO-Virgo scientific collaboration shows that the black hole and neutron star (BH-NS) or BH-BH systems with a BH mass of tens of solar masses widely exist in the universe. Two main types of scenarios…
Among the most explored directions in the study of dense stellar systems is the investigation of the effects of the retention of supernova remnants, especially that of the massive stellar remnant black holes (BHs), in star clusters. By…