Related papers: Spins of primordial binary black holes before coal…
We argue that supermassive black hole growth in AGN occurs via sequences of randomly--oriented accretion discs with angular momentum limited by self--gravity. These stably co-- or counter--align with the black hole spin with almost equal…
We explore the possible spectrum of binary mergers of sub-solar mass black holes formed out of dark matter particles interacting via a dark electromagnetism. We estimate the properties of these dark black holes by assuming that their…
The age of gravitational wave (GW) astronomy has begun, and black hole (BH) mergers detected by LIGO are providing novel constraints on massive star evolution. A major uncertainty in stellar theory is the angular momentum (AM) transport…
In this paper, we consider the hypothesis that fractions of dark matter could be constituted by primordial black holes (PBHs). To test this possibility, we work out the observational properties of a static black hole embedded in the dark…
The coalescence of massive black holes generates gravitational waves (GWs) that will be measurable by space-based detectors such as LISA to large redshifts. The spins of a binary's black holes have an important impact on its waveform.…
We investigate a new mechanism to create large curvature perturbations on small scales due to parameter resonance in a single-field inflationary model with a small periodic structure upon the potential. After reentering the horizon, the…
Primordial black holes (PBHs) are supposed to form from the collapse of over-densed regions generated by large scalar curvature perturbations in the radiation dominated era. Despite decades of various independent observations, the nature of…
Binary black hole systems in the pre-coalescence stage are numerically constructed by demanding that the associated spacetime admits a helical Killing vector. Comparison with third order post-Newtonian calculations indicates a rather good…
The abundance of primordial black holes (PBHs) in the mass range $0.1 - 10^3 M_\odot$ can potentially be tested by gravitational wave observations due to the large merger rate of PBH binaries formed in the early universe. To put the…
Primordial black holes (PBHs) are those which may have formed in the early Universe and affected the subsequent evolution of the Universe through their Hawking radiation and gravitational field. To constrain the early Universe from the…
We review numerous arguments for primordial black holes (PBHs) based on observational evidence from a variety of lensing, dynamical, accretion and gravitational-wave effects. This represents a shift from the usual emphasis on PBH…
While the Advanced LIGO and Virgo gravitational-wave experiments now regularly observe binary black hole mergers, the evolutionary origin of these events remains a mystery. Analysis of the binary black hole spin distribution may shed light…
Massive binary black holes form at the centre of galaxies that experience a merger episode. They are expected to coalesce into a larger black hole, following the emission of gravitational waves. Coalescing massive binary black holes are…
Close stellar binaries are prone to undergo a phase of stable mass transfer in which a star loses mass to its companion. Assuming that the donor star loses mass along the instantaneous interstellar axis, we derive the orbit-averaged…
GW231123, the heaviest binary black hole merger detected by the LIGO-Virgo-KAGRA Collaboration to date, lies in the pair-instability mass gap and exhibits unusually high component spins. In this Letter, we show that both merging black holes…
The relation between the mass and spin of stellar-mass binary black holes (BBHs) has been proposed to be a smoking gun for the presence of multiple formation channels for compact objects. First-generation black holes (BHs) formed by…
We study the evolution of a massive black hole pair in a rotationally supported nuclear disc. The distributions of stars and gas mimic the nuclear region of a gas-rich galaxy merger remnant. Using high-resolution SPH simulations, we follow…
The maximum mass of black holes formed in isolated binaries is determined by stellar winds and the interactions between the binary components. We consider for the first time fully self-consistent detailed stellar structure and binary…
Recent studies indicate that the progenitors of merging black hole (BH) binaries from young star clusters can undergo a common envelope phase just like isolated binaries. If the stars emerge from the common envelope as naked cores, tidal…
We review our semi-analytic model of stellar black hole (BH) mass growth by gas accretion in gas-rich stellar clusters during their birthstage within the first $\sim 10\,{\rm Myr}$ after the first stellar formation event. Such proto-stellar…