Related papers: Black hole mass and binary model for BL Lac object…

[ABRIDGED] We study supermassive black hole binary mergers driven by angular momentum loss to small-scale gas discs. Such binaries form after major galaxy mergers, but their fate is unclear since hardening through stellar scattering becomes…

We report on unprecedented short-term variations detected in the optical flux from the black hole binary system, V4641 Sgr. Amplitudes of the optical fluctuations were larger at longer time scales, and surprisingly reached ~60% around a…

Blazar PG 1553+113 is thought to be a host of supermassive black hole binary (SMBHB) system. A 2.2-year quasi-periodicity in the $\gamma$-ray light curve was detected, possibly result of jet precession. Motivated by the previous studies…

The BL Lac PG 1553+113 has been continuously monitored in gamma rays with Fermi-LAT for over 9 years. Its updated light curve now includes 5 iterations of a main pattern comprising a high peak and a longer trough, with a period P \sim 2.2…

We measure black hole masses for 71 BL Lac objects from the Sloan Digital Sky Survey with redshifts out to z~0.4. We perform spectral decompositions of their nuclei from their host galaxies and measure their stellar velocity dispersions.…

OJ287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts which are predictable in a binary black hole model. The model predicted a major optical outburst in December 2015. We found that the…

How a black hole accretes matter and how this process is regulated are fundamental but unsolved questions in astrophysics. In transient black-hole binaries, a lot of mass stored in an accretion disk is suddenly drained to the central black…

We study the orbital evolution and accretion history of massive black hole (MBH) pairs in rotationally supported circumnuclear discs up to the point where MBHs form binary systems. Our simulations have high resolution in mass and space…

The models that seek to explain the reflection spectrum in black hole binaries usually invoke a point-like primary source of hard X-rays. This source illuminates the accretion disk and gives rise to the discrete (lines) and…

We consider a scenario for the longest duration gamma ray bursts, resulting from the collapse of a massive star in a close binary system with a companion black hole. The primary black hole born during the core collapse is spun up and…

Stellar-mass black holes have all been discovered through X-ray emission, which arises from the accretion of gas from their binary companions (this gas is either stripped from low-mass stars or supplied as winds from massive ones). Binary…

By a method of population synthesis we construct a model of dark matter (DM) accretion onto binary black holes (BHs), and investigate the merger rate of the binary BHs. We find that the merger rate can weakly increase (less than 10\%).…

We consider the accretion of dark energy by constituent black holes in binary formations during the present epoch of the Universe. In the context of an observationally consistent dark energy model, we evaluate the growth of black holes'…

In a binary system, the gravitational potential of the primary black hole may play an important role in enhancing the fallback accretion onto the lighter compact object newly formed in the second supernova explosion. As a result, the final…

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…

We review the formation scenarios for binary black holes, and show that their coalescence rate depends very strongly on the outcome of the second mass transfer. However, the observations of IC10 X-1, an binary with a massive black hole…

Both theoretical models and observational evidence indicate that jets and/or outflows driven by central active supermassive black holes exert a significant feedback effect on the overall properties of their host galaxies. Theoretical models…

We analyze the mass distribution of stellar black holes derived from the light and radial velocity curves of optical stars in close binary systems using dynamical methods. The systematic errors inherent in this approach are discussed. These…

Accretion of material onto a black hole drags any magnetic fields present inwards, increasing their strength. Theory predicts that sufficiently strong magnetic fields can halt the accretion flow, producing a magnetically arrested disk…

Because they are likely to accrete substantial amounts of interstellar gas, merging supermassive binary black holes are expected to be strong multimessenger sources, radiating gravitational waves, photons from thermal gas, and photons from…