Related papers: Testing the binary black hole paradigm through the…
Hierarchical triple evolution provides a promising alternative to isolated binary formation models for black holes (BHs) and neutron stars (NSs) with low-mass stellar companions. To search for tertiaries, we perform deep, adaptive…
There is now abundant evidence that the luminosity of the Galactic super-massive black hole (SMBH) has not always been as low as it is nowadays. The observation of varying non-thermal diffuse X-ray emission in molecular complexes in the…
Supermassive black hole binaries may be detectable by an upcoming suite of gravitational wave experiments. Their binary nature can also be revealed by radio jets via a short-period precession driven by the orbital motion as well as the…
An analytic model of the evolution of a rotating black hole (BH) is proposed by considering the coexistence of disk accretion with the Blandford-Znajek process. The evolutionary characteristics of the BH are described in terms of three…
Optical variability of 3C 120 is discussed in the framework of jet precession. Specifically, we assume that the observed long-term periodic variability is produced by the emission from an underlying jet with a time-dependent boosting factor…
The photometric light curve of PG1302-102 shows periodic variability which makes this object one of the most plausible supermassive black hole binary candidate. Interestingly, the most recent study of its updated optical light curve reports…
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…
The Galactic Black hole candidate XTE J1752-223 was observed during the decay of its 2009 outburst with the Suzaku and XMM-Newton observatories. The observed spectra are consistent with the source being in the ''intermediate`` and…
We present a new observational test to identify massive black hole binaries in large multi-epoch spectroscopical catalogues and to probe the real nature of already proposed binary candidates. The test is tailored for binaries with…
Optical periodicity QSOs found by transient surveys are suggested to be sub-parsec supermassive binary black holes (BBHs). An intriguing interpretation for the periodicity of some of those QSOs is that the continuum is radiated from the…
Nearly 210 binary black hole (BBH) mergers have been observed by the LIGO-Virgo-KAGRA network during its four observing runs. Generic BBHs are spinning, and their spins are misaligned with the orbital angular momentum $\vec{L}$. These…
In the context of the evolution of large structures in the Universe, it is unclear whether active galaxies are a phase which each galaxy undergoes, and what is the importance of the evolution of black holes in their centers. Binary black…
Stellar-mass binary black holes may have circumbinary disks if formed through common-envelope evolution or within gaseous environments. Disks can drive binaries into wider and more eccentric orbits, while gravitational waves harden and…
We present inferences on the geometry and kinematics of the broad-Hbeta line-emitting region in four active galactic nuclei monitored as a part of the fall 2010 reverberation mapping campaign at MDM Observatory led by the Ohio State…
Relativistic emission lines generated by thin accretion disks around rotating black holes are an important diagnostic tool for testing gravity near the horizon. The iron K-line is of special importance for the interpretation of the X-ray…
PG1302-102 is thought to be a supermassive binary black hole (BBH) system according to the periodical variations of its optical and UV photometry, which may be interpreted as being due to the relativistic Doppler boosting of the emission…
Double peaked broad emission lines in active galactic nuclei are generally considered to be formed in an accretion disc. In this paper, we compute the profiles of reprocessing emission lines from a relativistic, warped accretion disc around…
The general-relativistic phenomenon of spin-induced orbital precession has not yet been observed in strong-field gravity. Gravitational-wave observations of binary black holes (BBHs) are prime candidates, since we expect the astrophysical…
We discuss prospects of identifying and characterizing black hole (BH) companions to normal stars on tight but detached orbits, using photometric data from the Transiting Exoplanet Survey Satellite (TESS). We focus on the following two…
Some BL Lacertae objects show a periodic behaviour in their light curves that is often attributed to the orbital motion of a central binary black hole system. On this basis, and assuming a circular orbit, Rieger and Mannheim have recently…