Related papers: Testing the binary black hole paradigm through the…
Quasars show a remarkable degree of atomic emission line-broadening, an observational feature which, in conjunction with a radial distance estimate for this emission from the nucleus is often used to infer the mass of the central…
We model the electromagnetic emission signatures of massive black hole binaries (MBHBs) with an associated gas component. The method comprises numerical simulations of relativistic binaries and gas coupled with calculations of the physical…
Gas within the influence sphere of accreting massive black holes is responsible for the emission of the broad lines observed in optical-UV spectra of unobscured active galactic nuclei. Since the region contributing the most to the broad…
Periodic quasars have been suggested to host supermassive binary black holes (BBHs) in their centers, and their optical/UV periodicities are interpreted as caused by either the Doppler-boosting (DB) effect of continuum emission from the…
A significant number of stellar-mass black-hole (BH) binaries may merge in galactic nuclei or in the surrounding gas disks. With purposed space-borne gravitational-wave observatories, we may use such a binary as a signal carrier to probe…
In a previous work, we have identified the spin of the dominant black hole of a binary from its jet properties. Analysing Very Long Baseline Array (VLBA) observations of the quasar S5~1928+738, taken at $15$-GHz during $43$ epochs between…
Radial velocity monitoring has revealed the presence of moving broad emission lines in some quasars, potentially indicating the presence of a sub-parsec binary system. Phase-referenced, near-infrared interferometric observations could map…
We present an improved semi-analytic model for calculation of the broad optical emission-line signatures from sub-parsec supermassive black hole binaries (SBHBs) in circumbinary disks. The second-generation model improves upon the treatment…
A theory is derived relating the configuration of the cores of active galaxies, specifically candidates for presumed super-massive black hole binaries (SMBHBs), to time-dependent changes in images of those galaxies. Three deflection…
The broad emission lines (BELs) emitted by Active Galactic Nuclei respond to variations in the ionizing continuum emission from the accretion disk surrounding the central supermassive black hole (SMBH). This reverberation response provides…
We investigate on the spectral properties of an active black hole, member of a massive (10^7 - 10^9 Msun) sub-parsec black hole binary. We work under the hypothesis that the binary, surrounded by a circum-binary disc, has cleared a gap, and…
Context. An optically thick, geometrically thin accretion disk (AD) around a supermassive black hole might contribute to broad-line emission in type-1 active galactic nuclei (AGN). However, emission line profiles are most often not…
Central black hole masses for 118 spiral galaxies representing morphological stages S0/a through Sc and taken from the large spectroscopic survey of Ho, Filippenko & Sargent (1997) are derived using 2MASS Ks data. Black hole (BH) masses are…
We study the contributions to the relativistic Fe $K_{\alpha}$ line profile from higher order images (HOIs) produced by strongly deflected rays from the disk which cross the plunging region, located between the innermost stable circular…
Gravitational wave detections offer insights into the astrophysical populations of black holes in the universe and their formation processes. Detections of binaries consisting of black holes lying outside the bulk distribution of the…
We have modeled the time-variable profiles of the Halpha emission line from the non-axisymmetric disk and debris tail created in the tidal disruption of a solar-type star by a million solar mass black hole. Two tidal disruption event…
The precession of astrophysical jets produced by active-galactic nuclei is likely related to the dynamics of the accretion disks surrounding the central supermassive black holes (BHs) from which jets are launched. The two main mechanisms…
We have modeled the time-variable profiles of the Halpha emission line from the non-axisymmetric disk and debris tail created in the tidal disruption of a solar-type star by a million solar mass black hole. We find that the line profiles at…
The bright blazar OJ 287 is the best-known candidate for hosting a supermassive black hole binary system. It inspirals due to the emission of nanohertz gravitational waves (GWs). Observations of historical and predicted quasi-periodic…
In the manuscript, a candidate of sub-pc binary black hole (BBH) system is reported in SDSS J1257+2023 through different properties of broad Balmer emission lines. After subtractions of host galaxy contributions, Gaussian functions are…