Related papers: Prospects for observing supermassive black hole bi…

We investigate the presence of supermassive black hole (SMBH) binary signatures and the feasibility of identifying them through X-ray reflection spectra. The X-ray emitting region is modeled as a set of two mini-disks bound to the…

Theoretically, bound binaries of massive black holes are expected as the natural outcome of mergers of massive galaxies. From the observational side, however, massive black hole binaries remain elusive. Velocity shifts between narrow and…

The Laser Interferometer Space Antenna (LISA) will be capable of detecting gravitational waves (GWs) in the milli-Hertz band. Among various sources, LISA will detect the coalescence of supermassive black hole binaries (SMBHBs). Accurate and…

Rotating black holes can generate boson clouds via superradiance when the boson's Compton wavelength is comparable to the black hole's size. In binary systems, these clouds can produce distinctive observational imprints. Recent studies…

Pulsar timing arrays (PTAs) are Galactic-scale gravitational wave (GW) detectors consisting of precisely-timed pulsars distributed across the sky. Within the decade, PTAs are expected to detect the nanohertz GWs emitted by close-separation…

Hypervelocity binaries (HVBs) can be produced by a close encounter between stellar binaries and supermassive black hole (SMBH)-intermediate massive black hole (IMBH) binaries. We perform scattering experiments between tight stellar binaries…

The radio galaxy 0402+379 is believed to host a supermassive black hole binary (SMBHB). The two compact core sources are separated by a projected distance of 7.3 pc, making it the most (spatially) compact resolved SMBHB known. We present…

We find that the majority of systems hosting multiple tidal disruptions are likely to contain hard binary SMBH systems, and also show that the rates of these repeated events are high enough to be detected by LSST over its lifetime.…

We present the results of a systematic search for massive black hole binaries in the Sloan Digital Sky Survey spectroscopic database. We focus on bound binaries, under the assumption that one of the black holes is active. In this framework,…

We analyze triple systems composed of the super massive black hole (SMBH) near the center of M87 and a pair of black holes (BHs) with masses in the range $10-10^3$ $M_{\odot}$. We consider the post Newtonian precession as well as the…

We estimate the expected signal-to-noise ratios (SNRs) from the three phases (inspiral,merger,ringdown) of coalescing binary black holes (BBHs) for initial and advanced ground-based interferometers (LIGO/VIRGO) and for space-based…

We present analysis of Chandra X-ray observations of seven quasars that were identified as candidate sub-parsec binary supermassive black hole (SMBH) systems in the Catalina Real-Time Transient Survey (CRTS) based on apparent periodicity in…

Accreting supermassive binary black holes (SMBBHs) are potential targets for multi-messenger astronomy as they emit gravitational waves (GW) while their environment emits electromagnetic (EM) waves. In order to get the most out of a joint…

Gravitational radiation arising from the inspiral and merger of binary black holes (BBH's) is a promising candidate for detection by kilometer-scale interferometric gravitational wave observatories. This paper discusses a serious obstacle…

Variable active galactic nuclei showing periodic light curves have been proposed as massive black hole binary (MBHB) candidates. In such scenarios the periodicity can be due to relativistic Doppler-boosting of the emitted light. This…

We outline the eccentricity evolution of sub-parsec massive black hole binaries (MBHBs) forming in galaxy mergers. In both stellar and gaseous environments, MBHBs are expected to grow large orbital eccentricities before they enter the…

Observational evidence has been mounting for the existence of intermediate mass black holes (IMBHs, 10^2-10^5 Msun), but observing them at all, much less constraining their masses, is very challenging. In one theorized formation channel,…

Coalescing massive black hole binaries (MBHBs) are one of primary sources for space-based gravitational wave (GW) observations. The mergers of these binaries are expected to give rise to detectable electromagnetic (EM) emissions with a…

Intermediate mass black holes (IMBHs) have masses between the $10^2\!-\!10^6$ M$_\odot$ and are key to our understanding of the formation of massive black holes. The known population of IMBH remains small, with a few hundred candidates and…

We present an overview of recent numerical advances in the theoretical characterization of massive binary black hole (MBBH) mergers in astrophysical environments. These systems are among the loudest sources of gravitational waves (GWs) in…