Related papers: The Next-Generation Very Large Array: Supermassive…

The next-generation Event Horizon Telescope (ngEHT) will provide us with the best opportunity to investigate supermassive black holes (SMBHs) at the highest possible resolution and sensitivity. With respect to the existing Event Horizon…

Using the Next Generation Very Large Array (ngVLA), we will make a comprehensive inventory of intermediate-mass black holes (IMBHs) in hundreds of globular cluster systems out to a distance of 25 Mpc. IMBHs have masses of about 100 to…

In an EHT study of a Jy-level target, Safarzadeh et al. (2019) show how astrometric monitoring could constrain massive black hole binaries with the wide separations that make them long-lived against gravitational wave losses, and with the…

Pulsar timing arrays (PTAs) are on the verge of detecting low-frequency gravitational waves (GWs) from supermassive black hole binaries (SMBHBs). With continued observations of a large sample of millisecond pulsars, PTAs will reach this…

The Laser Interferometer Space Antenna (LISA) will be able to detect massive black hole mergers throughout the visible Universe. These observations will provide unique information about black hole formation and growth, and the role black…

We review the recent multifrequency studies of galactic black hole binaries, aiming at revealing the underlying emission processes and physical properties in these systems. The optical and infrared observations are important for determining…

Identifying methods to discover dual AGN has proven to be challenging. Several indirect tracers have been explored in the literature, including X/S-shaped radio morphologies and double-peaked (DP) emission lines in the optical spectra.…

In this work we focus on the search and detection of Massive black hole binary (MBHB) systems, including systems at high redshift. As well as expanding on previous works where we used a variant of Markov Chain Monte Carlo (MCMC), called…

A single space-based gravitational wave detector will push the boundaries of astronomy and fundamental physics. Having a network of two or more detectors would significantly improve source localization. Here we consider how dual networks of…

Thirteen dwarf galaxies have recently been found to host radio-selected accreting massive black hole (MBH) candidates, some of which are ``wandering" in the outskirts of their hosts. We present 9 GHz Very Long Baseline Array (VLBA)…

If binaries consisting of two 100 Msun black holes exist they would serve as extraordinarily powerful gravitational-wave sources, detectable to redshifts of z=2 with the advanced LIGO/Virgo ground-based detectors. Large uncertainties about…

Dual active galactic nuclei (DAGN) and supermassive black hole binaries (SMBHBs) at kpc and pc-scale separations, respectively, are expected during stages of galaxy merger and evolution. Their observational identification can address a…

The Andromeda galaxy (M\,31) hosts one of the nearest and most quiescent super-massive black holes, which provides a rare, but promising opportunity for studying the physics of black hole accretion at the lowest state. We have conducted a…

Here we summarize discussions and conclusions from the conference ``The Era of Binary Supermassive Black Holes: Coordination of Nanohertz-Frequency Gravitational-Wave Follow-up,'' held at the Aspen Center for Physics from February 2-7,…

Recent calculations indicate that radio emission from quasars at $z \sim$ 6 - 7 could be detected at much earlier stages of evolution, at $z \sim$ 14 - 15, by the Next-Generation Very Large Array (ngVLA) and the Square Kilometer Array…

This whitepaper describes how the VLASS could be designed in a manner to allow the identification of candidate dual active galactic nuclei (AGN) at separations <7 kpc. Dual AGN represent a clear marker of two supermassive black holes within…

We study how the angular resolution of LISA for merging massive black-hole binaries would be improved if we observe multiple gravitational wave ``images'' due to strong gravitational lensing. The correlation between fitting parameters is…

Since the initial detection of Gravitational Waves in 2015, 50 candidate events have been reported by the LIGO-Virgo-KAGRA collaboration. As the current generation of detectors move towards their design sensitivity the rate of these…

Supermassive black hole binaries (SMBHBs) are a natural outcome of galaxy mergers and should form frequently in galactic nuclei. Sub-parsec binaries can be identified from their bright electromagnetic emission, e.g., Active Galactic Nuclei…

Supermassive black holes (SMBHs) found in the centers of many galaxies have been recognized to play a fundamental active role in the cosmological structure formation process. In hierarchical formation scenarios, SMBHs are expected to form…