Related papers: AMUSE-Virgo II. Down-sizing in black hole accretio…
The globular cluster M15 has recently been found to host a possible central black hole with a mass of ~2000 solar masses. A deep, high-resolution Chandra image failed to detect the "nucleus" of the cluster in X-rays. The upper limit on the…
Intermediate-mass black holes (IMBHs) with masses below ($2 \times 10^5 M_{\odot}$) are pivotal in understanding the origin and growth mechanisms of supermassive black holes (SMBHs) in galactic nuclei. This study focuses on the search and…
Ultra-luminous X-ray sources are extragalactic objects located outside the nucleus of the host galaxy with bolometric luminosities >10^39 erg s^-1. These extreme luminosities - if the emission is isotropic and below the theoretical (i.e.…
Environmental effects are believed to play an important yet poorly understood role in triggering accretion events onto the supermassive black holes (SMBHs) of galaxies (Active Galactic Nuclei; AGN). Massive clusters, which represent the…
Intermediate-mass black holes (IMBHs; $M_{BH} <2*10^{5} M_{\odot}$) in galaxy centers are cruciel for painting a coherent picture of the formation and growth of supermassive black holes (SMBHs). Using Big Data analysis, we identified 305…
Recent studies of active galactic nuclei (AGN) found a statistical inverse linear scaling between the X-ray normalized excess variance $\sigma_{\rm rms}^2$ (variability amplitude) and the black hole mass spanning over $M_{\rm BH}=10^6-…
We present Chandra observations of 12 galaxies that contain supermassive black holes with dynamical mass measurements. Each galaxy was observed for 30 ksec and resulted in a total of 68 point source detections in the target galaxies…
We present the results of a 8.4 GHz Very Large Array radio survey of early-type galaxies extracted from the ACS Virgo Cluster Survey. The aim of this survey is to investigate the origin of radio emission in early-type galaxies and its link…
We study the ratio $R$ between the luminosity of the torus and that of the accretion disk, inferred from the relativistic model KERRBB for a sample of approximately 2000 luminosity-selected radio-quiet Type I active galactic nuclei from the…
Intermediate mass black holes (10^2 < M_BH< 10^5 Msun) are an open question in our understanding of black hole evolution and growth. They have long been linked to dense star cluster environments thanks to cluster dynamics, but there are a…
We present deep near-infrared spectroscopy of six quasars at 6.1<z<6.7 with VLT/X-Shooter and Gemini-N/GNIRS. Our objects, originally discovered through a wide-field optical survey with the Hyper Suprime-Cam (HSC) Subaru Strategic Program…
We investigate the relationship between black hole mass and host galaxy properties for active galaxies with the lowest black hole masses currently known in galaxy nuclei. Hubble Space Telescope imaging confirms that the host galaxies have…
A new sample of 204 low-mass black holes (LMBHs) in active galactic nuclei (AGNs) is presented with black hole masses in the range of (1-20) * 10^5 M_sun. The AGNs are selected from a systematic search among galaxies in the Seventh Data…
We report stellar velocity dispersion measurements for a sample of 28 AGN host galaxies including our previous work. Using the mass-dispersion ($M_{\bullet}-\sigma$) and the fundamental plane relations, we estimate the black hole mass for a…
Estimation of the black hole mass in bright X-ray sources of nearby galaxies is crucial to the understanding of these systems and their formation. However, the present allowed black hole mass range spans five order of magnitude (10Msun < M…
Most ultraluminous X-ray sources (ULXs) display a typical set of properties not seen in Galactic stellar-mass black holes (BHs): higher luminosity Lx > 3 10^39 erg/s, unusually soft X-ray components (kT < 0.3 keV) and a characteristic…
Using ground-based gravitational-wave detectors, we probe the mass function of intermediate-mass black holes (IMBHs) wherein we also include BHs in the upper mass gap $\sim 60-130~M_\odot$. Employing the projected sensitivity of the…
We investigate the relation between the X-ray nuclear emission, optical emission line, radio luminosity and black hole mass for a sample of nearby Seyfert galaxies. Strong linear correlations between the 2-10 keV and [OIII], radio…
We have performed a detailed analysis of the local super-massive black-hole (SMBH) mass function based on both kinematic and photometric data and derived an accurate analytical fit in the range 10^6 <= (M_BH/M_sun) <= 5*10^9. We find a…
This is the second in a series of papers reporting on a large reverberation mapping (RM) campaign to measure black hole (BH) mass in high accretion rate active galactic nuclei (AGNs). The goal is to identify super-Eddington accreting…