Related papers: The Host Galaxy and Central Engine of the Dwarf AG…

We investigate the host galaxy luminosities of BL Lac Objects (BLLs) and Radio Loud Quasars (RLQs) at z<0.5 imaged with the Hubble Space Telescope (HST). From a homogeneous treatment of the data we construct the host galaxy luminosity…

We report the discovery of extreme X-ray variability in a type 1 quasar: SDSS J$075101.42+291419.1$. It has a black hole mass of $1.6\times 10^7~\rm M_\odot$ measured from reverberation mapping (RM), and the black hole is accreting with a…

We present the emission properties of a sample of 3,579 type 1 AGN, selected based on the detection of broad H-alpha emission. The sample covers the range of black hole mass 10^6<M_BH/M_Sun<10^9.5 and luminosity in Eddington units 10^-3 <…

To examine the relationship between black hole mass and host galaxy velocity dispersion for low black hole masses, we have measured the velocity dispersions of 15 Seyfert 1 galaxies from the catalog of Greene & Ho (2004). These Seyferts…

We observed the Galactic black hole GX 339-4 with the Chandra High Energy Transmission Grating Spectrometer (HETGS) for 75 ksec during the decline of its 2002-2003 outburst. The sensitivity of this observation provides an unprecedented…

A mass correlation of central black holes and their spheroids ~0.002(within a factor of three) is suggested by Hubble Space Telescope (HST) and various ground-based CCD photometries of early type galaxies. The near-IR images of quasar hosts…

We present rest-frame $B$ and $I$ imaging of 35 low-redshift ($z < 0.5$) Palomar-Green quasars using the Hubble Space Telescope Wide Field Camera 3. We perform multi-component two-dimensional image decomposition to separate the host galaxy…

We investigate the relation between X-ray nuclear emission, optical emission line luminosities and black hole masses for a sample of 47 Seyfert galaxies. The sample, which has been selected from the Palomar optical spectroscopic survey of…

We have conducted a multiwavelength survey of 42 radio loud narrow-1ine Seyfert 1 galaxies (RLNLS1s), selected by searching among all the known sources of this type and omitting those with steep radio spectra. We analyse data from radio…

Black hole masses in active galactic nuclei (AGN) are difficult to measure using conventional dynamical methods, but can be determined using the technique of reverberation mapping. However, it is important to verify that the results of…

Here we present the spectropolarimetric observations of a sample of 30 Type 1 AGNs and an analysis of the observed polarization in these AGNs. The observations have been performed with the 6-meter telescope of SAO RAS using the modified…

As a newly discovered class of radio-loud active galactic nuclei (AGNs), the \gamma-ray detected narrow-line Seyfert 1 galaxies (NLS1s) launch powerful jets which are generally found only in blazars and radio galaxies. However, their black…

We have measured the stellar velocity dispersions (\sigma_*) and estimated the central black hole (BH) masses for over 900 broad-line active galactic nuclei (AGNs) observed with the Sloan Digital Sky Survey. The sample includes objects…

The recently discovered tight correlation between supermassive black hole mass and central velocity dispersion suggests a possibility to estimate the SMBH mass from the measured central velocity dispersion. However, for most AGNs it is…

UM 625, previously identified as a narrow-line active galactic nucleus (AGN), actually exhibits broad \ha\ and \hb\ lines whose width and luminosity indicate a low black hole mass of $1.6 \times 10^6$ \msun. We present a detailed…

We present the results of a 500 ksec long XMM-Newton observation and a 120 ksec long quasi-simultaneous Chandra observation of the Narrow Line Seyfert 1 galaxy 1H0707-495 performed in 2010 September. Consistent with earlier results by…

We analyze an X-ray flux-limited, complete sample of 93 AGN at z< 0.1, selected from the ROSAT Bright Survey. Two thirds of the sample are Seyfert 1 galaxies (Sy1) and one third are Narrow-Line Seyfert 1 galaxies (NLSy1). We have obtained…

Observationally established correlations between black hole mass and host galaxy structural/dynamical properties (like the M_BH - sigma relation) give support to the idea of an intimate link between the growth of black holes (BHs) and their…

Massive black holes (BHs) are detected in the centers of many nearby galaxies are linearly correlated with the luminosity of the host bulge (spheroid), the black hole mass being about 0.1% of the stellar mass. In active galaxies, the BH…

We investigate if the active galactic nucleus (AGN) of Mrk 590, whose supermassive black hole was until recently highly accreting, is turning off due to a lack of central gas to fuel it. We analyse new sub-arcsecond resolution ALMA maps of…