Double-peaked emission lines are believed to be originated from accretion disks around supermassive black holes (SMBHs), and about 3% of z < 0.33 AGNs are found to be double-peaked emitters. The quasar SDSS J153636.22+044127.0 has recently been identified with peculiar broad-line emission systems exhibiting multiple redshifts. We decompose the Hα and Hβ profiles into a circular Keplerian disk l...

A quantum mechanical description of black hole states proposed recently within non-perturbative quantum gravity is used to study the emission and absorption spectra of quantum black holes. We assume that the probability distribution of states of the quantum black hole is given by the “area” canonical ensemble, in which the horizon area is used instead of energy, and use Fermi’s golden rule to f...

The Galactic black hole candidate XTE J1752−223 was observed during the decay of its 2009 outburst with the Suzaku and XMM–Newton observatories. The observed spectra are consistent with the source being in the ‘intermediate’ and ‘low-hard’ states, respectively. The presence of a strong, relativistic iron emission line is clearly detected in both observations and the line profiles are found to b...

We explore the relation between the linear length of radio core and the central black hole mass for a sample of radio-loud active galactic nuclei (AGNs). An empirical relation between the size of the broad line region (BLR) and optical luminosity is used to estimate the size of the BLR. The black hole mass is derived from Hβ line width and the radius of the BLR on the assumption that the clouds...

The relativistic broad iron lines seen in the X-ray spectra of several active galaxies and Galactic black hole systems are reviewed. Most such objects require emission from within the innermost stable orbit of a non-rotating black hole, suggesting that the black holes are rapidly spinning Kerr holes. We discuss the soft excess, the broad iron line and the Compton hump characteristic of reflecti...

When oblique rows of black and white dots drifted horizontally across a mid-grey surround, the perceived direction of motion was shifted to be almost parallel to the dotted lines and was often nearly orthogonal to the real motion. The reason is that the black/white contrast signals between adjacent dots along the length of the line are stronger than black/grey or white/grey contrast signals acr...

Based on the measured sizes of broad line region of the reverberation-mapping AGN sample, two new empirical relations are introduced to estimate the central black hole masses of radio-loud high-redshift (z > 0.5) AGNs. First, using the archival IUE/HST spectroscopy data at UV band for the reverberation-mapping objects, we obtained two new empirical relations between the BLR size and Mgii /Civ e...

Schistura phamhringi, new stone loach, is described from Dutah Stream, tributary of the Yu River (Chindwin basin), near Larong Village, Chandel District, Manipur, India. It is distinguished from all its congeners by a unique combination of characters: 6-7 black saddles, each continued on both flanks forming broad diamond-shaped black bars with narrow ventral margin; bars superimposed on a grey ...

Because of the contamination of jets, using the size – continuum luminosity relation can overestimate the broad line region (BLR) size and black hole mass for radio-loud AGNs. We propose a new relation between the BLR size and Hβ emission line luminosity and present evidences for using it to get more accurate black hole masses of radio-loud AGNs. For extreme radio-loud AGNs such as blazars with...