The nature of the gamma-ray burst (GRB) central engine still remains an enigma. Entities widely believed to be capable powering extreme jets are magnetars and black holes. maximum rotational energy that is available in a millisecond magnetar form jet ?1052 erg. We identify eight long GRBs whose jet-opening angle-corrected energetics prompt emission episode >1052 erg with high confidence level a...

Several recent approaches to black hole entropy obtain the density of states from the central charge of a Liouville theory. If Liouville theory is coupled to a dynamical spacetime background, however, the classical central charge vanishes. I show that the central charge can be restored by introducing appropriate constraints, which may be interpreted as fall-off conditions at a boundary such as ...

The Galactic Center shows evidence for the presence of three important AGN ingredients: a Black Hole (M• ∼ 10 M⊙), an accretion disk (10 −8.5 − 10M⊙/yr) and a powerful jet (jet power ≥ 10% disk luminosity). However, the degree of activity is very low and can barely account for the energetics of the whole central region. Neverthelss, in the very inner arsecond the central engine becomes dominant...

The dust clouds in the torus of the quasar are irradiated by the central source, and the clouds at the inner radius of the torus re-radiate mostly in the near-infrared (NIR) wavebands. The ratio of the near-infrared luminosity to the bolometric luminosity LNIR/Lbol can therefore reflect the torus geometry to some extent. We find a significant correlation between the ratio of the near-infrared l...

We simulate the accretion of high-density dwarf galaxies by low-density giant galaxies, using models that contain both power-law central density cusps and central point masses representing supermassive black holes. The final density profiles of the merger remnants are always similar to the initial density profile of the giant galaxy, for two reasons. 1. The density of the dwarf galaxy is reduce...

In this study, the analysis of transverse vibrations of rectangular plate with circular central hole with different boundary conditions is studied and the natural frequencies and natural modes of a rectangular plate with circular hole have been obtained. To solve the problem, it is necessary to use both Cartesian and polar coordinate system. The complexity of the method is to apply an appropria...

PURPOSE To analyze the preoperative results of multifocal electroretinography (mfERG) in the fellow eyes of patients with idiopathic unilateral macular hole and to evaluate the usefulness of this method in predicting the likelihood of macular hole formation in the fellow eye. METHODS Over a period of 5 years, 80 eyes of 40 patients (mean age, 64.9 years) with unilateral idiopathic macular hol...

The importance of the radiative output from massive black holes at the centers of elliptical galaxies is not in doubt, given the well established relations among electromagnetic output, black hole mass and galaxy optical luminosity. We show how this AGN radiative output affects the hot ISM of an isolated elliptical galaxy with the aid of a high-resolution hydrodynamical code, where the cooling ...