One of the most perplexing problems associated with the supermassive black hole at the center of our Galaxy is the origin of the young stars in its close vicinity. Using proper motion measurements and stellar number density counts based on 9 years of diffraction-limited K(2.2 μm)-band speckle imaging at the W. M. Keck 10meter telescopes, we have identified a new comoving group of stars, which w...

In this paper we report results of collisional N -body simulations of the dynamical evolution of equal-mass star clusters containing a massive central black hole. Each cluster is composed of between 5,000 to 180,000 stars together with a central black hole which contains between 0.2% to 10% of the total cluster mass. We find that for large enough black hole masses, the central density follows a...

The central black-hole masses of 85 radio-loud quasars are estimated using available data of Hβ line-width and optical continuum luminosity. The vast majority of the quasars in this sample have black-hole masses larger than 108M⊙, while a few quasars may contain relatively smaller black-holes. It is found that the radio-loudness decreases with the black-hole mass.

We present an analysis of the central cusp slopes and core parameters of early-type galaxies using a large database of surface brightness profiles obtained from Hubble Space Telescope observations. We examine the relation between the central cusp slopes, core parameters, and black hole masses in early-type galaxies, in light of two models that attempt to explain the formation of cores and densi...

We present a two-dimensional grid-based hydrodynamic simulation of a thin, viscous, locally isothermal corotating disk orbiting an equal-mass Newtonian binary point mass on a fixed circular orbit. We study the structure of the disk aftermultiple viscous times. The binarymaintains a central hole in the viscously relaxed diskwith radius equal to about twice the binary semimajor axis. Disk surface...

We present a simple scenario where the formation of galactic bulges was regulated by the dark halo gravity and regulated the growth of the central supermassive black hole. Assuming the angular momentum is low, we suggest that bulges form in a runaway collapse due to the ”gravothermal” instability once the central gas density or pressure exceeds certain threshold (Xu & Zhao 2007). We emphasize t...

UNLABELLED The study shows a promising next-generation surgical option for the correction of moderate to high ametropia. Hole implantable collamer lens (ICL), STAAR Surgical, is a posterior chamber phakic intraocular lens with a central artificial hole. As yet, however, no long-term comparison of the clinical results of the implantation of ICLs with and without such a hole has hitherto been con...

A tight correlation of black hole mass (MBH) and central velocity dispersion (σ) has been found recently for both active and quiescent galaxies. By applying this correlation, we develop a simple method to derive the inclination angles for a sample of 11 Seyfert 1 galaxies that have both measured central velocity dispersions and black hole masses estimated by reverberation mapping. These angles,...

We construct a model for the formation of black holes within galactic bulges. The initial state is a slowly rotating isothermal sphere, characterized by effective transport speed aeff and rotation rate Ω. The black hole mass is determined when the centrifugal radius of the collapse flow exceeds the capture radius of the central black hole. This model reproduces the observed correlation between ...

With Carlip’s boundary conditions, a standard Virasoro subalgebra with corresponding central charge for stationary dilaton black hole obtained in the low-energy effective field theory describing string is constructed at a Killing horizon. The statistical entropy of stationary dilaton black hole yielded by standard Cardy formula agree with its Bekenstein-Hawking entropy only if we take period T ...