Related papers: Comments on Kormendy, Bender & Cornell (2011, Natu…
We argue that it is inconsistent to ignore the gravitational backreaction for on-shell superstring states at the Planck mass and beyond, and that these quantum states become Kerr black holes in the classical limit. Consequences are…
There is a growing literature on dyonic black holes as they appear in string theory. Here we examine the correspondence limit of a dyonic black hole which is not supersymmetric. Assuming the existence of a dyon with non-supersymmetric…
Sutter et al. have responded to the criticisms we made of their cosmic void catalogue in our recent paper presenting an alternative catalogue (Nadathur & Hotchkiss 2013). Unfortunately, their response contains several statements which are…
Recent work has confirmed that the masses of supermassive black holes, estimated from scaling relations with global properties such as the stellar masses of their host galaxies, may be biased high. Much of this may be caused by the…
Recent work on the dynamical evolution of galactic nuclei containing supermassive black holes is reviewed. Topics include galaxy structural properties; collisionless and collisional equilibria; loss-cone dynamics; and dynamics of binary and…
Using black-hole arguments with widely accepted premises, we show that it is extremely improbable that space is Euclidean, and that it is unspeakably improbable that space is hyperbolic. Independently, using an argument which makes no…
We study the relation between the properties of the bulge/disc components and the HI mass fraction of galaxies. We find that at fixed stellar mass, disc colours are correlated with the HI mass fraction, while bulge colours are not. The lack…
Black hole masses are tightly correlated with the stellar velocity dispersions of the bulges which surround them, and slightly less-well correlated with the bulge luminosity. It is common to use these correlations to estimate the expected…
To understand the physical origin of the close connection between supermassive black holes and their host galaxies, it is vital to investigate star formation properties in active galaxies. Using a large dataset of nearby type 1 active…
The celebrated treatment of continued gravitational collapse by Oppenheimer and Snyder is revisited and emended from some inherent flaws. The star contracts itself into a material point, not into a black hole.
Arguments for black hole formation in collisions of high-energy particles have rested on the emergence of a closed trapped surface in the classical geometry of two colliding Aichelburg-Sexl solutions. Recent analysis has, however, shown…
The investigation about the volume of a black hole is closely related to the quantum nature of the black hole. The entropy is a significant concept for this. A recent work by Majhi and Samanta [Phys. Lett. B 770 (2017) 314] after us…
The empirical model of Lu et al. 2014a for the relation between star formation rate and halo mass growth is adopted to predict the classical bulge mass ($M_{\rm cb}$) - total stellar mass ($M_\star$) relation for central galaxies. The…
We show that there is an inconsistency in the class of solutions obtained in Phys. Rev. D {\bf 95}, 084037 (2017). This inconsistency is due to the approximate relation between lagrangian density and its derivative for Non-Linear…
Bulges in spiral galaxies have been supposed to be classified into two types: classical bulges or pseudobulges. Classical bulges are thought to form by galactic merger with bursty star formation, whereas pseudobulges are suggested to form…
Comments to the review "Nonthermal Phenomena in Clusters of Galaxies" by Y.Rephaeli et al. (arXiv:0801.0982 [astro-ph]) that regard the presence of a hard X-ray excess in the Coma cluster, A2199, A2163 and the Bullet cluster.
The statistical relations between the masses of supermassive black holes (SMBHs) in disk galaxies and the kinematic properties of their host galaxies are analyzed. We use the radial velocity profiles for several galaxies obtained earlier at…
I consider recent observations of ultramassive black holes. These appear to confirm theoretical predictions that the relation between central black hole mass $M$ and spheroid velocity dispersion $\sigma$ has the same form $M \propto…
Astronomical observations have confirmed the existence of BHs and the occurrence of the Big Bang event to beyond any reasonable doubt. While quantum field theory and general theory of relativity predict the mass-spectrum of BHs to be…
While until recently they were often considered as exotic objects of dubious existence, in the last decades there have been overwhelming observational evidences for the presence of stellar mass black holes in binary systems, supermassive…