Black hole atom as a dark matter particle candidate

We propose the new dark matter particle candidate - the "black hole atom", which is an atom with the charged black hole as an atomic nucleus and electrons in the bound internal quantum states. As a simplified model we consider the the central Reissner-Nordstrom black hole with the electric charge neutralized by the internal electrons in bound quantum states. For the external observers these objects would look like the electrically neutral Schwarzschild black holes. We suppose the prolific production of black hole atoms under specific conditions in the early universe.Comment: 5 pages, 1 figures, with additional reference

Ultra-hard fluid and scalar field in the Kerr-Newman metric

An analytic solution for the accretion of ultra-hard perfect fluid onto a moving Kerr-Newman black hole is found. This solution is a generalization of the previously known solution by Petrich, Shapiro and Teukolsky for a Kerr black hole. Our solution is not applicable for an extreme black hole due to violation of the test fluid approximation. We also present a stationary solution for a massless scalar field in the metric of a Kerr-Newman naked singularity.Comment: 9 pages, 3 figures, revtex4; v2: presentation improved, figures added, matches published versio

GRB Redshift Distribution is Consistent with GRB Origin in Evolved Galactic Nuclei

Recently we have elaborated a new cosmological model of gamma-ray burst (GRB) origin (1998, ApJ 502, 192), which employs the dynamical evolution of central dense stellar clusters in the galactic nuclei. Those clusters inevitably contain a large fraction of compact stellar remnants (CSRs), such as neutron stars (NSs) and stellar mass black holes (BHs), and close encounters between them result in radiative captures into short-living binaries, with subsequent merging of the components, thereby producing GRBs (typically at large distances from the nucleus). In the present paper, we calculate the redshift distribution of the rate of GRBs produced by close encounters of NSs in distant galactic nuclei. To this end, the following steps are undertaken: (i) we establish a connection between the parameters of the fast evolving central stellar clusters (i.e. those for which the time of dynamical evolution exceeds the age of the Universe) with masses of the forming central supermassive black holes (SMBHs) using a dynamical evolution model; (ii) we connect these masses with the inferred mass distributions of SMBHs in the galactic nuclei and the redshift distribution of quasars by assuming a certain `Eddington luminosity phase' in their activity; (iii) we incorporate available observational data on the redshift distribution of quasars as well as a recently found correlation between the masses of galaxies and their central SMBHs. The resulting redshift distribution of the GRB rate, which accounts for both fast and slowly evolving galactic nuclei is consistent with that inferred from the BATSE data if the fraction of fast evolving galactic nuclei is in the range $0.016-0.16$.Comment: LaTeX, 4 pages (incl. 1 figure), to appear in "After the Dark Ages: When Galaxies Were Young (the Universe at 2<z<5)", eds. S.S. Holt and E.P. Smit