Synthetic catalog of black holes in the Milky Way

We present an open-access database which includes a synthetic catalog of black holes in the Milky Way. To calculate evolution of single and binary stars we used updated population synthesis code StarTrack. We applied a new model of star formation history and chemical evolution of Galactic disk, bulge and halo synthesized from observational and theoretical data. We find that at the current moment Milky Way (disk+bulge+halo) contains about 1.2 x 10^8 single black holes with average mass of about 14 Msun and 9.3 x 10^6 BHs in binary systems with average mass of 19 Msun. We present basic statistical properties of BH populations such as distributions of single and binary BH masses, velocities, orbital parameters or numbers of BH binary systems in different evolutionary configurations. We find that the most massive BHs are formed in mergers of binary systems, such as BH-MS, BH+He, BH-BH. The metallicity of stellar population has a significant impact on the final BH mass due to the stellar winds. Therefore the most massive single BH in our simulation, 113 Msun, originates from a merger of a helium star and a black hole in a low metallicity stellar environment in Galactic halo. The most massive BH in binary system is 60 Msun and was also formed in Galactic halo. We constrain that only 0.006% of total Galactic halo mass (including dark matter) could be hidden in the form of stellar origin BHs which are not detectable by current observational surveys. Galactic binary BHs are minority (10% of all Galactic BHs) and most of them are in BH-BH systems. The current Galactic merger rates for two considered common envelope models which are: 3-81 Myr^-1 for BH-BH, 1-9 Myr^-1, for BH-NS and 14-59 Myr^-1 for NS-NS systems. Data files are available at https://bhc.syntheticuniverse.org/.Comment: 21 pages, A&A accepted, data from catalog available onlin

Distribution of compact object mergers around galaxies

Compact object mergers are one of the currently favored models for the origin of GRBs. The discovery of optical afterglows and identification of the nearest, presumably host, galaxies allows the analysis of the distribution of burst sites with respect to these galaxies. Using a model of stellar binary evolution we synthesize a population of compact binary systems which merge within the Hubble time. We include the kicks in the supernovae explosions and calculate orbits of these binaries in galactic gravitational potentials. We present the resulting distribution of merger sites and discuss the results in the framework of the observed GRB afterglows.Comment: 8 pages, 5 figures, submitted to MNRA

Initial Populations of Black Holes in Star Clusters

Using an updated population synthesis code we study the formation and evolution of black holes (BHs) in young star clusters following a massive starburst. This study continues and improves on the initial work described by Belczynski, Sadowski & Rasio (2004). In our new calculations we account for the possible ejections of BHs and their progenitors from clusters because of natal kicks imparted by supernovae and recoil following binary disruptions. The results indicate that the properties of both retained BHs in clusters and ejected BHs (forming a field population) depend sensitively on the depth of the cluster potential. In particular, most BHs ejected from binaries are also ejected from clusters with central escape speeds Vesc < 100 km/s. Conversely, most BHs remaining in binaries are retained by clusters with Vesc > 50 km/s. BHs from single star evolution are also affected significantly: about half of the BHs originating from primordial single stars are ejected from clusters with Vesc < 50 km/s. Our results lay a foundation for theoretical studies of the formation of BH X-ray binaries in and around star clusters, including possible ultra-luminous sources, as well as merging BH--BH binaries detectable with future gravitational-wave observatories.Comment: 35 pages, 8 tables, 17 figures; resubmitted to ApJ (revised version

GRB030406 an extremely hard burst outside of the INTEGRAL field of view

Using the IBIS Compton mode, the INTEGRAL satellite is able to detect and localize bright and hard GRBs, which happen outside of the nominal INTEGRAL telescopes field of view. We have developed a method of analyzing such INTEGRAL data to obtain the burst location and spectra. We present the results for the case of GRB030406. The burst is localized with the Compton events, and the location is consistent with the previous Interplanetary Network position. A spectral analysis is possible with the detailed modeling of the detector response for such a far off-axis source with the offset of 36.9 $^\circ$. The average spectrum of the burst is extremely hard: the photon index above 400 \kev is -1.7, with no evidence of a break up to 1.1 \mev at 90% confidence level.Comment: Astronomy and Astrophysics in pres

Integrated circuits and molecular components for stress and feeding: implications for eating disorders: Integrated circuits and molecular components

Eating disorders are complex brain disorders that afflict millions of individuals worldwide. The etiology of these diseases is not fully understood, but a growing body of literature suggests that stress and anxiety may play a critical role in their development. As our understanding of the genetic and environmental factors that contribute to disease in clinical populations like anorexia nervosa, bulimia nervosa and binge eating disorder continue to grow, neuroscientists are using animal models to understand the neurobiology of stress and feeding. We hypothesize that eating disorder clinical phenotypes may result from stress-induced maladaptive alterations in neural circuits that regulate feeding, and that these circuits can be neurochemically isolated using animal model of eating disorders