In black hole (BH) X-ray binaries (XRBs), a misalignment between the spin axis of the BH and the orbital angular momentum can occur during the supernova explosion that forms the compact object. In this Letter, we present population synthesis (PS) models of Galactic BH XRBs and study the probability density function of the misalignment angle and its dependence on our model parameters. In our modeling, we also take into account the evolution of the misalignment angle due to accretion of material onto the BH during the XRB phase. The major factor that sets the misalignment angle for XRBs is the natal kick that the BH may receive at its formation. However, large kicks tend to disrupt binaries, while small kicks allow the formation of XRBs and naturally select systems with small misalignment angles. Our calculations predict that the majority (>67%) of Galactic field BH XRBs have rather small (<~10{deg}) misalignment angles, while some systems may reach misalignment angles as high as ~90{deg} and even higher. These results are robust among all PS models. The assumption of small misalignment angles is extensively used to observationally estimate BH spin magnitudes, and for the first time we are able to confirm this assumption using detailed PS calculations.
Photoelectric observations of the short period eclipsing binary BH Vir in B and V bands are presented. Comparing with earlier published observations, we found that there were smaller variations in the light curve (outside eclipse) in 1991 than in the previous data.
High-resolution spectroscopic observations around the H{alpha} line and BVRI photometry from 1993 to 2003 of the eclipsing short-period RS CVn star BH Vir are presented. ************************************************************************** * * * Sorry, but the author(s) never supplied the tabular material * * announced in the paper * * * **************************************************************************
This catalog contains a bibliography of statistical data analysis and pattern recognition algorithms that are multivariate. References to computer packages and books are given. The catalog is divided into nine sections, each with astronomical and general headings, and is offered in two versions, LaTeX and ASCII.
The data file contains a bibliography of 44,000 radial velocities for about 25,000 stars, from a compilation of about 2340 publications (see the "Note (3)" below). The authors estimate that 99% of stellar radial velocities published by June 1970 are contained in the surveyed volumes.
(adapted from the "Documentation for the Machine-Readable Version of the Detailed bibliography of the surface photometry of galaxies by Lee E. Brotzman and Robert S. Hill (ADC), SASC-T-1-5810-5006-84, July 1984) The bibliography supplies coded information about the methods of observation and reduction, types of photometric data, limiting surface brightness, and the general purpose of each paper for about 650 galaxies and 300 references.
The Bidelman-Parsons Spectroscopic and Bibliographical Catalog (BPSB; Parsons, Buta, and Bidelman 1980a, b) contains data compiled from the astronomical literature by W. P. Bidelman. These data include diverse catalogs and lists, especially from pre-1950 journals (minor as well as major), and from pre-1962 observatory publications. From more recent years, the data on any object frequently are limited to one item with a reference; for example, a spectral type. No data published after 1973 are included. Over 200 publications are represented. The BPSB has information on 40,312 objects. The catalog contains most of the same information on MK spectral types as the Catalogue of Stellar Spectra Classified in the Morgan-Keenan System (Jaschek, Conde, and de Sierra 1964) and its updates, but it also includes such items as spectral types without a luminosity class (certainly better than nothing); spectroscopic absolute magnitudes; notes on multiplicity; notes on high proper motion or radial velocity (with the values, if probably variable, or if greater than 60 km/s); unpublished remarks and spectral types from several sources, including Bidelman and Henize; and Bidelman's preliminary identifications of many sources in the Two-Micron Sky Survey (Neugebauer and Leighton 1969). Some of the longer lists included in the catalog are those of OB stars from the Tonantzintla-Tacubaya and Heidelberg-Koenigstuhl surveys (Iriarte and Chavira 1957; Chavira 1958; Klare and Szeidl 1966); that of OB stars with emission from the Case-Hamburg surveys (Hardorp et al. 1959; Stock, Nassau, and Stephenson 1960; Hardorp, Theile, and Voigt 1964; Nassau and Stephenson 1963; Hardorp, Theile, and Voigt 1965; Nassau, Stephenson, and MacConnell 1965; Stephenson and Sanduleak 1971); and stars from the General Catalogue of Variable Stars (Kukarkin et al. 1969); and the Catalogue of Suspected Variable Stars (Kukarkin et al. 1951, 1965). Although the catalog is mainly of stellar data, it includes many galactic nebulae of various kinds.
We have probed the pulsating variable star content of the isolated Local Group dwarf galaxy, DDO210 (Aquarius), using archival Advanced Camera for Surveys/Hubble Space Telescope imaging in the F475W and F814W passbands. We find a total of 32 RR Lyrae stars (24 ab-type; 8 c-type) and 75 Cepheid variables. The mean periods of the ab-type and c-type RR Lyrae stars are calculated to be <Pab>=0.609+/-0.011 and <Pc>=0.359+/-0.025d, respectively. The light-curve properties of the fundamental mode RR Lyrae stars yield a mean metallicity of <[Fe/H]>=-1.63+/-0.11dex for this ancient population, consistent with a recent synthetic colour-magnitude diagram analysis. We find this galaxy to be Oosterhoff-intermediate and lacking in high-amplitude, short-period ab-type RR Lyrae, consistent with behaviour recently observed for many dwarf spheroidals and ultrafaint dwarfs in the Local Group. We find a distance modulus of {mu}=25.07+/-0.12 as determined by the RR Lyrae stars, slightly larger but agreeing with recent distance estimates from the red giant branch tip. We also find a sizable population of Cepheid variables in this galaxy. We provide evidence in favour of most if not all of these stars being short-period classical Cepheids. Assuming all of these stars to be classical Cepheids, we find that most of these Cepheids are ~ 300 Myr old, with the youngest Cepheids being offset from the older Cepheids and the centre of the galaxy. We conclude that this may have resulted from a migration of star formation in DDO210.
We have obtained photometric time-series observations of stars in the open cluster NGC 2506, in order to study pulsating blue stragglers and eclipsing binaries. The data were obtained during a bi-site campaign in early 2005 which involved the Danish 1.54-m telescope at ESO, La Silla, and the Flemish Mercator telescope at La Palma, Spain. Based on these data we increased the number of known variables in NGC 2506 from 5 to 28 through the detection of 3 new pulsating blue stragglers, 15 gamma Doradus stars and 4 new eclipsing binaries, while one variable is of unknown type. We derived orbital periods for two previously known binaries, we performed a tentative mode-identification of the pulsating blue stragglers, and compared B- and I amplitude ratios and phase differences for the gamma Doradus stars to seismic models.
