相关论文: Binary Galaxies in the Local Supercluster and Its …

We describe spectroscopic observations of 21 low-mass (<0.45 M_sun) white dwarfs (WDs) from the Palomar-Green Survey obtained over four years. We use both radial velocities and infrared photometry to identify binary systems, and find that…

We study a sample of 43 early-type galaxies, selected from the SDSS because they appeared to have velocity dispersion > 350 km/s. High-resolution photometry in the SDSS i passband using HRC-ACS on board the HST shows that just less than…

We study the statistical properties of the wide binary population in the Galaxy field with projected separations larger than 200 AU by constructing the stellar angular two-point correlation function (2PCF) from a homogeneous sample of…

We use a sample of 220 face-on bulge-less galaxies situated in the low density environment to estimate their total mass via orbital motions of supposed rare satellites. Our inspection reveals 43 dwarf companions having the mean projected…

The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with…

We report on the results of a survey for radial velocity variability in a heterogeneous sample of very low-mass stars and brown dwarfs. One distinguishing characteristic of the survey is its timespan, which allows an overlap between…

We use analytical and N-body methods to examine the survival of wide stellar binaries against repeated encounters with dark substructures orbiting in the dark matter haloes of dwarf spheroidal galaxies (dSphs). Our models adopt…

We present HST/ACS images and color-magnitude diagrams for 25 nearby galaxies with radial velocities V_LG < 500 km/s. Distances are determined based on the luminosities of stars at the tip of the red giant branch that range from 2 Mpc to 12…

Using SDSS Data Release 6, we construct two independent samples of candidate stellar wide binaries selected as i) pairs of unresolved sources with angular separation in the range 3'' - 16'', ii) common proper motion pairs with 5'' - 30''…

We present the first discoveries of the double-lined double white dwarf (DBL) survey that targets over-luminous sources with respect to the canonical white dwarf cooling sequence according to a set of well-defined criteria. The primary goal…

A magnitude limited sample of nearly 9000 early-type galaxies, in the redshift range 0.01 < z < 0.3, was selected from the Sloan Digital Sky Survey using morphological and spectral criteria. The sample was used to study how early-type…

We consider seven distant galaxies with clearly evident spiral structure from HST images. Three of these were chosen from Vogt et al. (1996) (VFP) and have measured rotational velocities. Five were chosen from the Medium Deep Survey and are…

We present r'- or i'-band WIYN images of the fields of 15 Sloan Digital Sky Survey quasars that have spectra exhibiting intervening MgII absorption-line systems with rest equivalent widths 2.7A \le REW \le 6.0A and redshifts 0.42 < z_{abs}…

A sample of close major-merger pairs (projected separation ${\rm 5 \leq r \leq 20 h^{-1}}$ kpc, ${\rm K_s}$ band magnitude difference $\delta {\rm K_s} \leq 1$ mag) is selected from the matched 2MASS-2dFGRS catalog of Cole et al. (2001).…

We present updated results of a high-resolution, magnitude limited (Ks<12 mag) imaging survey of nearby low-mass M6.0-M7.5 field stars. The observations were carried out using adaptive optics at the Gemini North, VLT, Keck II, and Subaru…

In the region of the sky limited by the coordinates RA$=7.0^h...12.0^h$, Dec$=0^\circ...+20^\circ$ and extending from the Virgo Cluster to the South Pole of the Local Supercluster, we consider the data on the galaxies with radial velocities…

Characterizing the local space density of double degenerate binary systems is a complementary approach to broad sky surveys of double degenerates to determine the expected rates of white dwarf binary mergers, in particular those that may…

Ultra-faint dwarf galaxies (UFDs) show extreme dynamical mass-to-light ratios of approximately 100-5000 in solar units within the half-light radius, making them critical tests for cosmological models. However, it is a concern whether the…

Using photometry and spectroscopy of 144,609 galaxies from the Sloan Digital Sky Survey, we present bivariate distributions of pairs of seven galaxy properties: four optical colors, surface brightness, radial profile shape as measured by…

We carried out a radial velocity survey for spectroscopic binaries in the low density globular cluster NGC5053. Our sample contains a total of 77 cluster member giant and subgiant stars with visual magnitudes of 14.5-18.6. Of these 77…