Related papers: The Subdwarf Luminosity Function
We derive an accurate mass estimator for dispersion-supported stellar systems and demonstrate its validity by analyzing resolved line-of-sight velocity data for globular clusters, dwarf galaxies, and elliptical galaxies. Specifically, by…
Low-mass satellites around Milky Way (MW)-like galaxies are important probes of small scale structure and galaxy formation. However, confirmation of satellite candidates with distance measurements remains a key barrier to fast progress in…
(abridged) We apply the Jeans equation to estimate masses for eight of the brightest dSph galaxies. For Fornax we obtain a model-independent constraint on the maximum-circular velocity, Vmax=18_{-3}^{+5} km/s. Although we obtain only…
White dwarfs are the fossils left by the evolution of low-and intermediate-mass stars, and have very long evolutionary timescales. This allows us to use them to explore the properties of old populations, like the Galactic halo. We present a…
We study a sample of about 1400 disk M dwarfs that are found in 148 fields observed with the Wide Field Camera 2 (WFC2) on the Hubble Space Telescope and 162 fields observed with pre-repair Planetary Camera 1 (PC1), of which 95 of the WFC2…
We develop a flexible set of action-based distribution functions (DFs) for stellar haloes. The DFs have five free parameters, controlling the inner and outer density slope, break radius, flattening and anisotropy respectively. The DFs…
We identified 46 unresolved source candidates in the Hubble Ultra Deep Field, down to i775 = 29.5. Unresolved objects were identified using a parameter S, which measures the deviation from the curve-of-growth of a point source. Extensive…
We use a new technique to search for faint red stars in the Hubble Deep Field (HDF) imaged by the Wide Field Camera (WFC2) on the {\it Hubble Space Telescope}. We construct a densely sampled stellar light profile from a set of undersampled…
We show that measuring the proper motion of ${{\sim 2000}}$ stars within a dwarf galaxy, with an uncertainty of 1 km/s at most, can establish whether the Dark Matter (DM) density profile of the dwarf has a central core or cusp. We derive…
We present an approximation for the average density profile of dark matter haloes in the LambdaCDM cosmological model, which is accurate to within 10--15% even for large radial distances from 0.05R_{vir} up to 10R_{vir} for halo masses…
The dark halo substructures predicted by current cold dark matter simulations may in principle be detectable through strong-lensing image splitting of quasars on small angular scales (0.01 arcseconds or below). Here, we estimate the overall…
Near-infrared properties of 451 galaxies with distances D \leq 10 Mpc are considered basing on the all-sky two micron survey (2MASS). A luminosity function of the galaxies in the K-band is derived within [-25,-11] mag. The local (D < 8 Mpc)…
Parallaxes, proper motions, and optical photometry are presented for 51 systems made up 37 cool subdwarf and 14 additional high proper motion systems. Thirty-seven systems have parallaxes reported for the first time, 15 of which have proper…
We present a catalog of 9316 spectroscopically confirmed white dwarfs from the Sloan Digital Sky Survey Data Release 4. We have selected the stars through photometric cuts and spectroscopic modeling, backed up by a set of visual…
We detect the weak gravitational lensing distortion of 450,000 background galaxies (20<R<23) by 790 foreground galaxies (R<18) selected from the Las Campanas Redshift Survey (LCRS). This is the first detection of weak lensing by field…
The SDSS Data Release 1 includes 1833 DA white dwarfs (WDs) and forms the largest homogeneous sample of WDs. This sample provides the best opportunity to study the statistical properties of WDs. We adopt a recently established theoretical…
Bivariate luminosity functions (LFs) are computed for galaxies in the New York Value-Added Galaxy Catalogue, based on the Sloan Digital Sky Survey Data Release 4. The galaxy properties investigated are the morphological type, inverse…
We determine the 22$\mu$m luminosity evolution and luminosity function for quasars from a data set of over 20,000 objects obtained by combining flux-limited Sloan Digital Sky Survey optical and Wide field Infrared Survey Explorer…
We present the mass distribution for all S/N > 15 pure DA white dwarfs detected in the Sloan Digital Sky Survey up to Data Release 12, fitted with Koester models for ML2/alpha=0.8, and with Teff > 10 000 K, and for DBs with S/N >10, fitted…
The observed flaring of HI disk in the outer region of galaxies has been used in the past to determine the shape of the dark matter halo. Previous studies based on this concept suggest a slightly oblate halo (axis ratio ~ 0.8) for our…