We study the formation of 53 galaxy cluster-size dark matter halos (M = 1014.0-14.76 M sun) formed within a pair of cosmological Λ cold dark matter N-body simulations, and track the accretion histories of cluster subhalos with masses large enough to host ~0.3 L * galaxies. By associating subhalos with cluster galaxies, we find the majority of

We have used observations obtained as part of the Hubble Space Telescope/ACS Survey of Galactic globular clusters (GCs) to construct a color-magnitude diagram for the bulge cluster, NGC 6366. The luminosity function derived from those data extends to M F606W ~ 9, or masses of ~0.3 M sun. Unlike most GCs, the mass function peaks near the main

The Advanced Camera for Surveys (ACS) Nearby Galaxy Survey Treasury is a large Hubble Space Telescope (HST)/ACS treasury program to obtain resolved stellar photometry for a volume-limited sample of galaxies out to 4 Mpc. As part of this program, we have obtained deep ACS imaging of a field in the outer disk of the large spiral galaxy M81. The field

Aims: We present a new method that investigates the evolutionary history of the pulsating DB white dwarf GD 358 using asteroseismology. This is done considering the internal C/O profile, which describes the relative abundances of carbon and oxygen from the core of the star to its surface. Different evolutionary channels lead to the generation of

Context: Evolution of galaxies through cosmic time has been widely studied at high redshift, but there are a few studies in this field at lower redshifts. However, low-redshifts studies will provide important clues to the evolution of galaxies, furnishing the required link between local and high-redshift universe. Aims: In this work we focus on the

The presence of surface convection in K-type dwarfs is revealed in very high quality spectra of nine bright stars. The observed asymmetries and wavelength shifts of the Fe I absorption line profiles are mainly due to granulation. The bisectors of the strongest Fe I lines have a span of about 100 m/s and the central wavelengths of the weakest Fe I