We present the first results of a comprehensive HST study of the star-formation history of Fornax dSph, based on WFPC2 imaging of 7 Fornax fields. Our observations reach the oldest main-sequence turnoffs, allowing us to address fundamental questions of dwarf galaxy evolution, such as the spatial variations in the stellar content, and whether the

A comparison is carried out among the star formation histories of early-type galaxies in fossil groups, clusters and low density environments. Although they show similar evolutionary histories, a significant fraction of the fossils are younger than their counterparts, suggesting that they can be precursors of the isolated ETG galaxies.

This is the second of two papers presenting a detailed long-slit spectroscopic study of the stellar populations in a sample of 36 ultraluminous infrared galaxies (ULIRGs). In the previous paper, we presented the sample, the data and the spectral synthesis modelling. In this paper, we carry out a more detailed analysis of the modelling results, with

Searches for planets around massive stars are essential for developing general understanding of planet formation and evolution of planetary systems. The main objective of the PSU-TCfA Search for Planets around Evolved Stars is detection of planets around G-K subgiants and giants through highly accurate radial velocity (RV) measurements using an

The NIR Ca ii triplet absorption lines have proven to be an important tool for quantitative spectroscopy of individual red giant branch stars in the Local Group, providing a better understanding of metallicities of stars in the Milky Way and dwarf galaxies and thereby an opportunity to constrain their chemical evolution processes. An interesting

Context. Very few examples of luminous blue variable (LBV) stars or LBV candidates (LBVc) are known, particularly at metallicities below that of the Small Magellanic Cloud (SMC). The LBV phase is known to be crucial for the evolution of massive stars, and its behavior with metallicity is very poorly known. Variable star V39 in IC 1613 is a well