The optical and H I properties for a sample of low surface brightness (LSB) dwarf galaxies, cataloged from the Second Palomar Sky Survey, is presented. Gas mass fractions for LSB dwarfs reach the highest levels of any know galaxy type (fg =95%) confirming that their low stellar densities are due to inefficient conversion of gas mass into stellar mass. Comparison with star formation models indic...

A significant fraction of nearby elliptical galaxies are known to have high-density gas disks in their circumnuclear (CN) region (0.1 to a few kpc). Yet, ellipticals, especially luminous ones, show little signs of recent star formation. To investigate the possible cause of the dearth of star formation in these systems, we study the gravitational stability of CN gas disks embedded within the gra...

Over the past years observations of young and populous star clusters have shown that the stellar IMF appears to be an invariant featureless Salpeter power-law with an exponent α = 2.35 for stars more massive than a few M⊙. A consensus has also emerged that most, if not all, stars form in stellar groups and star clusters, and that the mass function of young star clusters in the solar-neighborhoo...

Local Group galaxies such as the Milky Way, the Magellanic Clouds and M31 are being used by a number of international collaborations to search for microlensing events. Type and number of detections place constraints on dark matter and the stellar populations within and along the line of sight to these galaxies. In this review I briefly discuss the stellar populations, evolutionary histories, an...

Hot gas dominates the emission in X-ray luminous early-type galaxies, but in relatively X-ray faint systems, integrated X-ray emission from discrete stellar-like sources is thought to be considerable, although the amount of the contribution is controversial. To help resolve this issue, we examine the radial X-ray surface brightness distribution of 17 X-ray faint galaxies observed with the ROSAT...

The high-redshift (z>2) galaxies discovered over the last few years with the Lyman-break technique represent, in number density, a major fraction of the galaxies known in the Local Universe. Thus, understanding the properties and the nature of these high-redshift systems is instrumental to our understanding of the cosmic evolution of galaxies and their stellar content. I briefly review the obse...

We present near-infrared K-band spectroscopy of 21 elliptical or cD Brightest Cluster Galaxies (BCGs), for which we have measured the strength of the 2.293 µm CO stellar absorption feature. We find that the strength of this feature is remarkably uniform among these galaxies, with a smaller scatter in equivalent width than for the normal elliptical population in the field or clusters. The scatte...