We present the first results from our survey of stellar substructure in the outskirts of M31 using the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope. We discuss the stellar populations associated with five prominent stellar overdensities discovered during the course of our panoramic ground-based imaging survey with the Isaac Newton Telescope Wide-Field Camera (INT WFC); ...

Old starburst galaxies are deficient in O stars, and hence do not exhibit strong line emission in the optical regime. However, there remain many B stars, which are expected to heat dust grains and generate strong continuum emission in the far-infrared. The IRAS data for a statistically complete sample of nearby galaxies reveal for the first time that such objects are as numerous as 30–40% of th...

We present stellar mass measurements for a sample of 36 luminous compact blue galaxies (LCBGs) at redshifts in the flanking fields around the Hubble Deep Field–North. The technique is based on fitting a twoz p 0.4–1.2 component galaxy population model to multi-broadband photometry. Best-fit models are found to be largely independent of the assumed values for the initial mass function (IMF) and ...

We have measured Lick index equivalent widths to derive luminosity weighted stellar ages and metallicities for thin and thick disk dominated regions of 9 edge-on disk galaxies with the ARC 3.5 meter telescope at Apache Point Observatory. In all cases, the thick disks are confirmed to be old stellar populations, with typical ages between 4 and 10 Gyr. The thin disks are uniformly younger than th...

I review the relationship between star formation and black hole building, based on spectroscopic observations of the stellar population in active galactic nuclei (AGNs) and their host galaxies. My emphasis is on large, well-defined local samples of AGNs, whose optical continua are dominated by starlight. I summarize the spectroscopic tools used to characterize their stellar content. Surveys of ...

We study the evolution of Lyman Break Galaxies (LBGs) from z = 5 to z = 0 by tracing the merger trees of galaxies in a large-scale hydrodynamic simulation based on a Λ cold dark matter model. In particular, we emphasize on the range of properties of the sample selected by the rest-frame V band luminosity, in accordance with recent near-IR observations. The predicted rest-frame V band luminosity...

We have obtained low resolution spectra of nineteen red and blue low surface brightness galaxies, using the Marcario Low Resolution Spectrograph on the 9.2m Hobby-Eberly Telescope. These galaxies form a very heterogeneous class, whose spectra qualitatively resemble those of high surface brightness galaxies covering the full range of spectra seen in galaxies of Hubble types from E to Irr. We use...