Inter[stellar and galactic] Medium Program of Studies (IMPS)
at UC Santa Cruz/Lick Observatory

Enrichment of the ISM: Stellar Mass Loss White dwarf imaging and spectroscopy in star clusters reveals the total integrated mass loss that stars suffer through post-main sequence evolution. The initial-to-final mass relation therefore represents a powerful input to chemical evolution models of galaxies (including enrichment of the interstellar medium) and therefore enhances our understanding of star formation efficiencies in these systems.

GRB/ISM: Gas and Metals GRB afterglow spectroscopy reveals the HI column density of the gas surrounding the GRB via analysis of the Lya profile. Similarly, analysis of metal-line transitions constrain the metallicity, depletion level, kinematic characteristics, and distance of the observed gas.

GRB/IGM: MgII A simple accounting of the number of strong (EW > 1Ang) MgII absorbers along GRB sightlines shows a surprising excess relative to SDSS quasar sightlines. Although the GRB sample is small (fewer than 20 sightlines), the statistical significance is high (less than 1 in 10,000 chance probability). All the more troubling is that all 'reasonable' explanations have not held up.

z~3 IGM It has been known for about a decade that the intergalactic medium at z ~ 3 is enriched with carbon and other metals even to quite low cosmic densities. These measurements are made possible by strong CIV, SiIV, and OVI metal lines that fall into the optical when emitted from z ~ 1-4, and can be measured with exquisite precision by Keck HIRES, VLT UVES, and other spectrographs. Most stellar mass formed in in the redshift range z ~ 1-4, and by observing the IGM at this time we can both learn about the dynamics of galaxies and galaxy outflows during this epoch, but also measure a fossil record of star and galaxy formation at higher redshift. The UCSC group continues work in determining the abundance and distribution of these elements, and comparing them to simulations and analytic models to assess their import for a variety of questions regarding the high-z universe.