MgII Absorbers: Disks, Halos, Satellites, and Pairs?

Abstract

To understand which parts of galaxies give rise to the variety of observed MgII absorption profiles seen in QSO spectra, we have embarked upon a program to generate simulated absorption profiles as they would arise from the many typical galactic structures we see today. Here, we present preliminary results for a clumpy, rotating disk which has been sampled by a variety of QSO lines of sight. The resulting ensemble of simulated profiles is qualitatively similar to those observed in HIRES spectra of 0.4 < z < 1.0 MgII systems (Churchill, this volume). Additionally, we discuss the statistical contribution from satellite galaxies, which would be expected to contribute additional absorption subcomponents and are likely to have been more numerous at intermediate redshifts. Our preliminary finding is that the common disk and satellite components of galaxies may, to a large degree, be the structures giving rise to a variety of the observed MgII absorption profiles.