David S. Davis

Research Interests

My work primarily concerns the study of large-scale structure and determination of physical constraints on cosmological models by analyzing X-ray data on some of the best tracers of large-scale structure, clusters and groups of galaxies. I am also interested in the structure and evolution of elliptical galaxies. Specifically, how their environment affects the correlations between the global X-ray and optical properties and the enrichment process for the hot diffuse gas.

I am currently involved in analyzing the X-ray imaging data of Abell 2255 from the CXO with Dr. R. E. White III. This cluster shows evidence of merger activity from the ROSAT and ASCA data. This evidence includes elliptical isophotes, twisted isophotes, and temperature structure in the X-ray data. We are examining this cluster in detail with the higher resolution Chandra data. I am also working with Dr. Jim Rose analyzing the Chandra data for Abell 3158, a cluster which shows a clumpy X-ray morphology, a clumpy distribution of galaxies, and galaxy peaks that are offset from the X-ray peaks, all strong evidence for a recent merger.

I am also actively involved in determining the properties of poor groups of galaxies. These groups are low mass and thus collapse at later times than more massive clusters. Using ROSAT and ASCA data we have obtained the spectral and spatial properties of a large sample of poor groups. Currently, we are using XMM and optical data to study these groups in more detail and provide spatially resolved spectra to better determine their temperature and abundance structure. This will allow us to better compare these poor systems with theoretical predictions of their structure and formation.

I am also analyzing Chandra data for elliptical galaxies. Using a magnitude-limited sample of elliptical galaxies we have selected galaxies that show anomalously low metal abundance. Using the high spatial resolution of the Chandra data we can determine the metal abundance on approximately the same spatial scale that the optical abundances are measured. Comparing these two datasets will allow us to test models for the enrichment of diffuse gas component in much more detail than has been previously possible.