All ETDs from UAB

Advisory Committee Chair

Jimmy Irwin

Advisory Committee Members

Robert Mohr

Preethi Nair

Mary Ellen Zvanut

Clayton Simien

Document Type


Date of Award


Degree Name by School

Doctor of Philosophy (PhD) College of Arts and Sciences


Hot gas characteristic to early-type galaxies (ETG) has been well-studied; this hot gas is the result of high velocity dispersions intrinsic to galaxies with low net angular momentum, in conjunction with stellar mass loss of highly-evolved red giant stars. Accordingly, one would expect the extent of these hot gas halos to trace very well with stellar mass, which is typically calculated with tightly-constrained mass-to-light ratios in the infrared K-band. However, ETGs exhibit a large dispersion between their X-ray hot gas luminosities and their K-band luminosities, indicating that the presence of ETG hot gas halos is only loosely related to their stellar masses. Examination of these galaxies’ surface (areal) stellar mass density has revealed this as a possible parameter that traces hot gas retention. Examined here are members of two NIR catalogues, which allow for density calculations of ETGs with Chandra data in the K-band: the very local Atlas3D (distance < 43 Mpc) contributes 49 galaxies of various luminosities and environments, and MASSIVE contains 45 ETGs selected in the original survey for their high masses (distance < 108 Mpc). Outlined here is a Chandra archival study of these galaxies, which span various galaxy environments, to determine X-ray/optical emission ratios as well as examine the stellar mass density dependence of the LX / LK dispersion in these galaxies—and thus their ability to retain hot gas.