“Synthesizing Absorption-Line Spectra of a Simulated Circumgalactic Cloud”

Abstract: The circumgalactic medium (CGM) is a multi-phase gas halo around galaxies. It is a major focus of galaxy evolution research because it regulates star formation and the overall gas supply of galaxies. The CGM is studied by means of absorption-line spectroscopy in which quasars are used as bright background point sources that allow astronomers to observe the gas along a single line-of-sight. However, due to the rarity of quasars and to instrumental limitations, observational data is difficult to interpret. Thus, hydrodynamic simulations are vital for our understanding of the CGM, for the provide a controlled environment. In this project, I perform mock observations along multiple sightlines of a cool ionized cloud simulated from the hydrodynamics code, CHOllA, and analyze their respective absorption-line spectra to find constraints that may facilitate the interpretation of observational data. I study how these lines vary through space and at different gas temperatures, densities, and abundances. Additionally, I make mock comparisons to observational data by comparing the structure of a given line computed at an unrealistically high resolution to that of a line simulated with the resolution of a Cosmic Origins Spectrograph (COS) instrument.

This $4,000 tuition scholarship is awarded annually to an undergraduate major in the Department of Physics and Astronomy in memory of our student, Emil Sanielevici (1979-2000), whose enthusiasm and love of scientific research continue to inspire us all. Each year, the winner of the award will present their research in a short seminar such as this one.

Watch our News Section for when the 2023-24 Scholarship Application Opens!