Description
TitleThe evolution of neutral gas in star-forming galaxies across cosmic time
Date Created2014
Other Date2014-05 (degree)
Extentxiii, 227 p. : ill.
DescriptionWe study the evolution of cold gas in distant galaxies by analyzing observations, semi-analytic models (SAMs), and simulations of star-forming galaxies (SFGs) and damped Lyα absorption systems (DLAs). First, we present individual and composite rest-frame ultraviolet (UV) spectra for 81 SFGs where we study the relations among Lyα emission, low and high ionization absorption strength, rest-ultraviolet continuum slope, redshift, and velocity offset. We find that galaxies with R < 25.5 and W_Lyα > 20A have bluer UV continua, weaker low-ionization interstellar absorption lines, weaker C IV absorption, and stronger Si II nebular emission than those with W_Lyα < 20A. Next, we present our range of models which include “standard,” “extended,” and merger-based disks as well as a metallicity-dependent and pressure-based prescription for partitioning cold gas into atomic and molecular components. Using these models, we “observe” a catalog of mock DLAs, which we compare to observations. We find that extended disk models reproduce quite well the column density distribution of absorbers over the column density range 19 < log N(HI) < 22.5, the observed line density of DLAs, Hi gas density, the ∆v distribution in the redshift range 2 < z < 3.5, and the evolution of DLA metallicity with redshift. Using these models, we characterize the properties of DLA host galaxies and compare them to model SFGs “observed” in the SAMs. We show that DLA host galaxies exhibit a broad range of galaxy properties spanning several decades in stellar mass, star formation rate, and luminosity and fall upon common galaxy scaling relations. Finally, we analyze the radial profiles and evolution of 15 galaxies in numerical simulations and compare them to predictions from the SAMs. Galaxies’ cold gas and stellar components are moderately well-fit by exponential profiles, although both gas partitioning recipes predict more molecular gas and less star formation than is observed in the numerical simulations. Nonetheless, both types of simulations predict similar evolution in galaxy properties from z = 2 to z = 0.
NotePh.D.
NoteIncludes bibliographical references
Noteby Michael James Berry
Genretheses, ETD doctoral
Languageeng
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.