Intergalactic baryon enrichment and implications for galaxy evolution at high redshift
Name
1079908197-MIT.pdf
Description
Full printable version
Size
25.12 MB
Format
Adobe PDF
Checksum (MD5)
e032c7055e523e14320ea0b4abb85815
Author(s)
Cooper, Thomas (Thomas J.), Ph. D. Massachusetts Institute of Technology
Advisor(s)
Robert A. Simcoe.
Date Issued
2018
Publisher
Massachusetts Institute of Technology
Abstract
In this thesis we present several surveys of heavy element absorber characteristics at high redshift, gauging properties of diffuse intra- and intergalactic gas in the first several Gyr of the Universe. At z ~ 3.5, we study chemical abundances of Lyman limit systems (LLSs) and evaluate their potential to represent expected reservoirs of cold, low-metallicity gas whose accretion onto galaxies is necessary to maintain star formation. In an initial survey focused only on LLSs identified as potential lowmetallicity absorbers, based on the absence of metal lines in low-resolution spectra, we indeed found the selected systems have low abundances, with a median of [M/H]~ -2.2 and several systems at [M/H]/~ 6, we find that the bulk of high-redshift absorption systems are low-ionization and low-metallicity. Since H i absorption cannot be seen at z >/~ 6, we further argue from incidence rates and absorber characteristics that these absorbers are analogous to strong neutral hydrogen systems seen at lower redshift. We conclude that the non-detection of weaker H i absorption systems (such as LLSs) is consistent with lower metallicities and lower ionization states in the circumgalactic medium than is seen at later times.
Description
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 187-194).
Subjects
Physics.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.
Persistent DSpace Link
