Baryons in the Intergalactic Medium: A Hubble Spectroscopic Legacy Archive Search

Galaxies are not closed systems but are constantly interacting with their environment which generally contains a) other nearby galaxies and b) some form of warm gaseous medium existing between galaxies (known as the Intergalactic Medium or IGM). As a result, a number of physical mechanisms exist to liberate baryons (stars and gas) from within a galaxy and transfer them to the IGM. Currently there is a well-documented “missing baryon” problem in Cosmology as known galaxies do not contain enough baryons to be consistent with Big Bang Cosmology. This implies a substantial amount of Baryons must exist in the IGM, but most of this remains undetected. Using absorption in Quasar (QSO) spectra from the Hubble Spectroscopic Legacy Archive (HSLA) we can detect individual species present in the IGM. In this work, I build up and refine a pipeline to analyze 688 QSO spectra from the HSLA. At the end of the pipeline, there are multiple possible species identifications for each absorption feature. Looking at models for the extremes of the possible absorptions puts bounds that between 1.6% and 48% of the total baryon density from Big Bang Cosmology can be found in extragalactic clouds. These results do not solve the Missing Baryon Problem, but do provide evidence that baryons liberated from galaxies could be part of the complete solution. This dissertation includes previously unpublished co-authored material.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Department of Physics

Grantor dc:publisher

University of Oregon

Year dc:date.issued

2022

Author dc:creator

• Brunnenmeyer, Trevor

Advisor dc:contributor.advisor

• Bothun, Greg

Statement dc:rights

• All Rights Reserved.

Language dc:language.iso

en_US

Handle dc:identifier.uri

https://hdl.handle.net/1794/27572

OAI record oai:identifier

https://scholarsbank.uoregon.edu/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Ascholarsbank.uoregon.edu%3A1794%2F27572