University of Pennsylvania ScholarlyCommons Publicly Accessible Penn Dissertations 2016 High Redshift Galaxies As Probes Of The Epoch Of Reionization Jessie Frances Taylor University of Pennsylvania,
[email protected] Follow this and additional works at: https://repository.upenn.edu/edissertations Part of the Astrophysics and Astronomy Commons, and the Physics Commons Recommended Citation Taylor, Jessie Frances, "High Redshift Galaxies As Probes Of The Epoch Of Reionization" (2016). Publicly Accessible Penn Dissertations. 2603. https://repository.upenn.edu/edissertations/2603 This paper is posted at ScholarlyCommons. https://repository.upenn.edu/edissertations/2603 For more information, please contact
[email protected]. High Redshift Galaxies As Probes Of The Epoch Of Reionization Abstract Following the Big Bang, as the Universe cooled, hydrogen and helium recombined, forming neutral gas. Currently, this gas largely resides between galaxies in a highly diffuse state known as the intergalactic medium (IGM). Observations indicate that the IGM, fueled by early galaxies and/or accreting black holes, ``reionized'' early in cosmic history--the entire volume of the Universe refilling with ionized gas. This thesis analyzes and develops several ways to use observations of high redshift galaxies to probe this period, the Epoch of Reionization (EoR). We examine the redshift evolution of the Ly-alpha fraction, the percentage of Lyman-break selected galaxies (LBGs) that are Lyman-alpha emitting galaxies (LAEs). Observing a sharp drop in this fraction at z ~ 7, many early studies surmised the z ~ 7 IGM must be surprisingly neutral. We model the effect of patchy reionization on Ly-alpha fraction observations, concluding that sample variance reduces the neutral fraction required.