Dissertation/Thesis Abstract

The space density, environments, and physical properties of large Lyα nebulae
by Prescott, Moire Kathleen Murphy, Ph.D., The University of Arizona, 2009, 199; 3369688
Abstract (Summary)

Powerful forces are at work in giant Lyα nebulae, a rare and mysterious population in the high redshift universe. Much like the spatially extended emission line halos around high redshift radio galaxies—but without the strong radio emission—Lyα nebulae (or Lyα 'blobs') boast copious Lyα emission (1044 erg s -1), large sizes (∼100 kpc), complex gas morphologies, and the company of numerous compact, star-forming galaxies, and may offer a window into dramatic episodes of massive galaxy formation. The small sample sizes and complex inner workings of Lyα nebulae have limited progress on understanding the their space density, environments, and physical conditions. This thesis strives to answer fundamental questions about Lyα nebulae and pave the way for understanding their role in the build up of massive galaxy systems. To address the frequency of collapse of these massive structures, we carried out the largest systematic Lyα nebula survey to date and measured the Lyα nebula space density. As an unbiased test of the environment of Lyα nebulae, we studied the surroundings of a Lyα nebula and confirmed that Lyα nebulae reside preferentially in overdense regions. To disentangle the sources of ionization, we took a census of all the compact ionization sources within a large Lyα nebula using high resolution imaging. Finally, we used photoionization modeling to put constraints on the physical conditions, the metallicity, and the sources of ionization within Lyα nebulae. Future work will be able to build on this thesis by expanding the systematic search for Lyα nebulae to other existing deep broad-band datasets, mapping the three-dimensional overdense structures in which Lyα nebulae live out to ≥50 (comoving) Mpc scales, and disentangling multiple sources of ionization within a larger sample of individual systems using deep optical and near-infrared spectroscopy and detailed photoionization modeling.

Indexing (document details)
Advisor: Davé, Romeel, Dey, Arjun
Commitee: Green, Richard, Impey, Chris, Thompson, Rodger
School: The University of Arizona
Department: Astronomy
School Location: United States -- Arizona
Source: DAI-B 70/08, Dissertation Abstracts International
Subjects: Astronomy
Keywords: Galaxy formation, High redshift galaxies, Space density
Publication Number: 3369688
ISBN: 978-1-109-32133-3
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