Probing the epoch of reionization

Griffiths, Alex (2021) Probing the epoch of reionization. PhD thesis, University of Nottingham.

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Abstract

The first generation of stars and galaxies are formed under gravitational collapse due to perturbations seeded from quantum fluctuations in the early Universe. These sources emit ionizing radiation, carving out ionized regions of the neutral intergalactic medium. With the subsequent formation and evolution of these primordial systems, ionized regions expand and overlap such that they eventually permeate throughout the entire universe, bringing an end to the dark ages and ushering in the epoch of reionization. Despite its pivotal role, the epoch of reionization lies mostly beyond the current observational capabilities and as such, is one of the least understood periods in the history of the Universe.

The work in this thesis aims to address some of the fundamental questions regarding the epoch of reionization. Primarily investigating how current state-of-the-art facilities can push the observational frontier in the search for the first galaxies, and in the identification of low redshift analogues of the galaxies thought to play a prominent role in the reionization of the Universe.

At high redshifts, this investigation implements the unique phase space of compact, massive galaxy clusters in the search for the first galaxies. These clusters couple strong lensing potential with low levels of intracluster light, crucial for the identification of high redshift gravitationally lensed galaxies. Further, the utility of integral field observations for the identification and analysis of high redshift sources is explored. Through the design and implementation of a novel spectral extraction algorithm, sources can be successfully deblended from nearby contaminants while sufficiently increasing spectral signal-to-noise. At low redshifts, this work explores SHARDS medium-band imaging of two Frontier Field clusters for the identification of faint, low-mass dwarf galaxies, analogues of the objects believed to play a leading role in the reionization of the universe.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Conselice, Christopher
Keywords: Cosmogony, Epoch of reionization, Ionized regions
Subjects: Q Science > QB Astronomy
Faculties/Schools: UK Campuses > Faculty of Science > School of Physics and Astronomy
Item ID: 64399
Depositing User: Griffiths, Alex
Date Deposited: 22 Mar 2021 14:31
Last Modified: 22 Mar 2021 14:45
URI: http://eprints.nottingham.ac.uk/id/eprint/64399

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