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Astrophysics and Astronomy

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University of Arkansas, Fayetteville

Theses/Dissertations

Galaxies

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Articles 1 - 4 of 4

Full-Text Articles in Physical Sciences and Mathematics

The Cosmic History Of X-Ray Binary Evolution, Woodrow Gilbertson Aug 2022

The Cosmic History Of X-Ray Binary Evolution, Woodrow Gilbertson

Graduate Theses and Dissertations

The Chandra Deep Fields provide an extraordinary window into the high-energy history of the cosmos. Observations of non-active galaxies within the deep fields can be leveraged to extract information about the formation and evolution of X-ray binaries (XRBs). Previous studies have suggested that the evolution of XRB luminosity can be expressed a function of physical parameters such as star formation rate, stellar mass, stellar age, and metallicity. The goal of this work is to develop and implement a complete physical parameterization for the luminosity of XRB populations, which can be utilized for a variety of further studies.

Chapter 1 provides …


An Upper Limit On The Tightening Of Galactic Spiral Arm Pitch Angle In Cosmic Time, Douglas William Shields Aug 2017

An Upper Limit On The Tightening Of Galactic Spiral Arm Pitch Angle In Cosmic Time, Douglas William Shields

Graduate Theses and Dissertations

We present Spirality, a novel method of measuring pitch angle by fitting galaxy images to spiral templates of known pitch. Using this algorithm in concert with 2-dimensional Fast Fourier Transform (2DFFT), we determined that the pitch angle of the redshift 2.011 galaxy GZ5001 (J2000 RA 189.14811 degrees, Dec 62.24002 degrees) is approximately (16.2 +/- 2.6) degrees. The redshift 2.3219 galaxy GS21 (J2000 RA 53.14863 degrees, Dec -27.95469 degrees), which is believed to be the most distant galaxy with visible spiral structure yet measured, has a pitch of approximately (-10.6 +/- 1.6) degrees. Using a large sample of galaxies from the …


Dark Matter Halo Concentration And The Evolution Of Spiral Structure In N-Body, Barred Spiral Galaxies, Jazmin Esmeralda Berlanga Medina Dec 2015

Dark Matter Halo Concentration And The Evolution Of Spiral Structure In N-Body, Barred Spiral Galaxies, Jazmin Esmeralda Berlanga Medina

Graduate Theses and Dissertations

Motivated by the evidence of relationships between pitch angle (the tightness of spiral arm structure in the disk), P, and various indicators of central mass concentration, as well as the theoretical relationship between halo mass concentration and the density of visible matter in the central part of the galaxy, we look at a possible relationship between P and cvir (the virial concentration of the dark matter halo) in N-body simulations of barred, spiral galaxies. We also look at the evolution of pitch angle over time in higher temporal resolution than any data currently available in the literature. We find that …


Active Galactic Nuclei Mergers And Outflows: Observations From Optical And Ultraviolet Emission Lines, Robert Scott Barrows May 2013

Active Galactic Nuclei Mergers And Outflows: Observations From Optical And Ultraviolet Emission Lines, Robert Scott Barrows

Graduate Theses and Dissertations

I have investigated the nature of a subset of active galactic nuclei (AGN) which show double peaks in their characteristic optical and ultraviolet emission lines. I have performed this investigation through studies of the broad emission line regions (BLRs), which are produced less than 1 pc from the central supermassive black hole (SMBH), and the narrow emission line regions (NLRs), which originate at larger (kpc) distances. The BLR studies consist of detailed line modeling of two individual quasars with double-peaked broad emission line profiles. The modeling suggests there are two primary interpretations of the complex broad line profiles. The first …