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Full-Text Articles in External Galaxies
The Evolution Of X-Ray Binaries And Their Accretion States, Lacey A. West
The Evolution Of X-Ray Binaries And Their Accretion States, Lacey A. West
Graduate Theses and Dissertations
X-ray binary systems (XRBs) consist of a compact object component (e.g., black hole or neutron star) that accretes matter from a companion star. Although the extent to which XRBs contributed to the early heating of the intergalactic medium is still under investigation, it is estimated that XRBs dominated the X-ray radiation field before the reionization epoch. The study of XRB emission is therefore crucial to our understanding of the very early universe. Furthermore, studying the abundance and radial distribution of each XRB type within a galaxy can be revealing of the host galaxy’s local properties, structure, and evolution. XRB spectra …
Testing Spiral Density-Wave Theory In Disk Galaxies Using Multi-Wavelength Image Data, Star Formation History Maps And Spatially Resolved Stellar Clusters, Mohamed Shameer Abdeen
Testing Spiral Density-Wave Theory In Disk Galaxies Using Multi-Wavelength Image Data, Star Formation History Maps And Spatially Resolved Stellar Clusters, Mohamed Shameer Abdeen
Graduate Theses and Dissertations
Studying galaxy structures using different wavebands enables us to observe a varietyof intrinsic galactic features and to test the validity of underlying theories in detail. Density wave theory, originally proposed by C.C. Lin and F. Shu (Lin & Shu 1964), explains the nature of the spiral arm patterns in disk galaxies as density waves that propagate through the galactic disk. From spiral galaxies to the rings of Saturn, density wave theory has had success in providing qualitative explanations of disk dynamics. However, it is now widely believed that galactic disks are dissipative systems which raises the question of whether they …
Energy From Active Galactic Nuclei And The Effects On Host Spiral Galaxies, Amanda Schilling
Energy From Active Galactic Nuclei And The Effects On Host Spiral Galaxies, Amanda Schilling
Graduate Theses and Dissertations
I have investigated the energy output of active galactic nuclei (AGN) in order to understand how these objects evolve and the impact they may have on host galaxies. First, I looked at a sample of 96 AGN at redshifts $z \sim 2, 3,$ and $4$ which have imaging and thus luminosity measurements in the $griz$ and $JHK$ observed wavebands. For these galaxies, I have co-epochal data across those bands which accounted for variability in AGN luminosity. I used the luminosity measurements in the five bands to construct spectral energy distributions (SED) in the emitted optical-UV bands for each AGN. I …