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Intergalactic mergers and starbursts and their role in galaxy evolution

Posted on:2006-11-22Degree:Ph.DType:Dissertation
University:The University of Wisconsin - MadisonCandidate:Wehner, Elizabeth MarieFull Text:PDF
GTID:1450390008457215Subject:Physics
Abstract/Summary:
We present results from several research projects designed to explore star formation in galaxies and to better define the role that intense star formation and intergalactic mergers play in driving galaxy evolution. In Chapter 2 we examine the star formation histories of 1,200 galaxies in the local universe to determine the age of their stellar populations. We find a factor of approximately five increase in the amount of star formation from z≲ 0.4 to z≳0.4 .; In Chapter 3 we explore the star forming properties of Extremely Red Objects (EROs) and find them to be significant sources of submillimeter emission, indicating the presence of dust-enshrouded star formation. We also find that these systems constitute a significant fraction (up to 61%) of the extragalactic background light in the submillimeter.; In Chapters 4, 5, and 6, we examine starburst galaxies in the local ( z < 3, 000 km/s) universe. We discovered a closed tidal loop surrounding the starburst galaxy, NGC 3310. We find an upper limit of the HI gas in the loop to be on the order of 107M⊙ , and we estimate its stellar mass content to be ∼4 x 10 8 M⊙ . We also find that the shell-like stellar debris surrounding this system is not consistent with having originated in NGC 3310's own disk, supporting the idea that this system was created during the collision of two equal mass, gas rich galaxies. We find that the surface brightness profile for this galaxy follows the R1/4 law; however the Halpha emission indicates the presence of a young, rotating disk. While this system has recently undergone a major collision, it appears to be in the process of forming a new stellar disk.
Keywords/Search Tags:Star, Galaxy, Galaxies, Stellar
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