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- All Subjects: Star Formation
- Member of: Theses and Dissertations
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
This work examines star formation in the debris associated with collisions of dwarf and spiral galaxies. While the spectacular displays of major mergers are famous (e.g., NGC 4038/9, ``The Antennae''), equal mass galaxy mergers are relatively rare compared to minor mergers (mass ratio <0.3) Minor mergers are less energetic than major mergers, but more common in the observable universe and, thus, likely played a pivotal role in the formation of most large galaxies. Centers of mergers host vigorous star formation from high gas density and turbulence and are surveyed over cosmological distances. However, the tidal debris resulting from these mergers have not been well studied. Such regions have large reservoirs of gaseous material that can be used as fuel for subsequent star formation but also have lower gas density. Tracers of star formation at the local and global scale have been examined for three tidal tails in two minor merger systems. These tracers include young star cluster populations, H-alpha, and [CII] emission. The rate of apparent star formation derived from these tracers is compared to the gas available to estimate the star formation efficiency (SFE). The Western tail of NGC 2782 formed isolated star clusters while massive star cluster complexes are found in the UGC 10214 (``The Tadpole'') and Eastern tail of NGC 2782. Due to the lack of both observable CO and [CII] emission, the observed star formation in the Western tail of NGC 2782 may have a low carbon abundance and represent only the first round of local star formation. While the Western tail has a normal SFE, the Eastern tail in the same galaxy has an low observed SFE. In contrast, the Tadpole tidal tail has a high observed star formation rate and a corresponding high SFE. The low SFE observed in the Eastern tail of NGC 2782 may be due to its origin as a splash region where localized gas heating is important. However, the other tails may be tidally formed regions where gravitational compression likely dominates and enhances the local star formation.
ContributorsKnierman, Karen A (Author) / Scowen, Paul (Thesis advisor) / Groppi, Christopher (Thesis advisor) / Mauskopf, Philip (Committee member) / Windhorst, Rogier (Committee member) / Jansen, Rolf (Committee member) / Arizona State University (Publisher)
Created2013
ContributorsPowell, Devon (Author) / Gardner, Carl (Thesis director) / Scannapieco, Evan (Committee member) / Windhorst, Rogier (Committee member) / Barrett, The Honors College (Contributor)
Created2012-05
Description
I present a multi-spectral analysis of the faint, uJy, radio source population in the James Webb Space Telescope North Ecliptic Pole Time Domain Field. Very Long Baseline Array pointings at the 127 brightest of ~2500 radio galaxies identified with the Very Large Array indicate active galactic nucleus contamination of approximately 9.45%. My estimates of 4.8 GHz brightness of this radio source population indicate an upper bound on this contamination of 10.6%. This is well within acceptable limits, in population studies, for the use of the radio-FIR relation in the JWST NEP TDF. This improves the utility of the field to the community by reducing the need for expensive FIR observations. I have also developed an extensive catalog of magnitudes and other data in visible bands of this population. My analysis in these bands does not give any conclusive criteria for distinguishing between AGN and SFGs. The strongest trends I do identify appear to be due to reddening by interstellar dust. Future follow-up will focus on characterizing individual sources in further depth.
ContributorsNolan, Liam (Author) / Jansen, Rolf (Thesis director) / Windhorst, Rogier (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / School of Earth and Space Exploration (Contributor) / Department of Physics (Contributor)
Created2022-05