Persistent Link:
http://hdl.handle.net/10150/305142
Title:
Spectral Diagnostics of Galaxy Evolution
Author:
Moustakas, John
Issue Date:
2006
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Embargo:
Dissertation Not Available (per Author's Request); UA Affiliates can find item in ProQuest Dissertations database
Abstract:
Despite considerable progress in recent years, a complete description of the physical drivers of galaxy formation and evolution remains elusive, in part because of our poor understanding of star formation, and how star formation in galaxies is regulated by feedback from supernovae and massive stellar winds. Insight into the star formation histories of galaxies, and the interplay between star formation and feedback, can be gained by measuring their chemical abundances, which until recently has only been possible for galaxies in the nearby universe. However, reliable star formation and abundance calibrations have been hampered by various systematic uncertainties, and the lack of a suitable spectrophotometric sample with which to develop better calibrations. To address the limitations of existing surveys, we have obtained integrated optical spectra for a diverse sample of more than four hundred nearby star-forming galaxies. Using these data, in conjunction with observations from the Sloan Digital Sky Survey, we conduct a detailed analysis of optical star formation indicators, and develop empirical calibrations for the [O II] 3727 and H-beta 4861 nebular emission lines. Next, we investigate whether integrated spectroscopy of star forming galaxies can be used to infer their gas-phase oxygen abundances in the presence of radial abundance gradients, diffuse-ionized gas emission, and dust attenuation. We conclude that the integrated R23 parameter is generally insensitive to these systematic effects, enabling the gas-phase metallicity to be measured with a precision of +/-0.1 dex. We apply these methods to study the evolution in the luminosity-metallicity relation at 0<z<1 based on an analysis of more than 3500 I-band selected galaxies observed as part of the AGN and Galaxy Evolution Survey, and data culled from the literature. Our principal results are that, at fixed luminosity, the mean gas-phase metallicity of luminous (MB<-19 mag), star-forming galaxies at z=1 is a factor of two lower than the gas-phase metallicity in comparably luminous galaxies at z=0. However, after accounting for the effects of luminosity evolution, we find that the amount of chemical evolution for luminous galaxies corresponds to an increase of only 10%-20% since z1⁺ё, assuming a direct evolutionary connection between nearby and distant star-forming galaxies.
Type:
text; Electronic Dissertation
Keywords:
Astronomy; Galaxies -- Evolution; Stars -- Formation
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Astronomy
Degree Grantor:
University of Arizona
Advisor:
Kennicutt, Robert C., Jr.; Zaritsky, Dennis

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleSpectral Diagnostics of Galaxy Evolutionen_US
dc.creatorMoustakas, Johnen_US
dc.contributor.authorMoustakas, Johnen_US
dc.date.issued2006-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.releaseDissertation Not Available (per Author's Request); UA Affiliates can find item in ProQuest Dissertations databaseen_US
dc.description.abstractDespite considerable progress in recent years, a complete description of the physical drivers of galaxy formation and evolution remains elusive, in part because of our poor understanding of star formation, and how star formation in galaxies is regulated by feedback from supernovae and massive stellar winds. Insight into the star formation histories of galaxies, and the interplay between star formation and feedback, can be gained by measuring their chemical abundances, which until recently has only been possible for galaxies in the nearby universe. However, reliable star formation and abundance calibrations have been hampered by various systematic uncertainties, and the lack of a suitable spectrophotometric sample with which to develop better calibrations. To address the limitations of existing surveys, we have obtained integrated optical spectra for a diverse sample of more than four hundred nearby star-forming galaxies. Using these data, in conjunction with observations from the Sloan Digital Sky Survey, we conduct a detailed analysis of optical star formation indicators, and develop empirical calibrations for the [O II] 3727 and H-beta 4861 nebular emission lines. Next, we investigate whether integrated spectroscopy of star forming galaxies can be used to infer their gas-phase oxygen abundances in the presence of radial abundance gradients, diffuse-ionized gas emission, and dust attenuation. We conclude that the integrated R23 parameter is generally insensitive to these systematic effects, enabling the gas-phase metallicity to be measured with a precision of +/-0.1 dex. We apply these methods to study the evolution in the luminosity-metallicity relation at 0<z<1 based on an analysis of more than 3500 I-band selected galaxies observed as part of the AGN and Galaxy Evolution Survey, and data culled from the literature. Our principal results are that, at fixed luminosity, the mean gas-phase metallicity of luminous (MB<-19 mag), star-forming galaxies at z=1 is a factor of two lower than the gas-phase metallicity in comparably luminous galaxies at z=0. However, after accounting for the effects of luminosity evolution, we find that the amount of chemical evolution for luminous galaxies corresponds to an increase of only 10%-20% since z1⁺ё, assuming a direct evolutionary connection between nearby and distant star-forming galaxies.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectAstronomyen_US
dc.subjectGalaxies -- Evolutionen_US
dc.subjectStars -- Formationen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineAstronomyen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorKennicutt, Robert C., Jr.en_US
dc.contributor.advisorZaritsky, Dennisen_US
dc.contributor.committeememberKennicutt, Robert C., Jr.en_US
dc.contributor.committeememberZaritsky, Dennisen_US
dc.contributor.committeememberArnett, Daviden_US
dc.contributor.committeememberDavé, Romeelen_US
dc.contributor.committeememberSkillman, Evan D.en_US
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