Persistent Link:
http://hdl.handle.net/10150/288790
Title:
Stellar populations in merging galaxies
Author:
Turner, Anne Marie, 1969-
Issue Date:
1998
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.
Abstract:
To examine the stellar populations of interacting or merging galaxies, a sample of 28 objects with disturbed morphology was selected. Integrated spectra of these galaxies were obtained, to study their global star formation histories and provide a database for comparison with morphologically disturbed galaxies at high redshift. Quantitative star formation histories were determined using evolutionary population synthesis models. Special emphasis was placed on observational and systematic uncertainties, e.g., IMF, metallicity, and reddening. The merger sample was divided into two subsamples for comparison with morphologically normal galaxies. The red subsample consists of galaxies whose spectra resemble those of early-type galaxies, while the blue subsample has moderate to strong Halpha emission. The model fits to the spectra of the red merger sample are indistinguishable from those in a control sample of S0 galaxies. Differences in the upper limits on recent star formation between these mergers and a sample of elliptical galaxies may be due to metallicity effects. The minimum amount of star formation required in the last Gyr is consistent with zero for the red merger and the E/S0 samples. The maximum amount of new star formation ranges from 0.2-3.2% by mass in the merger sample and 0.0-2.7% in the E/S0 control sample. Reddening contributes the largest source of uncertainty in determining the mass of a starburst in the blue merger subsample, while burst ages are relatively unaffected. We put limits on the quantitative star formations histories in these galaxies, although the uncertainties tend to be large. We find starbursts ranging in age from 10⁷ to 10⁹ years, and burst masses from 0 to more than 20% of the total stellar mass. We find higher recent rates of star formation in the merger sample based on far-infrared luminosities and Balmer absorption strengths, respectively. We cannot distinguish between truncated star formation followed by a starburst, and alternate star formation histories, such as those appropriate to spiral-type star formation, based on our model fits alone. A Salpeter IMF appears to be an adequate one to describe star formation in these galaxies.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Physics, Astronomy and Astrophysics.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Astronomy
Degree Grantor:
University of Arizona
Advisor:
Kennicutt, Robert C., Jr.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleStellar populations in merging galaxiesen_US
dc.creatorTurner, Anne Marie, 1969-en_US
dc.contributor.authorTurner, Anne Marie, 1969-en_US
dc.date.issued1998en_US
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.abstractTo examine the stellar populations of interacting or merging galaxies, a sample of 28 objects with disturbed morphology was selected. Integrated spectra of these galaxies were obtained, to study their global star formation histories and provide a database for comparison with morphologically disturbed galaxies at high redshift. Quantitative star formation histories were determined using evolutionary population synthesis models. Special emphasis was placed on observational and systematic uncertainties, e.g., IMF, metallicity, and reddening. The merger sample was divided into two subsamples for comparison with morphologically normal galaxies. The red subsample consists of galaxies whose spectra resemble those of early-type galaxies, while the blue subsample has moderate to strong Halpha emission. The model fits to the spectra of the red merger sample are indistinguishable from those in a control sample of S0 galaxies. Differences in the upper limits on recent star formation between these mergers and a sample of elliptical galaxies may be due to metallicity effects. The minimum amount of star formation required in the last Gyr is consistent with zero for the red merger and the E/S0 samples. The maximum amount of new star formation ranges from 0.2-3.2% by mass in the merger sample and 0.0-2.7% in the E/S0 control sample. Reddening contributes the largest source of uncertainty in determining the mass of a starburst in the blue merger subsample, while burst ages are relatively unaffected. We put limits on the quantitative star formations histories in these galaxies, although the uncertainties tend to be large. We find starbursts ranging in age from 10⁷ to 10⁹ years, and burst masses from 0 to more than 20% of the total stellar mass. We find higher recent rates of star formation in the merger sample based on far-infrared luminosities and Balmer absorption strengths, respectively. We cannot distinguish between truncated star formation followed by a starburst, and alternate star formation histories, such as those appropriate to spiral-type star formation, based on our model fits alone. A Salpeter IMF appears to be an adequate one to describe star formation in these galaxies.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectPhysics, Astronomy and Astrophysics.en_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.identifier.proquest9829335en_US
dc.identifier.bibrecord.b38552292en_US
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