Infrared Insights on the Nature and Evolution of Star-Forming Galaxies

Persistent Link:
http://hdl.handle.net/10150/242433
Title:
Infrared Insights on the Nature and Evolution of Star-Forming Galaxies
Author:
Rujopakarn, Wiphu
Issue Date:
2012
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:
The peak of the star formation rate (SFR) of the Universe is widely accepted to be at 1 < z < 3, after which the SFR declined by more than an order of magnitude to the present level. The mechanisms resulting in the decline and the nature of individual star-forming galaxies at the peak of galaxy evolution, however, are poorly understood. This thesis summarizes an effort to understand both the statistical properties of star-forming galaxies and the physical conditions in individual galaxies at 0 < z < 3. I have studied the star formation (SF) sizes of local and high-z ultraluminous infrared galaxies (ULIRGs) using Pa-alpha, 24 micron and radio continuum observations and discovered that high-z ULIRGs have extended SF regions over 3-10 kpc, similar to local lower LIR SF galaxies, but with a scaled-up star formation rate surface density, ∑(SFR). Local ULIRGs, in contrast, are compact and invariably merger-triggered starbursts. A major implication to galaxy evolution is that there is a route besides major mergers to trigger very high levels of SF activity at z ~ 2, a conclusion further supported by our morphological study. I also find star formation rate surface density to be a good indicator of the IR galaxy spectral energy distribution universally and use this fact to develop a new SFR estimator using single-band 24 micron observations. The resulting indicator predicts IR luminosity and SFR within 0.15 dex of the values measured with far-IR photometry. This affords the deepest unobscured probe of SF at 0 < z < 3. According to my separate study, the spread of extinction values of SF galaxies is larger than previously known from optical observations and also indicates a large variety of dust distribution scenarios, from a uniform mixture that resembles the extinction screen assumption to inhomogeneous mixtures, which could undermine the assumptions commonly used to correct for extinction at high-z and necessitates the use of unobscured SF tracers. Lastly, I present the luminosity functions of galaxies and their evolution measured from IR observations out to z = 1.2.
Type:
text; Electronic Dissertation
Keywords:
Astronomy
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Astronomy
Degree Grantor:
University of Arizona
Advisor:
Rieke, George

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleInfrared Insights on the Nature and Evolution of Star-Forming Galaxiesen_US
dc.creatorRujopakarn, Wiphuen_US
dc.contributor.authorRujopakarn, Wiphuen_US
dc.date.issued2012-
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.abstractThe peak of the star formation rate (SFR) of the Universe is widely accepted to be at 1 < z < 3, after which the SFR declined by more than an order of magnitude to the present level. The mechanisms resulting in the decline and the nature of individual star-forming galaxies at the peak of galaxy evolution, however, are poorly understood. This thesis summarizes an effort to understand both the statistical properties of star-forming galaxies and the physical conditions in individual galaxies at 0 < z < 3. I have studied the star formation (SF) sizes of local and high-z ultraluminous infrared galaxies (ULIRGs) using Pa-alpha, 24 micron and radio continuum observations and discovered that high-z ULIRGs have extended SF regions over 3-10 kpc, similar to local lower LIR SF galaxies, but with a scaled-up star formation rate surface density, ∑(SFR). Local ULIRGs, in contrast, are compact and invariably merger-triggered starbursts. A major implication to galaxy evolution is that there is a route besides major mergers to trigger very high levels of SF activity at z ~ 2, a conclusion further supported by our morphological study. I also find star formation rate surface density to be a good indicator of the IR galaxy spectral energy distribution universally and use this fact to develop a new SFR estimator using single-band 24 micron observations. The resulting indicator predicts IR luminosity and SFR within 0.15 dex of the values measured with far-IR photometry. This affords the deepest unobscured probe of SF at 0 < z < 3. According to my separate study, the spread of extinction values of SF galaxies is larger than previously known from optical observations and also indicates a large variety of dust distribution scenarios, from a uniform mixture that resembles the extinction screen assumption to inhomogeneous mixtures, which could undermine the assumptions commonly used to correct for extinction at high-z and necessitates the use of unobscured SF tracers. Lastly, I present the luminosity functions of galaxies and their evolution measured from IR observations out to z = 1.2.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectAstronomyen_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.advisorRieke, Georgeen_US
dc.contributor.committeememberEisenstein, Daniel J.en_US
dc.contributor.committeememberJannuzi, Buell T.en_US
dc.contributor.committeememberDavé, Romeelen_US
dc.contributor.committeememberRobertson, Brant E.en_US
dc.contributor.committeememberRieke, Georgeen_US
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