Persistent Link:
http://hdl.handle.net/10150/184540
Title:
Infrared studies of active galaxies.
Author:
Kailey, Walter Franklin.
Issue Date:
1988
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:
IRAS observations of extragalactic objects are analyzed, supplemented by optical spectroscopy and 10 μm photometry. The relationship between various forms of activity in the nuclei of spiral galaxies and their mid- to far-infrared spectral energy distributions is explored. It is shown that more than 70% of galaxies with F₆₀/F₂₅ ≤ 3 are Seyferts, while the remainder have bright optical emission lines in their nuclear spectra. It is argued that most Seyferts are powered by their active nuclei at 25 μm, while there is some indication that Seyferts with large F₆₀/F₂₅ flux ratios are undergoing starbursts in the vicinity of their nuclei. The properties of a sample of bright, extragalactic IRAS sources are studied. A catalog containing total infrared and blue fluxes, distance estimates, recession velocities, and morphological classifications for these objects is presented. The brightest sources at mid- to far-infrared wavelengths are (in order of frequency) nearby, normal spiral galaxies; galaxies with disturbed or irregular morphology (often known as interacting galaxies); type 2 Seyferts; and dust-embedded type 1 Seyferts. All of these sources are dominated by thermal emission from dust. The dust in the peculiar, irregular, and Seyfert galaxies is exposed to a higher mean intensity of radiation. Moreover, these IR-active galaxies tend to have strong, compact nuclear sources at 11 μm, whether or not they contain a known Seyfert nucleus. The distinctive spectral behavior of IR-luminous galaxies is shown to result from the presence of compact, dust-dominated IR nuclear sources, which are the predominant cause of IR luminosities above 10¹¹ L(⊙). Compact IR sources are always associated with a dust-embedded region of ionized gas in the galaxy's nucleus, which may exhibit Seyfert, LINER, or H II region characteristics. The luminosity of the compact nuclear source is well correlated with its 60/100 μm color. This relationship is a vital clue to the nature of these sources and has potential application as a standard candle.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Active galaxies.; Infrared astronomy.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Astronomy; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Rieke, Marcia J.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleInfrared studies of active galaxies.en_US
dc.creatorKailey, Walter Franklin.en_US
dc.contributor.authorKailey, Walter Franklin.en_US
dc.date.issued1988en_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.abstractIRAS observations of extragalactic objects are analyzed, supplemented by optical spectroscopy and 10 μm photometry. The relationship between various forms of activity in the nuclei of spiral galaxies and their mid- to far-infrared spectral energy distributions is explored. It is shown that more than 70% of galaxies with F₆₀/F₂₅ ≤ 3 are Seyferts, while the remainder have bright optical emission lines in their nuclear spectra. It is argued that most Seyferts are powered by their active nuclei at 25 μm, while there is some indication that Seyferts with large F₆₀/F₂₅ flux ratios are undergoing starbursts in the vicinity of their nuclei. The properties of a sample of bright, extragalactic IRAS sources are studied. A catalog containing total infrared and blue fluxes, distance estimates, recession velocities, and morphological classifications for these objects is presented. The brightest sources at mid- to far-infrared wavelengths are (in order of frequency) nearby, normal spiral galaxies; galaxies with disturbed or irregular morphology (often known as interacting galaxies); type 2 Seyferts; and dust-embedded type 1 Seyferts. All of these sources are dominated by thermal emission from dust. The dust in the peculiar, irregular, and Seyfert galaxies is exposed to a higher mean intensity of radiation. Moreover, these IR-active galaxies tend to have strong, compact nuclear sources at 11 μm, whether or not they contain a known Seyfert nucleus. The distinctive spectral behavior of IR-luminous galaxies is shown to result from the presence of compact, dust-dominated IR nuclear sources, which are the predominant cause of IR luminosities above 10¹¹ L(⊙). Compact IR sources are always associated with a dust-embedded region of ionized gas in the galaxy's nucleus, which may exhibit Seyfert, LINER, or H II region characteristics. The luminosity of the compact nuclear source is well correlated with its 60/100 μm color. This relationship is a vital clue to the nature of these sources and has potential application as a standard candle.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectActive galaxies.en_US
dc.subjectInfrared astronomy.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineAstronomyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorRieke, Marcia J.en_US
dc.contributor.committeememberStrittmatter, Peter A.en_US
dc.contributor.committeememberTifft, William G.en_US
dc.contributor.committeememberYoung, Erick T.en_US
dc.identifier.proquest8905792en_US
dc.identifier.oclc701552834en_US
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