The relationship of galaxy morphology to nuclear star formation in noninteracting spiral galaxies.

Persistent Link:
http://hdl.handle.net/10150/184893
Title:
The relationship of galaxy morphology to nuclear star formation in noninteracting spiral galaxies.
Author:
Pompea, Stephen Mark.
Issue Date:
1989
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:
Three specific questions concerning the relationship between galaxian morphology and infrared properties were addressed for non-interacting galaxies: (1) Why are high infrared luminosity (L > 10¹⁰ L(⊙)) Sa galaxies scarce compared to Sb and Sc galaxies; (2) Is there a relationship between the bulge to total luminosity and the infrared properties of early type spirals; and (3) Are bars essential to nuclear star formation processes in non-interacting galaxies? These questions were answered using IRAS data, CO (1-0) measurements, 2 μm, 10 μm, and visible CCD observations. Only 4% of Sa's in the Revised Shapley-Ames Catalog (RSAC) with B(Γ) < 12 have infrared luminosities > 10¹⁰ L(⊙), 1/6 of the ratio for Sb's and Sc's. Less than three Sa's of 166 in the RSAC have nuclear starbursts not associated with interactions or active nuclei. A comparison of neutral hydrogen fluxes and CO fluxes with infrared fluxes implies that molecular cloud formation is inhibited in Sa's, leading to the lack of infrared activity. An investigation of the role of bulges in suppressing star formation in Sa through Sb spirals relied on the photometric observations of Kent, Kodaira, and Cornell and on IRAS infrared observations. The bulge to total luminosity is uncorrelated with the ratio of infrared to blue flux, 60 μm/100 μm fluxes, or infrared luminosity. These results indicate that disk star formation is relatively unaffected by bulge size. The hypothesis that high far-infrared luminosities in non-interacting galaxies are dependent on material fed into their nuclei by bars was tested by near infrared imaging of a sample of 15 optically unbarred galaxies in a search for hidden bars. These galaxies were non-interacting, non-Seyfert galaxies with far infrared luminosities > 10¹⁰ L(⊙) and hot colors between 60 and 100 μm (S₆₀/S₁₀₀ > 0.5, indicative of nuclear starbursts). At least 8 of these galaxies do not appear to have bars. Strong bars therefore are not an absolute requirement for high infrared luminosity.
Type:
text; Dissertation-Reproduction (electronic)
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Astronomy; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Rieke, George H.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleThe relationship of galaxy morphology to nuclear star formation in noninteracting spiral galaxies.en_US
dc.creatorPompea, Stephen Mark.en_US
dc.contributor.authorPompea, Stephen Mark.en_US
dc.date.issued1989en_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.abstractThree specific questions concerning the relationship between galaxian morphology and infrared properties were addressed for non-interacting galaxies: (1) Why are high infrared luminosity (L > 10¹⁰ L(⊙)) Sa galaxies scarce compared to Sb and Sc galaxies; (2) Is there a relationship between the bulge to total luminosity and the infrared properties of early type spirals; and (3) Are bars essential to nuclear star formation processes in non-interacting galaxies? These questions were answered using IRAS data, CO (1-0) measurements, 2 μm, 10 μm, and visible CCD observations. Only 4% of Sa's in the Revised Shapley-Ames Catalog (RSAC) with B(Γ) < 12 have infrared luminosities > 10¹⁰ L(⊙), 1/6 of the ratio for Sb's and Sc's. Less than three Sa's of 166 in the RSAC have nuclear starbursts not associated with interactions or active nuclei. A comparison of neutral hydrogen fluxes and CO fluxes with infrared fluxes implies that molecular cloud formation is inhibited in Sa's, leading to the lack of infrared activity. An investigation of the role of bulges in suppressing star formation in Sa through Sb spirals relied on the photometric observations of Kent, Kodaira, and Cornell and on IRAS infrared observations. The bulge to total luminosity is uncorrelated with the ratio of infrared to blue flux, 60 μm/100 μm fluxes, or infrared luminosity. These results indicate that disk star formation is relatively unaffected by bulge size. The hypothesis that high far-infrared luminosities in non-interacting galaxies are dependent on material fed into their nuclei by bars was tested by near infrared imaging of a sample of 15 optically unbarred galaxies in a search for hidden bars. These galaxies were non-interacting, non-Seyfert galaxies with far infrared luminosities > 10¹⁰ L(⊙) and hot colors between 60 and 100 μm (S₆₀/S₁₀₀ > 0.5, indicative of nuclear starbursts). At least 8 of these galaxies do not appear to have bars. Strong bars therefore are not an absolute requirement for high infrared luminosity.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)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, George H.en_US
dc.contributor.committeememberHoffmann, William F.en_US
dc.contributor.committeememberHogan, Craig J.en_US
dc.contributor.committeememberImpey, Christopher D.en_US
dc.contributor.committeememberYoung, Erick T.en_US
dc.identifier.proquest9013154en_US
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