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dc.contributor.authorImpey, C. D.
dc.contributor.authorBothun, G. D.
dc.date.accessioned2017-06-05T18:11:21Z
dc.date.available2017-06-05T18:11:21Z
dc.date.issued1988-11
dc.identifier.citationAstrophysical Journal, Part 1 (ISSN 0004-637X), vol. 341, June 1, 1989, p. 89-104en
dc.identifier.urihttp://hdl.handle.net/10150/623912
dc.description.abstractWe present new optical and radio spectroscopic observations of the remarkable galaxy Malin 1. This galaxy has unique features that include an extremely low surface brightness disk with an enormous mass of neutral hydrogen, and a low luminosity Seyfert nucleus. Malin 1 is exceptional in its values of MHO, LB, and MHI /Ln, and modest in its surface mass density of gas and stars. Spirals with large Min /LB tend to have low mean column densities of HI, and are close to the threshold for star formation due to instabilities in a rotating gas disk. In these terms, Malin 1 has a disk with extremely inefficient star formation. The bulge spectrum is dominated by the absorption features of an old, metal rich stellar population, although there is some evidence for hot (young) stars. The emission line excitations and widths in the nucleus are typical of a Seyfert galaxy; but Malin 1 is in the lowest 5% of the luminosity function of Seyferts, despite a copious fuel supply. Malin 1 is in a low density region of the universe. We propose it as an unevolving disk galaxy, where the surface mass density is so low that the chemical composition and mass fraction in gas change very slowly over a Hubble time. Its properties are similar to those of the damped Lyman -a absorption systems seen in the spectra of high redshift quasars. We emphasize that there are strong observational selection effects against finding gas -rich galaxies that are both massive and diffuse. Finally, we suggest that large and massive HI disks may have formed as early as z - 2, and remained quiescent to the present day. Subject headings : individual (Malin 1) - galaxies : photometry - galaxies : Seyfert - galaxies : stellar content - radio sources : 21 cm radiation - stars : formation
dc.language.isoen_USen
dc.publisherSteward Observatory, The University of Arizona (Tucson, Arizona)en
dc.relation.ispartofseriesPreprints of the Steward Observatory #844en
dc.relation.urlhttp://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1989ApJ...341...89I&db_key=AST&data_type=HTML&format=&high=3ed65e9cd007589en
dc.rightsCopyright © All Rights Reserved.en
dc.sourceSteward Observatory Parker Library SO QB 4 .S752 ARCHen
dc.subjectDisk galaxiesen
dc.subjectGalaxy evolutionen
dc.subjectGalactic nucleien
dc.subjectSeyfert galaxiesen
dc.subjectStar formationen
dc.titleMALIN: A Quiescent Disk Galaxy|MALIN 1: A Quiescent Disk Galaxyen_US
dc.typetexten
dc.typeArticleen
dc.contributor.departmentUniv Arizona, Steward Observen
dc.description.collectioninformationThis title from the Steward Observatory Preprints collection is made available by the Steward Observatory Parker Library and the University Libraries, The University of Arizona. If you have questions about titles in this collection, please contact Parker Library librarian Betty Fridena, bfridena@as.arizona.edu.en
refterms.dateFOA2018-09-11T19:53:10Z
html.description.abstractWe present new optical and radio spectroscopic observations of the remarkable galaxy Malin 1. This galaxy has unique features that include an extremely low surface brightness disk with an enormous mass of neutral hydrogen, and a low luminosity Seyfert nucleus. Malin 1 is exceptional in its values of MHO, LB, and MHI /Ln, and modest in its surface mass density of gas and stars. Spirals with large Min /LB tend to have low mean column densities of HI, and are close to the threshold for star formation due to instabilities in a rotating gas disk. In these terms, Malin 1 has a disk with extremely inefficient star formation. The bulge spectrum is dominated by the absorption features of an old, metal rich stellar population, although there is some evidence for hot (young) stars. The emission line excitations and widths in the nucleus are typical of a Seyfert galaxy; but Malin 1 is in the lowest 5% of the luminosity function of Seyferts, despite a copious fuel supply. Malin 1 is in a low density region of the universe. We propose it as an unevolving disk galaxy, where the surface mass density is so low that the chemical composition and mass fraction in gas change very slowly over a Hubble time. Its properties are similar to those of the damped Lyman -a absorption systems seen in the spectra of high redshift quasars. We emphasize that there are strong observational selection effects against finding gas -rich galaxies that are both massive and diffuse. Finally, we suggest that large and massive HI disks may have formed as early as z - 2, and remained quiescent to the present day. Subject headings : individual (Malin 1) - galaxies : photometry - galaxies : Seyfert - galaxies : stellar content - radio sources : 21 cm radiation - stars : formation


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