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Long-slit optical spectroscopy of powerful far-infrared galaxies - The nature of the nuclear energy sourceOptical spectroscopic data are presented for a sample of 47 powerful far-IR galaxies chosen for IR spectral shape, and for six other IR-bright galaxies. The stellar absorption lines expected from a population of old stars are generally very weak in the nuclei of the galaxies. Very weak Mg I absorption is found in regions well off the nucleus, implying that the visible spectrum is dominated by young stars and not by an AGN. At least one, and probably five, of the galaxies have detectable WR emission features, providing additional evidence for a young stellar population. About 20 percent of the galaxies have strong Balmer absorption lines, indicating the presence of a substantial intermediate-age stellar population. The equivalent width of the H-alpha emission line can be modeled as arising from a mixture of a large young population and an intermediate-age population of stars.
Document ID
19900032444
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Armus, Lee (Maryland, University College Park, United States)
Heckman, Timothy M. (Johns Hopkins University Baltimore, MD, United States)
Miley, George K. (Leiden Rijksuniversiteit, Sterrewacht, Netherlands)
Date Acquired
August 14, 2013
Publication Date
December 15, 1989
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 347
ISSN: 0004-637X
Subject Category
ASTROPHYSICS
Funding Number(s)
CONTRACT_GRANT: NSF AST-85-15896
Distribution Limits
Public
Copyright
Other