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Star formation in blue galaxies. I - Ultraviolet, optical, and infrared observations of NGC 4214 and NGC 4670NGC 4214 and NGC 4760 have been observed between 1150 A and 1950 A with the IUE satellite, and new infrared and optical broad-band photometry have been obtained. The spectra of both galaxies are dominated by O stars, and, in the spectrum of NGC 4214, the C IV 1550 A line exhibits a P Cygni profile indicative of hot stars with large mass-loss rates. Although the optical spectra of both galaxies are dominated by strong narrow emission lines, no strong emission lines are seen in the UV (the observed Ly-alpha flux is dominated by geocoronal emission). Both galaxies contain giant H II region complexes in which the energy (in particular, the H-beta luminosity and the ultraviolet continuum) is provided by several hundred O stars. The comparison of the observed UVOIR energy distributions with evolutionary population models indicates that the regions observed consist of young 'bursts' of star formation superposed on an underlying old population. The initial mass function for this epoch of star formation is constrained to be similar in slope to or flatter than the Salpeter function.
Document ID
19840031852
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Geller, M. J.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Hartmann, L.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Fabbiano, G.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Huchra, J. P.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Gallagher, J.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Hunter, D.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Aaronson, M.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Date Acquired
August 12, 2013
Publication Date
November 1, 1983
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 274
ISSN: 0004-637X
Subject Category
Astronomy
Accession Number
84A14639
Funding Number(s)
CONTRACT_GRANT: NSF AST-81-17365
CONTRACT_GRANT: NAG5-87
Distribution Limits
Public
Copyright
Other

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