NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
The stellar content of the nuclear regions of Sc galaxiesStellar-population syntheses based on absolute spectral energy distributions over the wavelength range from 3300 to 10,400 A are used to determine the stellar content of the nuclear regions of seven nearby Sc galaxies (NGC 628, 1073, 1084, 1637, 2903, 4321, and 5194). A linear-programming procedure is employed to construct models of the overall stellar populations whose spectra closely match those of the seven galaxies. Absolute measurements of the emission-line spectra of the nuclear regions are also provided. It is found that: (1) intrinsic reddening is probably present in each nuclear region; (2) the upper main sequence is substantially populated in most of the models; (3) the lower main sequence contributes insignificantly to the luminosity in all optimal solutions; (4) substantial contributions are made by evolved M stars at long wavelengths in all the models; (5) the model photometric M/L ratios are low, of the order of unity; and (6) the O-B stars arising naturally in the population models are just sufficient to provide the observed nuclear ionization in all the galaxies except NGC 5194, which may be collisionally ionized. The properties of the nuclear regions are shown to be consistent with the existence of a common initial mass function for star formation and a variety of time dependences for the star-formation process. A possibly significant correlation is noted between nuclear stellar content and overall dynamical properties in four of the galaxies.
Document ID
19770032728
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Turnrose, B. E.
(NASA Johnson Space Center Houston, Tex.; Hale Observatories, Pasadena, Calif., United States)
Date Acquired
August 9, 2013
Publication Date
November 15, 1976
Publication Information
Publication: Astrophysical Journal
Volume: 210
Subject Category
Astrophysics
Accession Number
77A15580
Funding Number(s)
CONTRACT_GRANT: NSF MPS-74-23453
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available