Astronomy and Astrophysics – Astronomy
Scientific paper
Jun 1986
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1986a%26a...161..145v&link_type=abstract
Astronomy and Astrophysics (ISSN 0004-6361), vol. 161, no. 1, June 1986, p. 145-149.
Astronomy and Astrophysics
Astronomy
19
Emission Spectra, Galactic Nuclei, Nebulae, Seyfert Galaxies, Ubv Spectra, Galactic Structure, H Alpha Line, H Ii Regions, Nonthermal Radiation, Spectral Line Width, Star Distribution, Ultraviolet Astronomy
Scientific paper
Photoelectric and spectroscopic data for the nucleus of 320 galaxies with delta less than 20 deg, galactocentic radial velocity of less than 3000 km/s, and absolute magnitude of less than -21 are studied to determine the conditions necessary for the development of Seyfert-like nebulosity and H II regions. Two classes of nuclear emission spectra are observed. One class, the H II regions ionized by hot stars, are characterized by H-alpha/forbidden N II 6583 A greater than 1.7 and FWHM less than 6 A; the second class, Seyfert-like nebulosites ionized by a nonthermal continuum, are described by H-alpha/forbidden N II 6583 A less than 1.2 and FWHM greater than 6 A. The line width for Seyfert-like nuclei is broader in early-type galaxies than in late-type spirals and for nuclear H II regions the width corresponds to the UV excess of the nucleus. The data reveal that the H II region exists in the presence of galaxies with young stars in the nucleus; however, Seyfert-like nebulosities are present in old nuclear bulges.
Véron Pascal
Veron-Cetty M.-P.
No associations
LandOfFree
Study of a complete sample of galaxies. III - Discussion and results does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Study of a complete sample of galaxies. III - Discussion and results, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Study of a complete sample of galaxies. III - Discussion and results will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1829367