The Properties of "Dwarf" Seyfert Nuclei in Nearby Galaxies
Abstract
Accurate knowledge of the luminosity function of active galactic nuclei over a wide range of absolute magnitudes is a prerequisite to understanding their structure and evolution. Here we describe preliminary results from a large survey of bright, nearby galaxies which is designed to quantify the faint end of the luminosity function. Many high-quality spectra are shown to emphasize the great variety of physical conditions in the nuclei and to illustrate the methods used in a detailed analysis of the data. The characteristics of Seyfert galaxies are detected in a surprisingly large number of objects, although at much fainter levels than usually reported for classical AGNs. In particular, broad Hα emission is visible in at least 10% of the nuclei, and the relative intensities of narrow lines are often indicative of photoionization by a nonstellar continuum. A very wide range of densities is found in the narrow-line regions of certain low-ionization nuclei, just as in many QSOs and Seyfert 1 galaxies. These results suggest that intrinsically faint ("dwarf"), but nevertheless active, nuclei are much more common than previously believed, and that they may have evolved from luminous quasars.
Additional Information
© Springer Science+Business Media Dordrecht 1986. Research based on observations made at Palomar Observatory, Caltech. We thank the Time Allocation Committee of Palomar Observatory for providing a generous number of nights on the Hale reflector. Many technicians and telescope operators were of great help during the acquisition of data. John Biretta provided one of the main computer programs used in the subsequent analysis. Figures 1, 6, 8, 10, 13, 14, 15, and 16 have previously been published (FH; Filippenko 1985; Paper I), and are reproduced here courtesy of The Astrophysical Journal. This research was supported by NSF grant AST 82-16544 to W. L. W. S., as well as by fellowships to A. V. F. from the Fannie and John Hertz Foundation and from the Miller Institute for Basic Research in Science (U.C. Berkeley). A. V. F. is also grateful to the organizing committee of this conference for financial assistance.Additional details
- Eprint ID
- 105674
- Resolver ID
- CaltechAUTHORS:20200930-113054293
- AST 82-16544
- NSF
- Fannie and John Hertz Foundation
- Miller Institute for Basic Research in Science
- Created
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2020-10-01Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Series Name
- Astrophysics and Space Science Library
- Series Volume or Issue Number
- 121