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Astron. Astrophys. 334, 124-138 (1998)

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Spectroscopy of the circumnuclear emission line regions in Seyfert galaxies *

II. NGC 7214

Mario Radovich , Piero Rafanelli and Roberto Barbon

Department of Astronomy, University of Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italy

Received 19 March 1997 / Accepted 17 December 1997


This paper is the second of a series (Radovich and Rafanelli 1996) devoted to the investigation of the emission line properties of the circumnuclear and extranuclear regions in a sample of nearby Seyfert galaxies. Our aim is to identify star formation regions around the active nucleus and to derive their properties like star formation rate and dust content, and compare them with those observed in non-active galaxies.

We show that photoionization models may fit the observed line ratios both in the nuclear and circumnuclear regions of the Sy 1.2 galaxy NGC 7214. In the nucleus, components with different densities must be considered. In the circumnuclear regions, line ratios to projected distances of [FORMULA] 2 kpc from the nucleus are typical of ionization by a power law. At higher distances ([FORMULA] 5-8 kpc) they are fitted either by a thermal continuum or assuming that both stars and the non thermal source contribute to the ionization of the gas. A simple interpretation is suggested, in the framework of the unified model for Seyfert galaxies. Evidence for enhanced star formation, maybe related to the ongoing interaction with a close spiral galaxy, is found in only one region.

Key words: galaxies: Seyfert – galaxies: individual: NGC 7214

* Based on observations collected at ESO - La Silla (Chile)

Send offprint requests to: P. Rafanelli

© European Southern Observatory (ESO) 1998

Online publication: May 12, 1998