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Nuclear activity and stellar population of a sample of interacting galaxies *
M.G. Pastoriza 1,3,
C.J. Donzelli 2,3 and
C. Bonatto 1
Received 11 September 1998 / Accepted 19 March 1999
In this paper we investigate the nuclear activity and stellar population in a sample of 27 physical galaxy pairs. Equivalent widths of absorption features are used to characterise the nuclear stellar population according to templates: most galaxies of the sample have important flux contributions from stars younger than years. According to classical diagnostic-diagrams the galaxies in our sample are either classified as H II regions or have emission line ratios near the transition zone between H II regions and LINERs. Based on the observed spectra, only 4 galaxies show LINER properties and 1 nucleus is a Seyfert 2. We found that the spectrum of a transition object (38% of the sample) can be described by a combination of an AGN with an H II region. As a result, 20 galaxies of the present sample may host a low-luminosity active nucleus.
Key words: galaxies: active galaxies: interactions galaxies: nuclei galaxies: stellar content
* Based on observations made at CASLEO and CTIO. Complejo Astronómico El Leoncito (CASLEO) is operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba and San Juan.
Send offprint requests to: M.G. Pastoriza
Online publication: June 18, 1999