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Astron. Astrophys. 323, 749-761 (1997)

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Kinematics and stellar populations in active galaxies: the LINER NGC 4579 (M58)

J. Palacios 1, M.L. García-Vargas 2, Angeles Díaz 1, Roberto Terlevich 3 and Elena Terlevich 4

1 Dpto. de Física Teórica, Facultad de Ciencias, C-XI. Cantoblanco. Universidad Autónoma de Madrid, E-28049 Madrid, Spain
2 INSA; ESA IUE Observatory, Villafranca del Castillo Satellite Tracking Station, PO Box 50727, E-28080 Madrid, Spain
3 Royal Greenwich Observatory, Madingley Road, Cambridge CB30EZ, UK
4 Institute of Astronomy, Madingley Road, Cambridge CB30HA, UK

Received 10 May 1996 / Accepted 13 January 1997


We present long slit spectroscopy from the blue to the near-IR of the LINER galaxy NGC 4579 (M58). Stellar indices are used as tools to investigate if any differences in the kinematics and/or stellar content exist between the nucleus and the circumnuclear regions of the galaxy. Blue indices are found to be affected by contamination due to emission lines in the central region and the method to measure these indices is discussed. No peculiarities are found in the stellar kinematics with respect to the bulges of normal spirals, whose old population can fit the observations of the bulge of NGC 4579. Alternatively, the low central values of Mg2 and the high values of Mg1 in the blue and MgI in the near-IR lead us to propose the dominant bulge stellar population in NGC 4579 to be substantially younger than the one present in ordinary ellipticals and S0 galaxies, and therefore a population with an age of about (2.5 [FORMULA] 1) Gyr. and a metallicity of (1.5 [FORMULA] 0.5) [FORMULA] is also able to reproduce simultaneously the studied spectral indices as well as the optical spectral energy distribution of the nucleus of NGC 4579.

Key words: galaxies: NGC 4579(M58) – active – kinematics and dynamics – stellar content

Send offprint requests to: M.L. García-Vargas

© European Southern Observatory (ESO) 1997

Online publication: May 26, 1998