Volume 528, April 2011
|Number of page(s)||6|
|Published online||14 March 2011|
Kinematics and stellar population of NGC 4486A
Université de Lyon, Université Lyon 1, 69622 Villeurbanne, France ;
CRAL, Observatoire de Lyon, CNRS UMR 5574, 69561 Saint-Genis Laval France
2 Institut für Astronomie, Universität Wien, Türkenschanzstraße 17, 1180 Wien, Austria
3 Instituto de Astrofísica de Canarias, La Laguna, 38200 Tenerife ; Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain
4 Dept. of Physics & Astronomy, Ghent University, Krijgslaan 281, S9, 9000 Ghent, Belgium
Received: 17 December 2010
Accepted: 2 February 2011
Context. NGC 4486A is a low-luminosity elliptical galaxy harbouring an edge-on nuclear disk of stars and dust. It is known to host a super-massive black hole.
Aims. We study its large-scale kinematics and stellar population along the major axis to investigate the link between the nuclear and global properties.
Methods. We use long-slit medium-resolution optical spectra that we fit against stellar population models.
Results. The SSP-equivalent age is about 12 Gyr old throughout the body of the galaxy, and its metallicity decreases from [Fe/H] = 0.18 near the centre to sub-solar values in the outskirts. The metallicity gradient is −0.24 dex per decade of radius within the effective isophote. The velocity dispersion is 132 ± 3 km s-1 at 1.3″ from the centre and decreases outwards. The rotation velocity reaches a maximum km s-1 at a radius 1.3 < rmax < 2″.
Conclusions. NGC 4486A appears to be a typical low-luminosity elliptical galaxy. There is no signature in the stellar population of the possible ancient accretion/merging event that produced the disk.
Key words: galaxies: individual: NGC 4486A / galaxies: elliptical and lenticular, cD / galaxies: kinematics and dynamics / galaxies: stellar content
© ESO, 2011
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