EDP Sciences
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Volume 394, Number 3, November II 2002
Page(s) 863 - 872
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20021246

A&A 394, 863-872 (2002)
DOI: 10.1051/0004-6361:20021246

On-axis spatially resolved spectroscopy of low redshift quasar host galaxies: HE 1503+0228, at z=0.135

F. Courbin1, 2, G. Letawe1, P. Magain1, L. Wisotzki3, P. Jablonka4, K. Jahnke5, B. Kuhlbrodt5, D. Alloin6, G. Meylan7, D. Minniti2 and I. Burud7

1  Institut d'Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août, 17 Sart Tilman (Bat. B5C), Liège 1, Belgium
2  Universidad Católica de Chile, Departamento de Astronomia y Astrofisica, Casilla 306, Santiago 22, Chile
3  Institut für Physik, Universität Potsdam, Am Neuen Palais 10, 14469 Potsdam, Germany
4  GEPI, Observatoire de Paris, Place Jules Janssen, 92915 Meudon Cedex, France
5  Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
6  European Southern Observatory, Casilla 19, Santiago, Chile
7  Space Telescope Science institute, 3700 San Martin Drive, Baltimore, MD 21218, USA

(Received 14 May 2002 / Accepted 23 August 2002)

We present the first result of a comprehensive spectroscopic study of quasar host galaxies. On-axis, spatially resolved spectra of low redshift quasars have been obtained with FORS1, mounted on the 8.2 m ESO Very Large Telescope, Antu. The spectra are spatially deconvolved using a spectroscopic version of the "MCS deconvolution algorithm". The algorithm decomposes two dimensional spectra into the individual spectra of the central point-like nucleus and of its host galaxy. Applied to HE 1503+0228 at z=0.135 ( MB=-23.0), it provides us with the spectrum of the host galaxy between 3600 Å and 8500 Å (rest-frame), at a mean resolving power of 700. The data allow us to measure several of the important Lick indices. The stellar populations and gas ionization state of the host galaxy of HE 1503+0228 are very similar to the ones measured for normal non-AGN galaxies. Dynamical information is also available for the gas and stellar components of the galaxy. Using deconvolution and a deprojection algorithm, velocity curves are derived for emission lines, from the center up to 4´´ away from the nucleus of the galaxy. Fitting a simple three-components mass model (point mass, spherical halo of dark matter, disk) to the position-velocity diagram, we infer a mass of $M(r<1~{\rm kpc}) = (2.0 \pm 0.3)\times
10^{10}~M_{\odot}$ within the central kiloparsec of the galaxy, and a mass integrated over 10 kpc of $M(r<10~{\rm kpc}) = (1.9 \pm 0.3) \times 10^{11}~
M_{\odot}$ , with an additional 10% error due to the uncertainty on the inclination of the galaxy. This, in combination with the analysis of the stellar populations indicates that the host galaxy of HE 1503+0228 is a normal spiral galaxy.

Key words: galaxies: kinematics and dynamics -- galaxies: stellar content -- quasars: individual: HE 1503+0228 -- techniques: image processing

Offprint request: G. Letawe, Frederic.Courbin@ulg.ac.be

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© ESO 2002