Astronomy & Astrophysics

Issue		A&A Volume 507, Number 2, November IV 2009
Page(s)		757 - 768
Section		Extragalactic astronomy
DOI		10.1051/0004-6361/200912546
Published online		15 September 2009

A&A 507, 757-768 (2009)
DOI: 10.1051/0004-6361/200912546

H I in nearby low-luminosity QSO host galaxies

S. König¹, A. Eckart^{1, 2}, M. García-Marín¹, and W. K. Huchtmeier²

¹ I. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937 Köln, Germany
e-mail: skoenig@ph1.uni-koeln.de
² Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany

Received 20 May 2009 / Accepted 2 September 2009

Abstract
We searched for 21 cm $\ion$ emission in a sample of 27 previously CO detected nearby galaxies hosting low-luminosity quasi - stellar objects (QSOs). In this paper we investigate the relationship between the $\ion$ and infrared properties of these host galaxies, compare the atomic and molecular gas content and look for connections to the optical and FIR properties. The single dish observations have been made with the Effelsberg 100-m telescope with a beam size of 9.5´. The sample objects have been drawn from a wide-angle survey for optically bright QSOs (HES), which have declinations $\delta >-30\degr$ and redshifts up to z = 0.06. 12 host galaxies from the sample have been detected in the $\ion$ 21 cm emission line. Eight of them have a spiral geometry, whereas the other four are bulge dominated and probably of elliptical type (E/S0). Three of the objects seem to be in a phase of merging/interaction. The neutral atomic gas masses range from $1.1 \times 10^{\rm 9}~M_{\sun}$ up to $3.8 \times 10^{\rm 10}~M_{\sun}$ . The median $\ion$ gas mass in the whole sample is of the order of $11.4 \times 10^{\rm 9}~M_{\sun}$ , which is a factor of two higher than the $\ion$ content of our galaxy. We find no strong correlation between $\ion$ mass and IR luminosity. The objects agree well within the expectations from the Tully-Fisher relation. In the color–color diagram we find all sources in the estimated locations. With the non-detected sources we clearly sample an upper envelope of this mass distribution.

Key words: galaxies: active -- radio lines: galaxies -- galaxies: nuclei -- galaxies: Seyfert

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