The Westerbork HI survey of spiral and irregular galaxies

Free access article

Issue		A&A Volume 442, Number 1, October IV 2005


Page(s)		137 - 157
Section		Extragalactic astronomy
DOI		http://dx.doi.org/10.1051/0004-6361:20053172

A&A 442, 137-157 (2005)
DOI: 10.1051/0004-6361:20053172

III. HI observations of early-type disk galaxies

E. Noordermeer¹, J. M. van der Hulst¹, R. Sancisi^{1, 2}, R. A. Swaters³ and T. S. van Albada¹

¹ Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands
e-mail: edo@astro.rug.nl
² INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
³ Department of Astronomy, University of Maryland, College Park, MD 20742-2421, USA

(Received 1 April 2005 / Accepted 29 June 2005 )

Abstract
We present HI observations of 68 early-type disk galaxies from the WHISP survey. They have morphological types between S0 and Sab and absolute B-band magnitudes between -14 and -22. These galaxies form the massive, high surface-brightness extreme of the disk galaxy population, few of which have been imaged in HI before. The HI properties of the galaxies in our sample span a large range; the average values of ${M}_{H{\sc i}}/{L}_B$ and ${D}_{H{\sc i}}/{D}_{25}$ are comparable to the ones found in later-type spirals, but the dispersions around the mean are larger. No significant differences are found between the S0/S0a and the Sa/Sab galaxies. Our early-type disk galaxies follow the same HI mass-diameter relation as later-type spiral galaxies, but their effective HI surface densities are slightly lower than those found in later-type systems. In some galaxies, distinct rings of HI emission coincide with regions of enhanced star formation, even though the average gas densities are far below the threshold of star formation derived by Kennicutt (1989, ApJ, 344, 685). Apparently, additional mechanisms, as yet unknown, regulate star formation at low surface densities. Many of the galaxies in our sample have lopsided gas morphologies; in most cases this can be linked to recent or ongoing interactions or merger events. Asymmetries are rare in quiescent galaxies. Kinematic lopsidedness is rare, both in interacting and isolated systems. In the appendix, we present an atlas of the HI observations: for all galaxies we show HI surface density maps, global profiles, velocity fields and radial surface density profiles.

Key words: surveys -- galaxies: fundamental parameters -- galaxies: ISM -- galaxies: kinematics and dynamics -- galaxies: spiral

SIMBAD Objects
Tables at the CDS

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.