Completing H I observations of galaxies in the Virgo cluster^*

¹ Universitá degli Studi di Milano-Bicocca, Piazza delle scienze 3, 20126 Milano, Italy e-mail: giuseppe.gavazzi@mib.infn.it
² Laboratoire d'Astrophysique de Marseille, BP8, Traverse du Siphon, 13376 Marseille, France e-mail: alessandro.boselli@oamp.fr
³ Observatoire de Paris, Section de Meudon, GEPI, CNRS UMR 8111 and Université Paris 7, 5 place Jules Janssen, 92195 Meudon Cedex, France e-mail: wim.vandriel@obspm.fr
⁴ NRAO, PO Box 2, Green Bank, WV 24944, USA e-mail: koneil@gb.nrao.edu

Received: 16 July 2004
Accepted: 2 September 2004

Abstract

High sensitivity (rms noise ∼0.5 mJy) 21-cm H i line observations were made of 33 galaxies in the Virgo cluster, using the refurbished Arecibo telescope, which resulted in the detection of 12 objects. These data, combined with the measurements available from the literature, provide the first set of H i data that is complete for all 355 late-type (Sa-Im-BCD) galaxies in the Virgo cluster with  mag. The Virgo cluster H i mass function (HIMF) that was derived for this optically selected galaxy sample is in agreement with the HIMF derived for the Virgo cluster from the blind HIJASS H i survey and is inconsistent with the Field HIMF. This indicates that both in this rich cluster and in the general field, neutral hydrogen is primarily associated with late-type galaxies, with marginal contributions from early-type galaxies and isolated H i clouds. The inconsistency between the cluster and the field HIMF derives primarily from the difference in the optical luminosity function of late-type galaxies in the two environments, combined with the HI deficiency that is known to occur in galaxies in rich clusters.