H I observations of galaxies

II. The Coma Supercluster

¹ Universitá degli Studi di Milano-Bicocca, Piazza delle scienze 3, 20126 Milano, Italy e-mail: giuseppe.gavazzi@mib.infn.it
² NRAO, PO Box 2, Green Bank, WV 24944, USA e-mail: koneil@gb.nrao.edu
³ Laboratoire d'Astrophysique de Marseille, BP 8, Traverse du Siphon, 13376 Marseille, France e-mail: alessandro.boselli@oamp.fr
⁴ 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

Received: 18 July 2005
Accepted: 20 September 2005

Abstract

High sensitivity 21-cm H i line observations with an rms noise level of ~0.5 mJy were made of 35 spiral galaxies in the Coma Supercluster, using the refurbished Arecibo telescope, leading to detection of 25 objects. These data, combined with the measurements available in the literature, provide the set of H i data for 94% of all late-type galaxies in the Coma Supercluster with an apparent photographic magnitude  mag. We confirm that the typical scale of H i deficiency around the Coma cluster is 2 Mpc, i.e. one virial radius. Comparing the H i mass function (HIMF) of cluster with non-cluster members of the Coma Supercluster we detected a shortage of high H i mass galaxies among cluster members that can be attributed to the pattern of H i deficiency found in rich clusters.