Letter to the Editor

A large H I cloud near the centre of the Virgo cluster

¹ Netherlands Foundation for Research in Astronomy, Postbus 2, 7990 AA, Dwingeloo, The Netherlands e-mail: oosterloo@astron.nl
² Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027, USA
³ Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 AV Groningen, The Netherlands

Received: 22 April 2005
Accepted: 18 May 2005

Abstract

We report the discovery of a large  cloud in the central regions of the Virgo cluster. It is  kpc in size and contains of . The morphology and kinematics of this cloud strongly suggest that it consists of  removed from the galaxy NGC 4388 by ram-pressure stripping. It is more likely the result of an interaction of the ISM of NGC 4388 with the hot halo of the M 86 group and not with the ICM centred on M 87. The large extent of the plume suggests that gas stripped from cluster galaxies can remain neutral for at least 10⁸ yr. Locally, the column density is well above 10²⁰ cm^-2, suggesting that the intra-cluster  regions known to exist in Virgo may have formed from gas stripped from cluster galaxies. The existence of the  plume suggests that stripping of infalling spirals contributes to the enrichment of the ICM. The  object in the Virgo cluster recently reported by Minchin et al. (2005, ApJ, 622, L21) may have a similar origin and may therefore not be a “dark galaxy”.