EDP Sciences
Free access
Volume 437, Number 1, July I 2005
Page(s) L19 - L22
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:200500127

A&A 437, L19-L22 (2005)
DOI: 10.1051/0004-6361:200500127


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

T. Oosterloo1 and J. van Gorkom2, 3

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)

We report the discovery of a large $\ion{H}{i}$ cloud in the central regions of the Virgo cluster. It is $110\times 25$ kpc in size and contains $3.4\times 10^8~M_\odot$ of  $\ion{H}{i}$. The morphology and kinematics of this cloud strongly suggest that it consists of $\ion{H}{i}$ 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 $\ion{H}{ii}$ regions known to exist in Virgo may have formed from gas stripped from cluster galaxies. The existence of the $\ion{H}{i}$ plume suggests that stripping of infalling spirals contributes to the enrichment of the ICM. The $\ion{H}{i}$ 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".

Key words: intergalactic medium -- galaxies: interaction -- galaxies: clusters: individual: Virgo cluster -- galaxies: individual: NGC 4388

SIMBAD Objects in preparation

© ESO 2005