We have obtained HI observations of five fields in the cluster
A 262 using
the WSRT. Eleven galaxies, ten spirals and one irregular, were detected.
The main result of our study is summarized in Fig. 11 (click here) where
we show the total
emission of the detected galaxies, located at their proper positions
in the cluster, magnified in size by a factor of six. First contours
are between 1.8 and 
, except for
NGC 668 (
) and NGC 753
(
). We did not detect any of the most
deficient galaxies in the core of the cluster.
Figure 11: Composite plot of the integrated HI maps detected
in A 262, magnified by a factor 6. Galaxies are shown at
their proper positions except when indicated by solid
lines. First contours are between 1.8 and , except for
NGC 668 and NGC 753 where contours begin at
and , respectively. The segmented 
diameter
circles outline the 5 observed fields, and numbers list the
detected galaxies in the
same order as in Table 2 (click here). The cluster center
lies at 
from NGC 710 (plotted with number 6), to
the North
Within a radius of one degree from the cluster center
(0.8 Mpc, assuming a distance to A 262 of 47 Mpc)
we found galaxies to be more extended
in HI than in the optical, except for NGC 710, located at the very
center of the cluster. This is in contrast with the results
obtained by Cayatte et al. (1990), who found galaxies in Virgo
within 3
from M 87
(0.9 Mpc, considering Virgo at a distance of 17.5 Mpc)
to be severely stripped of their neutral hydrogen.
The three galaxies in the North East field (UGC 1347, CGCG 522-049,
and UGC 1361), show HI distributions slightly offset
to the West of the optical position. These objects are close
to the X-ray source located at the center of the cluster.
Other galaxies, NGC 688 and NGC 753, show
also asymmetrical gas distributions. The cause of these
effects could be ram-pressure exerted by the intra-cluster medium.
A possible HI cloud was found near
CGCG 522-049. If real, the presence of such an object
in a cluster
would be quite surprising as it would have to survive in an extremely
hostile environment.
Further HI mapping in the
central regions of A 262, to be done with the VLA
or the upgraded WSRT, would be useful to confirm the presence
of this kind of objects as well as to explain the irregular
gas distributions observed in this work.
Acknowledgements
We have made use of the Lyon-Meudon Extragalactic Database (LEDA) supplied by the LEDA team at the CRAL-Observatoire de Lyon (France). V.C. and C.B. acknowledge financial support from the Groupement de Recherche Cosmologie. H.B.A. thanks the Consejo Nacional de Ciencia y Tecnologıa, for its support through a Ph.D. Grant. The Westerbork Synthesis Radio Telescope is operated by the Netherlands Foundation for Research in Astronomy (NFRA/ASTRON), with financial support by the Netherlands Organization for Scientific Research (N.W.O.). We thank the referee of this article, G. Gavazzi, for his helpful comments.