HI observations of galaxies in the southern filament of the Virgo Cluster with the Square Kilometre Array Pathfinder KAT-7 and the Westerbork Synthesis Radio Telescope

We map the H I distribution of galaxies in a similar to 1.5 x 2.5 degrees region located at the virial radius south of the Virgo Cluster using the KAT-7 and the Westerbork Synthesis Radio Telescope interferometers. Because of the different beam sizes of the two telescopes, a similar column density sensitivity of N-HI similar to 1 x 10(18) atoms cm(-2) was reached with the two observations over 16.5 km s(-1). We pioneer a new approach to combine the observations and take advantage of their sensitivity to both the large-and small-scale structures. Out to an unprecedented extent, we detect an HI tail of similar to 60 kpc being stripped off NGC 4424, a peculiar spiral galaxy. The properties of the galaxy, together with the shape of the tail, suggest that NGC 4424 is a post-merger galaxy undergoing ram pressure stripping as it falls towards the centre of the Virgo Cluster. We detect a total of 14 galaxies and three HI clouds lacking optical counterparts. One of the clouds is a new detection with an HI mass of 7 x 10(7)M(circle dot) and a strong HI profile with W-50 = 73 km s(-1). We find that 10 out of the 14 galaxies present HI deficiencies not higher than those of the cluster's late spirals, suggesting that the environmental effects are not more pronounced in the region than elsewhere in the cluster.