Early-type galaxies in different environments: an H I view

We present an analysis of deep Westerbork Synthesis Radio Telescope observations of the neutral hydrogen in 33 nearby early-type galaxies selected from a representative sample studied earlier at optical wavelengths with the SAURON integral-field spectrograph. This is the deepest homogeneous set of H I imaging data available for this class of objects. The sample covers both field environments and the Virgo cluster. Our analysis shows that gas accretion plays a role in the evolution of field early-type galaxies, but less so for those in clusters. The H I properties of SAURON early-type galaxies strongly depend on environment. For detection limits of a few times 106 M, H I is detected in about 2/3 of the field galaxies, while <10 per cent of the Virgo objects are detected. In about half of the detections, the H I forms a regularly rotating disc or ring. In many galaxies unsettled tails and clouds are seen. Al