An H I view of the on-going assembly of early-type galaxies: Present and future observations

Abstract

We present a preliminary analysis of the H I properties of early-type galaxies in the ATLAS3D sample. Using WSRT data for ~100 galaxies outside the Virgo cluster and data from the Alfalfa project for galaxies inside Virgo, we discuss the dependence of H I properties on environment. We detect H I in about half of the galaxies outside Virgo. For these systems, the H I morphology and kinematics change as a function of environment, going from regular, rotating systems around “isolated” galaxies to progressively more disturbed structures for galaxies with neighbours or in groups. In denser environment, inside Virgo, nearly none of the galaxies contains H I. We discuss future work in this field which will be enabled by next-generation, pre-SKA radio instruments. We present a simulated Apertif H I observation of an ATLAS3D early-type galaxy, showing how its appearance and detection level vary as a function of redshift.