The WSRT HALOGAS Survey

The WSRT Hydrogen Accretion in LOcal GAlaxieS (HALOGAS) survey, now being conducted with the Westerbork Synthesis Radio Telescope (WSRT), aims at performing the first systematic investigation of cold gas accretion in nearby spiral galaxies. In the scope of this new WSRT survey, we will observe neutral hydrogen gas in 22 nearby spiral galaxies with a wide spread in morphological type, with an integration time of 120 hours per target. This is sufficient to detect faint, neutral gas in the outskirts of the target galaxies. The telescope design enables us to achieve a significantly better picture of the diffuse HI structure and its kinematics in the outskirts of the observed galaxies than has been achieved in most other HI surveys of nearby spiral galaxies. The detected amount of anomalous gas, indicative of either gas accretion or a fountain mechanism, varies significantly from galaxy to galaxy.