Ionized Gas in Spheroids: The SAURON Survey

Abstract. Early results are reported from the SAURON survey of thekinematics and stellar populations of nearby cluster and field E, S0, andSa galaxies. We present maps of the Hβ and [OIII] emission-line distri-bution and kinematics for NGC 5813 and NGC 7742.1. IntroductionStudies with HST have revealed a variety of structures in the nuclei of nearbyelliptical galaxies: stellar and/or gaseous disks, massive central black holes, unre-solved nuclear spikes, and kinematically decoupled structures. Progress towardsa better understanding of the properties of nearby galaxies requires a system-atic investigation of the large-scale (ground-based) kinematics and line-strengthsof a representative sample. Traditionally such studies relied on long-slit spec-troscopy along at most a few position angles, but this is insufficient to unravelthe rich internal kinematics of spheroids. For this reason we built the panoramicintegral-field spectrograph SAURON for the William Herschel Telescope.The design of SAURON is similar to that of the prototype integral-fieldspectrograph TIGER and its successor OASIS built for the CFHT (Bacon etal. 1995, 2000). The field of view is 33