SAURON: Integral-field Spectroscopy of Galaxies

Abstract

We present the first results from a new and unique integral-field spectrograph, SAURON. Based upon the TIGER concept, SAURON uses a lens array to obtain two-dimensional spectroscopy with complete spatial coverage over a field of 33"x41" in low-resolution mode (0.94" lenslets) and of 9"x11" in high-resolution mode (0.26" lenslets). The spectra cover the wavelengths from 4800A to 5400A with a spectral resolution of ~3A (sigma~75 km/s. SAURON achieved first light during commissioning on the William Herschel Telescope on 1 February 1999. We are now commencing a systematic survey of the velocity dispersions, velocity fields, and line-strength distributions of nearby ellipticals and spiral bulges. The wide field of SAURON will be crucial for unraveling complicated velocity structures. In combination with available long-slit spectroscopy of the outer regions of the galaxies, HST spectra of the nuclei, HST imaging, and dynamical modeling, we will constrain the intrinsic shapes, mass-to-light ratios, and stellar populations in spheroids.