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The SAURON project – VIII. OASIS/CFHT integral-field spectroscopy of elliptical and lenticular galaxy centres*

2006; Oxford University Press; Volume: 373; Issue: 3 Linguagem: Inglês

10.1111/j.1365-2966.2006.11065.x

1365-2966

Richard M. McDermid, Éric Emsellem, Kristen L. Shapiro, Roland Bacon, Martin Bureau, Michele Cappellari, Roger L. Davies, P. T. de Zeeuw, J. Falcón‐Barroso, Davor Krajnović, H. Kuntschner, R. F. Peletier, M. Sarzi,

Plant Water Relations and Carbon Dynamics

We present high spatial resolution integral-field spectroscopy of 28 elliptical (E) and lenticular (S0) galaxies from the SAURON representative survey obtained with the OASIS spectrograph during its operation at the CFHT. These seeing-limited observations explore the central 8"x10" (typically one kiloparsec diameter) regions of these galaxies using a spatial sampling four times higher than SAURON (0.27" vs. 0.94" spatial elements), resulting in almost a factor of two improvement in the median PSF. These data allow accurate study of the central regions to complement the large-scale view provided by SAURON. Here we present the stellar and gas kinematics, stellar absorption-line strengths and nebular emission-line strengths for this sample. We also characterise the stellar velocity maps using the "kinemetry" technique, and derive maps of the luminosity-weighted stellar age, metallicity and abundance ratio via stellar population models. We give a brief review of the structures found in our maps, linking also to larger-scale structures measured with SAURON. We present two previously unreported kinematically-decoupled components (KDCs) in the centres of NGC3032 and NGC4382. We compare the intrinsic size and luminosity-weighted stellar age of all the visible KDCs in the full SAURON sample, and find two types of components: kiloparsec-scale KDCs, which are older than 8 Gyr, and are found in galaxies with little net rotation; and compact KDCs, which have intrinsic diameters of less than a few hundred parsec, show a range of stellar ages from 0.5 - 15 Gyr (with 5/6 younger than 5 Gyr), are found exclusively in fast-rotating galaxies, and are close to counter-rotating around the same axis as their host. (abridged)