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Late-type galaxies observed with SAURON: two-dimensional stellar and emission-line kinematics of 18 spirals

2006; Oxford University Press; Volume: 367; Issue: 1 Linguagem: Inglês

10.1111/j.1365-2966.2005.09977.x

1365-2966

Katia Ganda, J. Falcón‐Barroso, R. F. Peletier, Michele Cappellari, Éric Emsellem, Richard M. McDermid, P. T. de Zeeuw, C. M. Carollo,

Astronomy and Astrophysical Research

We present the stellar and gas kinematics of a sample of 18 nearby late-type spiral galaxies (Hubble types ranging from Sb to Sd), observed with the integral-field spectrograph SAURON at the 4.2-m William Herschel Telescope. SAURON covers the spectral range 4800–5380 Å, allowing us to measure the Hβ, Fe, Mgb absorption features and the emission in the Hβ line and the [O iii]λλ4959, 5007 Å and [N i]λλ5198, 5200 Å doublets over a 33 × 41-arcsec2 field of view. The maps cover the nuclear region of these late-type galaxies and in all cases include the entire bulge. In many cases the stellar kinematics suggests the presence of a cold inner region, as visible from a central drop in the stellar velocity dispersion. The ionized gas is almost ubiquitous and behaves in a complicated fashion: the gas velocity fields often display more features than the stellar ones, including wiggles in the zero-velocity lines, irregular distributions, ring-like structures. The line ratio [O iii]/Hβ often takes on low values over most of the field, probably indicating a wide-spread star formation.