摘要：We present MUSE integral field spectroscopic data of the S0 galaxy NGC 3115 obtained
during the instrument commissioning at the ESO Very Large Telescope (VLT). We analyse the
galaxy stellar kinematics and stellar populations and present two-dimensional maps of
their associated quantities. We thus illustrate the capacity of MUSE to map extra-galactic
sources to large radii in an efficient manner, i.e. ~4 Re, and provide
relevant constraints on its mass assembly. We probe the well-known set of substructures of
NGC 3115 (nuclear disc, stellar rings, outer kpc-scale stellar disc, and spheroid) and
show their individual associated signatures in the MUSE stellar kinematics and stellar
populations maps. In particular, we confirm that NGC 3115 has a thin fast-rotating stellar
disc embedded in a fast-rotating spheroid, and that these two structures show clear
differences in their stellar age and metallicity properties. We emphasise an observed
correlation between the radial stellar velocity, V, and the Gauss-Hermite
moment, h3, which creates a butterfly shape in the
central 15′′ of the
h3 map. We further detect the previously
reported weak spiral- and ring-like structures, and find evidence that these features can
be associated with regions of younger mean stellar ages. We provide tentative evidence for
the presence of a bar, although the V-h3 correlation can be reproduced by a
simple axisymmetric dynamical model. Finally, we present a reconstruction of the
two-dimensional star formation history of NGC 3115 and find that most of its current
stellar mass was formed at early epochs (>12 Gyr ago), while star formation continued
in the outer (kpc-scale) stellar disc until recently. Since z ~2 and within
~4 Re, we suggest
that NGC 3115 has been mainly shaped by secular processes.
关键词：galaxies: elliptical and lenticular, cD;galaxies: evolution;galaxies: formation;galaxies: kinematics and dynamics;galaxies: stellar content;galaxies: structure
