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Session 124 - Elliptical Galaxies.
Oral session, Saturday, January 10
We present deep multi-position-angle long-slit spectroscopy of the "standard elliptical" NGC 3379, obtained at the MMT. This system has long been regarded as a dynamically ordinary elliptical that rotates slowly about its apparent minor axis, though it has also been suspected on photometric grounds of being a nearly face-on S0. Our high-accuracy (10 km/s or better out to 1.7 effective radii) measurements of the stellar kinematic fields show weak but significant signatures of triaxiality, including slow rotation on the minor axis of 5 km/s amplitude. We present a statistical determination of the intrinsic shape of the system from dynamical modeling. In addition, we show that the kinematic fields share distinctive features, such as sign reversals of the h3 and h4 Gauss-Hermite coefficients, with those of comparably observed edge-on S0's. We assess the dynamical evidence for the presence of a hidden disk in NGC 3379.
Program listing for Saturday