THE ASTRONOMICAL JOURNAL    VOLUME 108, NUMBER 1, PAGE 111            JULY 1994

                        THE INTRINSIC SHAPE OF NGC 3379

                               THOMAS S. STATLER

 Department of Physics and Astronomy, CB# 3255, University of North Carolina,
                    Chapel Hill, North Carolina 25799-3255
                     Electronic mail: tss@physics.unc.edu

                                   ABSTRACT
    
    Photometric and kinematic data from the literature are combined with
    new dynamical models to derive the intrinsic shape of the "standard"
    elliptical galaxy NGC 3379.  The parameters that are best constrained
    are the dynamical triaxiality T (essentially the triaxiality of the
    total mass distribution) and the short-to-long axis ratio of the light
    distribution c_L.  The inferred shape is given by a Bayesian
    probability distribution in the (T,c_L) plane.  Assuming a uniform
    prior, the most probable shape is oblate with a flattening of c_L=.87.
    The distribution is strongly non-Gaussian, however, and the expectation
    values, <T>=.31, <c_L>=.75, imply a flatter and more triaxial figure.
    The 68% highest posterior density region allows more triaxial shapes as
    long as they are fairly round, or flatter shapes as long as they are
    nearly oblate.  These results are essentially unchanged if the galaxy
    is assumed to rotate about its short axis, or if it is modeled as an S0
    with a negligible-mass disk rather than as an elliptical.  The
    suggestion of Capaccioli et al. [ApJ, 371, 535 (1991)] that NGC 3379 is
    a rather flat, triaxial S0 galaxy is found to be improbable at the 98%
    level; this conclusion is largely independent of the bulge-to-disk
    ratio or the relative rotation speeds of the two components.