J/AJ/108/111 J/AJ/108/111 NGC 3379 T S Statler Astron. J. 108 111 1994 1994AJ....108..111S Galaxies, optical 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.

NGC 3379UGC 590210 47.8 +12 35

Index Index to model parameters in tables 1,2,4 --- T Expectation value of dynamical triaxiality --- c_L Exp. value of flattening of light distrib. --- T_p Most probable value of T --- c_Lp Most probable value of c_L --- T_4 Maximum unprojected likelihood, T --- c_L4 Maximum unprojected likelihood, c_L --- phi_E4 Maximum unprojected likelihood, phi_E --- theta_E4 Maximum unprojected likelihood, theta_E --- table5.texAASTeX version of table5.dat Lee Brotzman ADS 1994Oct10Statler T.S. tss@physics.unc.edu Department of Physics and Astronomy, CB# 3255, University of North Carolina, Chapel Hill, North Carolina 25799-3255 AAS CD-ROM series, Volume 3, 1995 J_AJ_108_111.xml