The dynamics of the dE galaxy FS76 : bridging the kinematic dichotomy between Es and dEs
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We present major and minor axis kinematics out to 2 half-light radii for the bright (M_B=-16.7) dwarf elliptical FS76, a member of the NGC5044 group. Its velocity dispersion is 46 \pm 2 km/s in the center and rises to 70 \pm 10 km/s at half-light radius. Beyond 1R_e the dispersion starts to fall again. The maximum rotation velocity is 15 \pm 6 km/s, about the value expected for an oblate isotropic rotator with the same flattening as FS76 (dE1). Hence, FS76 is the first dE discovered so far that is not flattened predominantly by anisotropy. Using dynamical models, we estimate the mass-to-light ratio to be between 3.2 and 9.1, consistent with predictions based on CDM cosmological scenarios for galaxy formation.
8 pages, 2 figures, submitted to ApJL
8 pages, 2 figures, submitted to ApJL