IAU Symposium Abstract S186-058P

Anisotropy and dark mass in the elliptical galaxy NGC 6703

Ortwin Gerhard1, Gunther Jeske2,
R.P.~Saglia3, Ralf Bender3
1 Astronomisches Institut, Venusstr.~7, CH-4102 Binningen
2 Landessternwarte, K\"onigstuhl, D-69117 Heidelberg
3 Inst.~f\"ur Astronomie, Scheinerstr.~1, D-81679 M\"unchen

The absorption line velocity profiles in the spectra of elliptical galaxies contain important information on the anisotropy and the mass distribution of these systems (see Gerhard 1993, Merritt 1993). We here present the results of an extensive analysis of the E0 galaxy NGC 6703. This is part of an observational and theoretical program aimed at understanding the orbit structure and dark matter content of ellipticals (a preliminary account is given in Saglia et al.\ 1997). Our kinematic data for NGC 6703 extend to 2.6 Re. They can not be fit by any constant-M/L model - this galaxy must have a dark halo. For the maximal stellar M/L, the dark mass begins to dominate at R ~ 10 kpc. The orbit distribution is isotropic at the centre, radially anisotropic out to ~ 2 Re, and not well-determined near the data boundary.