A Shared Tully-Fisher Relation for Spiral and S0 Galaxies

Abstract

We measure the Tully-Fisher relations of 14 lenticular galaxies (S0s) and 14 spirals. We use two measures of rotational velocity. One is derived directly from observed spatially-resolved stellar kinematics and the other from the circular velocities of mass models that include a dark halo and whose parameters are constrained by detailed kinematic modelling. Contrary to the naive expectations of theories of S0 formation, we find no significant difference between the Tully-Fisher relations of the two samples when plotted as functions of both brightness and stellar mass.

To appear in Galaxy Evolution: Emerging Insights and Future Challenges, ed. S. Jogee et al., Astron. Soc. Pacific, 2009; v2 fixes minor typos