Left:V_Rd/R_d versus including rotating Sphs in the Virgo cluster (red diamonds). The other symbols are the same as in Fig. 1. The dashed line shows a linear fit to the Irr and BCD data (same as in Fig. 1). The stellar rotation velocities have been corrected for asymmetric drift (see Appendix A). Right: R_d against . The dashed lines correspond to exponential profiles with a fixed total magnitude (− 22, − 20, − 18, − 16, − 14, and − 12 R mag).