We present an I -band Tully-Fisher relation ( TFR ) for 18 nearby S0 galaxies using kinematics derived from long slit spectroscopy of stellar absorption lines .
Our estimates of the circular velocity , V _ { c } , at 2-3 exponential disk scale lengths account for line-of-sight projection and for the stellar random motions through an asymmetric drift correction .
Uniform and accurate distance calibration for all objects is available from surface brightness fluctuation measurements of Tonry et al .
( 1998 ) .
Despite the care taken in estimating both V _ { c } and M _ { I } , the TFR shows an intrinsic scatter , \sim 0.7 mag in M _ { I } , or 0.15 in { log } _ { 10 } V _ { c } .
This result is surprising , as S0 galaxies appear to have both the simple kinematics of disk galaxies , and the simple stellar populations of early-type galaxies .
Remarkably , in this sample of overall rotation-dominated galaxies , the central stellar velocity dispersion is a better predictor of the total I -band luminosity ( through the Fundamental Plane relations ) than the circular speed at several exponential scale lengths .
Furthermore , the TFR zeropoint , or the mean stellar I -band luminosity at a given V _ { c } , differs by only \sim 0.5 mag between our sample of S0s and Mathewson et al. ’ s ( 1992 ) sample of late-type spirals , once both data sets are brought onto a consistent distance scale .
This offset is less than expected if S0s are former spiral galaxies with prematurely truncated star-formation ( \mathrel { \raise 1.29 pt \hbox { $ > $ } \mkern - 14.0 mu \lower 2.58 pt \hbox { $ \sim$ } } 4 Gyrs ago ) .