  We obtain analytical expressions for the velocity anomaly due to the
Rossiter- McLaughlin effect, for the case when the anomalous radial velocity is
obtained by cross-correlation with a stellar template spectrum. In the limit of
vanishing width of the stellar absorption lines, our result reduces to the
formula derived by Ohta et al. (2005), which is based on the first moment of
distorted stellar lines. Our new formula contains a term dependent on the
stellar linewidth, which becomes important when rotational line broadening is
appreciable. We generate mock transit spectra for four existing exoplanetary
systems (HD17156, TrES-2, TrES- 4, and HD209458) following the procedure of
Winn et al. (2005), and find that the new formula is in better agreement with
the velocity anomaly extracted from the mock data. Thus, our result provides a
more reliable analytical description of the velocity anomaly due to the
Rossiter-McLaughlin effect, and explains the previously observed dependence of
the velocity anomaly on the stellar rotation velocity.
