Several recent numerical simulations of off-center cluster mergers predict
that significant angular momentum with associated velocities of a few x 10(
3) km s(-1) can be imparted to the resulting cluster. Such gas bulk velocit
ies can be detected by the Doppler shift of X-ray spectral lines with ASCA
spectrometers. Using two ASCA observations of the Centaurus cluster (Abell
3526), we produced a velocity map for the gas in the cluster's central regi
ons. We also detected radial and azimuthal gradients in temperature and met
al abundance distributions, which seem to be associated with the infalling
subgroup centered at NGC 4709 (Cen 45). More importantly, we found a signif
icant (>99.8% confidence level) velocity gradient along a line near-perpend
icular to the direction of the incoming subgroup and with a maximum velocit
y difference of similar to3.4 +/- 1.1 x 10(3) km s(-1). It is unlikely (P <
0.002) that the observed velocity gradient is generated by gain fluctuatio
ns across the detectors. While the observed azimuthal temperature and abund
ance variations can be attributed to the interaction with Cen 45, we argue
that the intracluster gas velocity gradient is more likely due to a previou
s off-center merging event in the main body of the Centaurus cluster.