We present the first comparison of virial masses of galaxy clusters with their Sunyaev-Zel ’ dovich Effect ( SZE ) signals .
We study 15 clusters from the Hectospec Cluster Survey ( HeCS ) with MMT/Hectospec spectroscopy and published SZE signals .
We measure virial masses of these clusters from an average of 90 member redshifts inside the radius r _ { 100 } .
The virial masses of the clusters are strongly correlated with their SZE signals ( at the 99 % confidence level using a Spearman rank-sum test ) .
This correlation suggests that Y _ { SZ } can be used as a measure of virial mass .
Simulations predict a powerlaw scaling of Y _ { SZ } \propto M _ { 200 } ^ { \alpha } with \alpha \approx 1.6 .
Observationally , we find \alpha =1.11 \pm 0.16 , significantly shallower ( given the formal uncertainty ) than the theoretical prediction .
However , the selection function of our sample is unknown and a bias against less massive clusters can not be excluded ( such a selection bias could artificially flatten the slope ) .
Moreover , our sample indicates that the relation between velocity dispersion ( or virial mass estimate ) and SZE signal has significant intrinsic scatter , comparable to the range of our current sample .
More detailed studies of scaling relations are therefore needed to derive a robust determination of the relation between cluster mass and SZE .