The mass-L_x relation for moderate luminosity X-ray clusters
  We present measurements of the masses of a sample of 25 moderate X-ray
luminosity clusters of galaxies from the 160 square degree ROSAT survey. The
masses were obtained from a weak lensing analysis of deep F814W images obtained
using the Advanced Camera for Surveys (ACS). We present an accurate empirical
correction for the effect of charge transfer (in)efficiency on the shapes of
faint galaxies. A significant lensing signal is detected around most of the
clusters. The lensing mass correlates tightly with the cluster richness. We
measured the intrinsic scatter in the scaling relation between M_2500 and L_X
and find the best fit power law slope and normalisation to be alpha=0.68+-0.07
and M_X=(1.2+-0.12)10^14M_sun (for L_X=2x10^44 erg/s). These results agree well
with a number of recent studies, but the normalisation is lower compared to the
study of Rykoff et al. (2008b). One explanation for this difference may be the
fact that (sub)structures projected along the line-of-sight boost both the
galaxy counts and the lensing mass. Such superpositions lead to an increased
mass at a given L_X when clusters are binned by richness.
