  Roth et al (2014a) reported evidence for plumes of water venting from a
southern high latitude region on Europa - spectroscopic detection of off-limb
line emission from the dissociation products of water. Here, we present Hubble
Space Telescope (HST) direct images of Europa in the far ultraviolet (FUV) as
it transited the smooth face of Jupiter, in order to measure absorption from
gas or aerosols beyond the Europa limb. Out of ten observations we found three
in which plume activity could be implicated. Two show statistically significant
features at latitudes similar to Roth et al, and the third, at a more
equatorial location. We consider potential systematic effects that might
influence the statistical analysis and create artifacts, and are unable to find
any that can definitively explain the features, although there are reasons to
be cautious. If the apparent absorption features are real, the magnitude of
implied outgassing is similar to that of the Roth et al feature, however the
apparent activity appears more frequently in our data.
