  We present multiwaveband photometric and optical spectropolarimetric
observations of the R=15.9 narrow emission line galaxy R117_A which lies on the
edge of the error circle of the ROSAT X-ray source R117 (from McHardy et al
1998). The overall spectral energy distribution of the galaxy is well modelled
by a combination of a normal spiral galaxy and a moderate-strength burst of
star formation. The far infra-red and radio emission is extended along the
major axis of the galaxy, indicating an extended starburst.
  On positional grounds, the galaxy is a good candidate for the identification
of R117 and the observed X-ray flux is very close to what would be expected
from a starburst of the observed far infra-red and radio fluxes. Although an
obscured high redshift QSO cannot be entirely ruled out as contributing some
fraction of the X-ray flux, we find no candidates to K=20.8 within the X-ray
errorbox and so conclude that R117_A is responsible for a large fraction, if
not all, of the X-ray emission from R117.
  Searches for indicators of an obscured AGN in R117_A have so far proven
negative; deep spectropolarimetric observations show no signs of broad lines to
a limit of one per cent and, for the observed far infra-red and radio emission,
we would expect a ten times greater X-ray flux if the overall emission were
powered by an AGN. We therefore conclude that the X-ray emission from R117 is
dominated by starburst emission from the galaxy R117_A.
