A CROSS-CORRELATION METHOD FOR SURFACE PHOTOMETRY

We apply the cross-correlation technique familiar in spectral matching to the two-dimensional case of surface photometry of galaxies with low surface brightness, i.e. to a problem of surface photometry with low signal-to-noise ratio. Comparison with normal profiling methods shows a considerable improvement in the accuracy with which photometric parameters can be obtained. In particular, for simulated images representing objects like GP 1444a which are fairly large but have extremely low surface brightness, we find errors of only approximately 2 and 3 per cent in the scalelength and central intensity, smaller by a factor approximately 6 than the errors obtained from intensity profiles.