XMM-Newton Science Analysis System
eposcorr (eposcorr-3.13) [xmmsas_20211130_0941-20.0.0]
task reads the X-ray source positions from an input
fits-file and correlates those with the positions from an optical source
The correlation algorithm checks whether there are offsets in RA and DEC
which optimize the correlation. To do this a particular statistic is used and
its value calculated for a grid of 30x30 offset values with a resolution, which
can be controlled by input parameters. If demanded a similar grid search
is done for roll angle errors. In that case, first a 3dimensional grid search
will be done and then several iterations with alternating RA/DEC offsets and
rotational offsets are made.
The optimum offsets are then used to correct the
input source positions which will be added as separate columns to
input X-ray source catalogue.
XMM-Newton SOC -- 2021-11-30