Produce the effective area file 'output.arf' (with PSF correction applied) using the spectrum
'sw00073125003xpcwnposr.pha' obtained filtering a Photon Counting mode event file on a spatial
region centered on the source position.
Get all the calibration files needed to perform the computation from the Calibration
> xrtmkarf outfile=output.arf phafile=sw00073125003xpcwnposr.pha
srcx=-1 srcy=-1 psfflag=yes