XMM-Newton Science Analysis System
eregionanalyse (especget-1.54) [xmmsas_20190531_1155-18.0.0]
By default the exposure time used for converting counts to count rate
is read from the EXPOSURE keyword in the header of the source
image. An exposure map may be introduced by the exposuremap
parameter in which case the exposure time is taken as the
value at the central pixel of the source region within the exposure map.
XMM-Newton SOC/SSC -- 2019-06-02