XMM-Newton Science Analysis System
emenergy (emenergy-8.9) [xmmsas_20211130_0941-20.0.0]
- The flag map built by EVFLAG could be of interest to eexpmap
To that end it would need to be supplemented with small 5x5 maps
(one per pattern) describing the effective extension of a bad pixel.
Computing the area lost to bright pixels declared on-board is another matter.
It depends on energy, through the bright pixel level.
- If the telescope's attitude were to vary significantly
(more than the PSF) with time, then it should be considered using X,Y
(attitude corrected) as coordinates for CCDBKG, since
the optical background from stars would follow the attitude variations.
Note that this would need accumulating the map over a larger area than
the current window to accommodate pointing excursions.
The large scale optical background (e.g. stray light from the earth)
does not come through the telescope's optics and therefore has no reason
to follow the attitude variations. On the other hand it would be expected
to vary along the orbit.
The way to deal with that would be
to model the large scales (e.g. by a quadratic shape) separately
in several time bins and then model
the parameters' variations with time (quadratic).
- The subroutines CTI_CORR and ENERGY only call
the CAL routines CAL_mosCTIcorrection and CAL_gainCorrection.
- The scheme does not allow for the possibility of measuring the
gain in one observation (with the calibration source)
and passing this on to emenergy
(to supplement or replace the CAL).
- The baseline is to perform the ENERGY
subroutine at the end. It could also be considered
performing ENERGY (converting all E into PI)
This would be the best option if the ADU to PI conversion
were significantly non linear.
On the other hand it is somewhat more difficult to calibrate
and may induce some additional error.
XMM-Newton SOC -- 2021-11-30