Galactic stray light removal
The pickup of the Galactic signal through the sidelobes causes two kinds of systematic errors:
- It introduces a bias in the calibration process. - It leaves a spurious signal in the calibrated map.
The first error is corrected including an estimate of the Galactic sidelobe pickup alongside the convolved dipole in the fit with the measured voltages.
The second error is corrected subtracting the residual signal caused by Galactic pickup through the sidelobes from the timelines immediately after calibration.
[LFI meaning]: absolute calibration refers to the 0th order calibration for each channel, 1 single number, while the relative calibration refers to the component of the calibration that varies pointing period by pointing period.
