Data Reduction Frequently Asked Questions
What is the meaning and use of the parameter UseResponseFlat in the FlatStrategy actor?
The transmission/reflection behaviour of the dichroics, that separate the wavelength regions for the three X-shooter arms, sometimes varies on short time scales. In consequence the flat fields for the standard star and for the science target may differ in the overlap regions. Therefore the workflow is set to use by default the flat field taken for the science data also for the standard star (UseResponseFlat=false). However, there may also be cases, where this setting results in spurious features in the flux calibrated data (see the X-Shooter Reflex tutorial for more details).
In such cases one should also check the results of the flux calibration using the standard star flat field to calibrate the standard star observation (UseResponseFlat=true).