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XMM-Newton Science Analysis System

emevents (emevents-8.8) [xmmsas_20211130_0941-20.0.0]


emevents flags unvalid events (following evatt), subtracts bad pixels, merges events split over two nodes, separates piled up diagonal events into two, adds the time column and monitors the GATTI performance. It also modifies the RAWX and RAWY coordinates to center the events and computes camera coordinates. emevents modifies the number of events. Therefore after it the event file is not consistent with the NVALID field of the frame file any more. It may be applied as is to slew data.

As a preliminary step, emevents rejects events with invalid FRAME, RAWX, RAWY and PATTERN. Those are the result of telemetry errors. They are removed from the list altogether (not only flagged).

emevents calls (in order) the following subroutines, all of which can be individually switched off (this is provided for calibration and debugging activities, the result will not in general be scientifically useful when not used with the default settings):

EV_REC, CUT_BAD, DIAGO and BINODAL may run only on a fresh ODF event file, not on the result of a previous run of emevents.
PUT_TIME, CUT_GTI and SP_GATTI require an associated frame file. If frameset is not set then an empty EXPOSURE extension is created to allow propagating the CCD-specific keywords after evlistcomb.

SP_GATTI and REJECT_E3 require an associated offset/variance file or extension. It is also advised to provide it for CUT_BAD and BINODAL. As it is not always obvious to know which offsets file is the right one (if several modes were used in an observation, there will also be several offsets files with different exposure numbers), emevents will select among a list of offsets files those compatible with the events file in terms of CCD, node, mode and window parameters. Among the compatible files emevents will select that with DATE-OBS closest to DATE-OBS of the events file, first within the offsets files obtained before the events file, then within those obtained after the events file if none was obtained before.
The first and last four column offsets (in the window) are patched to 4095 as is done in operations.
If no local offset/variance file is available (because the standard values were used), or if offvarsetsis not set emevents will read the offsets from the cal. If the offsets actually used were different, this will result in a large number of spGatti11 warnings and the flagging of events with truncated energy will be wrong.

XMM-Newton SOC -- 2021-11-30