XMM-Newton Science Analysis System
omfastshift (omfastshift-1.26) [xmmsas_20211130_0941-20.0.0]
- FAST mode data is not binned by the DPU. The drifts from the ODF OM
Tracking History Auxiliary File need to be corrected for BPE only.
- All events are assumed to occur in the centre of their pixel. The
output integer pixel coordinate value is the integer truncation of the real
- For FAST mode, in addition to a tracking frame time, a FAST mode time
slice (FMTS) is defined with duration SAMPTIME*10ms, where
SAMPTIME is integer (i.e. integer multiples of a CCD frame)
- Each event is tagged with a time stamp (FTCOARSE+FTFINE) corresponding
to the specific FMTS integration within each tracking frame
integration, in which each event occurred. This allows the possibility
to apply a `fine shift' to each event corresponding to the spacecraft
drift, after each FMTS integration.
- omfastshift produces by default a corrected event list in
which all events within a FMTS are shifted back to the reference frame
using drifts calculated from a linear interpolation of the tracking
frame drifts in the OM Tracking History auxiliary data file.
- A corrected event list in which all events within a tracking frame are
shifted back to the reference frame using the tracking frame drifts
can be called for by the setting flag interp_flag = F on the command
- It is worth noting that there exists cases in which a FMTS crosses a
tracking frame boundary. Although events may belong to two tracking
frames, all events within the FMTS are given the same event timestamp
and are treated equivalently.
- The drift-corrected OM FAST mode event list contains 4 additional
columns: the corrected X and Y pixel coordinates and OBT time for each event
and a flag denoting whether the shift-corrected event falls within the
defined science window. This flag is necessary since the s/c drift causes
the science window to sample a region of the sky larger than the science
window. When these events are drift-corrected they may fall outside
the GO defined science window area. A value of WIN_FLAG=0 is given for all
events outside the science window, and WIN_FLAG=1 for all events in
the science window.
- TLMIN and TLMAX are required by EVSELECT.
XMM-Newton SOC -- 2021-11-30