XMM-Newton Data Files Handbook

4.1.5 EPIC PN science files

The following EPIC PN Science Files are defined:

1. Imaging Mode Event List Files (*PN*IME.FIT)

2. Timing Mode Event List Files (*PN*TIE.FIT)

3. Burst Mode Event List Files (*PN*BUE.FIT)

4. Auxiliary Files (*PN*AUX.FIT)

5. Offset Data Image Files (*PN*ODI.FIT)

6. Noise Data Image Files (*PN*NOI.FIT)

7. Discarded Lines Image Files (*PN*DLI.FIT)

8. Counting Cycle Report Auxiliary Files (*PN*CCX.FIT)

These are all binary table files. All except type 6 are used in the standard data analysis. The content of types 1-4 will be described below.

Type 5 (Offset Data Image) files contain the offset maps taken on board at the start of each exposure. The offset maps contain the per pixel energy offsets for each active CCD of the configured mode; during the exposure, these offsets are subtracted on board from the measured signals.

Type 6 (Noise Data Image) files are used for diagnostic purposes and are not required for standard data analysis. They contain the per pixel offset variance.

Type 7 (Discarded Lines Image) files are present in those cases where cosmic rays have hit a PN CCDs. They contain information on the number of lines blanked as a result of a detected cosmic ray interaction.

Type 8 (Counting Cycle Report) auxiliary files provide a summary record of the data lost when the telemetry rate is exceeded by the data rate produced by the PN cameras (i.e., when the PN is operated in so-called Counting Mode).

Types 7 and 8 are required in the standard data reduction for a proper exposure correction.

As for the other XMM-Newton instruments, the PN ODF files do not explicitly contain a column TIME. PN imaging, timing and burst modes contain a "Frame Counter", that increments monotonically in steps of 1 for the full detector. The ODF/SDF contain no time information in UT units, this has to be calculated using the time correlation file.

It is important to note that the above modes do not map one-to-one with the instrument modes defined in [16]. In particular:

• the ``Full Window'', ``Large Window'', and ``Small Window'' instrumental modes produce Imaging Mode Event List Files. While in Full and Large Window, all CCDs are used (for Large Window only half of the area of each chip is read out), only a part of CCD4 is used in Small Window.

• the ``Timing'' instrumental mode produces Timing Mode Event List data (from one chip). In the timing mode, imaging is made only in one dimension, along the column (RAWX) axis. Along the row direction (RAWY axis), data from a predefined area on one CCD chip are collapsed into a one-dimensional row to be read out at high speed. The RAWY axis is thus not a spatial coordinate, but is equivalent to time.

• A special flavour of the timing mode of the PN is the ``burst'' mode, which offers high time resolution of 7$\mu$s, but has a low duty cycle of 3%.

• Auxiliary files are produced for every instrumental mode

The above files can be recognised by the value of the keyword DATATYPE in their binary table header, as indicated in Table 3.