XMM-Newton Data Center at MPE Create EPIC PN and MOS exposure map

Developped for XMMSAS version 5.3.0.

This page describes the XMMSAS task eexpmap that creates an exposure map for the EPIC (PN and MOS) detectors. The task uses the Current Calibration File Data (CCF data) of the spatial quantum efficiency, filter transmission, mirror vignetting, and the field of view. It needs the event file of the observation, and image file (preferably created by evselect due to header information as described on Simple Image page), and the attitude file. The task eexpmap has the following syntax:

   eexpmap eventset=P0059770101PNS003PIEVLI0000.FIT     \
           attitudeset=P0059770101OBX000ATTTSR0000.FIT  \
           imageset=image.fits expimageset=expo_map.fits
 

The default coordinate system of the exposure map is in sky pixel. The task eexpmap has a parameter withdetcoords which allows to create an exposure map also in Detector coordinates DETX, DETY, when the input image has been created in detector coordinates:

   eexpmap eventset=P0059770101PNS003PIEVLI0000.FIT     \
           attitudeset=P0059770101OBX000ATTTSR0000.FIT  \
           withdetcoords=true imageset=image_det.fits    \
	   expimageset=expo_map_det.fits 

Please note: For merged event files (as described on the Merge files page an exposure map by using eexpmap can only be created for the same detector. If you you use a merged event file of PN and MOS observations, it will not work. There is one way around: create the exposure maps separately for each detector and then combine them. It does work of course if you combine exposures of the same detector, e.g. for mosaic observations.

WARNING : In older versions of the XMMSAS a bug has been discovered that the exposure times calculated in the exposure map when using DETector coordinates depend on the binning of the input image! This problem does not apply anymore in the recent version 5.3.0.

© X-Ray Group at MPE (group)
last update:2008-01-14, editor of this page:Frank Haberl, Dirk Grupe