Exposure maps have header with strange numbers

computes exposure maps for survey or pointed observations of one or several eROSITA telescopes and energy bands.
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jessicapilling
Posts: 4
Joined: Wed Jul 19, 2023 10:46 am

Exposure maps have header with strange numbers

Post by jessicapilling »

Hello,

I have used expmap to generate an exposure map for an eFEDS field.
The command I used is as follows:
expmap inputdatasets=300009-clean_evts.fits templateimage=300009_combined_0.2-10.0keVimg.fits emin=0.2 emax=10.0 mergedmaps=300009_combined_0.2-10.0keVexpmap.fits

I have noticed that the header of the exposure map generated by this command contains some keywords with values that are of order 10^-314 and 10^-154
Specifically the keywords:
REFXCRVL, REFXCDLT, REFXLMIN, REFXDMAX, REFYCRVL, REFYCDLT, REFYLMIN, REFYDMAX

The numbers are so small I was wondering if this was an intended behaviour?

Thank you for the help!
IanStewart
Posts: 4
Joined: Fri Jul 28, 2023 9:05 am

Re: Exposure maps have header with strange numbers

Post by IanStewart »

Hi Jessica, almost certainly these values were not initialized in the code and therefore contain whatever random value was in the memory before. These particular keywords should have no effect on your data, but this of course should not happen, so I'll check the latest version of the task to make sure it does not in the next release.

Cheers Ian.
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