How to exclude regions when filtering

manipulate event files (pattern and flag selection, good time intervals application) and create images for survey or pointed observations of one or several eROSITA telescopes and energy bands.
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xPecax
Posts: 1
Joined: Fri Jun 03, 2022 5:26 pm

How to exclude regions when filtering

Post by xPecax »

Hello everyone,

I am trying to filter the eFEDS event files using the following basic expression:

Code: Select all

evtool eventfiles="fm00_300007_020_EventList_c001.fits" outfile="fm00_300007_020_EventList_c001_filtered.fits" 
region="ds9.reg"
The ds9.reg file is a simple circle:

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# Region file format: DS9 version 4.1
global color=green dashlist=8 3 width=1 font="helvetica 10 normal roman" select=1 highlite=1 dash=0 fixed=0 edit=1 move=1 delete=1 include=1 source=1
fk5
circle(8:41:45.8382,+2:36:36.253,2570.572")
And the task works. However, I would like to exclude the `ds9.reg` instead of excluding everything outside it. Basically, I want a hole in the region position. In DS9 this is done by simply adding a minus before the expression, like:

Code: Select all

-circle(8:41:45.8382,+2:36:36.253,2570.572")
But this does not work with `evtool`, and the final product is a black fits file when opened with DS9.

Any suggestion?
MiriamRamos
Posts: 23
Joined: Wed Jun 23, 2021 11:46 am

Re: How to exclude regions when filtering

Post by MiriamRamos »

Hello,

At the present, you can not do that with evtool. We hope that that feature will be included in the future. You could use some ftools or the xmm/chandra package for achieving what you want.

Best wishes,
Miriam
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