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From: jjung11@alaska.edu
Subject: About evqpb
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Date: Tue, 5 Mar 2019 04:11:58 +0100
From: jjung11@alaska.edu
To: xmmhelp@sciops.esa.int
Subject: About evqpb
Full_Name: Jaewoong Jung
Submission from: (NULL) (193.147.152.102)


Dear XMM helpdesk team,

I'm trying to study magnetosheath background X-ray using XMM data. So I removed
point sources from event list file, using 

region -w 0 -V 0 eventset=PNclean.fits operationstyle=global
radiusstyle=userfixed fixedradius=35 srclisttab=emllist.fits
expression="ID_INST==0" outunit=detxy bkgregionset=PNout.fits

evselect -w 0 -V 0 table=PNclean.fits expression='region(PNout.fits,DETX,DETY)'
filteredset=PNcleanf.fits updatexposure=N writedss=Y withfilteredset=y
destruct=y keepfilteroutput=t

Here PNclean.fits is the result of proton flaring filtering, (I followed
https://www.cosmos.esa.int/web/xmm-newton/sas-thread-epic-filterbackground )
and emllist.fits are source list ( I followed 
https://www.cosmos.esa.int/web/xmm-newton/sas-thread-src-find-stepbystep -
actually I was not sure at this point because that article was written for MOS,
and I'm not sure I can use the same parameters.)

And to remove particle background, I used 

evqpb table=PNcleanf.fits exposurefactor=2.0 attfile=1744_0554370101_AttHk.ds
outset=evqpb_pn.fits 

to generate FWC file. Because already filtered for proton flaring, I didn't
filtered FWC file for proton flaring separately. (Or should I generate FWC file
first and do filtering flaring? Because then I should also do point source
removal separately.)

And I generated spectra from science file and FWC file, using

evselect table=PNcleanf.fits withspectrumset=y spectrumset=pnspec.fits
energycolumn=PI spectralbinsize=5 withspecranges=y specchannelmin=0
specchannelmax=20479 expression='(FLAG==0) && (PATTERN<=4) &&
((DETX,DETY) in
circle(0,0,16000))' withfilteredset=y filteredset=PNcleanfs.fits writedss=Y

evselect table=evqpb_pn.fits withspectrumset=y spectrumset=pnfwc_spec.fits
energycolumn=PI spectralbinsize=5 withspecranges=y specchannelmin=0
specchannelmax=20479 expression='(FLAG==0) && (PATTERN<=4) &&
((DETX,DETY) in
circle(0,0,16000))' withfilteredset=y filteredset=evqpb_pns.fits writedss=Y

However, I found out the total counts in my interested energy band (0.5-0.7keV)
for science spectrum (pnspec.fits) are LOWER than FWC spectrum
(pnfwc_spec.fits).
There should be some error in my procedure, I guess.

Can you point out what I did wrong, please?

Thanks,
Jaewoong


Reply 1

Resend
From: Simone Migliari <xmmhelp@sciops.esa.int>
To: jjung11@alaska.edu
Subject: Re: About evqpb (PR#84735)
Date: Thu Mar  7 10:23:03 2019
Dear Jaewoong

There is a threads that explains how to produce an instrumental background event
file tailored for a 
particular EPIC science exposure. The thread also shows how to produce a FWC
image and 
spectrum, and illustrates how they can be used to correct the science data for
instrumental 
background:

https://www.cosmos.esa.int/web/xmm-newton/sas-thread-background

Please check and follow this threads to see if you can obtain what you want. 

Also, about the use of the thread 
https://www.cosmos.esa.int/web/xmm-newton/sas-thread-src-
find-stepbystep, that is written for MOS, the only parameter that I see that  is
MOS-specific is in the 
expression of the evselect: 

For PN, you should change #XMMEA_EM  to #XMMEA_EP 

I hope this helps,
Kind Regards
Simone





> Full_Name: Jaewoong Jung
> Submission from: (NULL) (193.147.152.102)
> 
> 
> Dear XMM helpdesk team,
> 
> I'm trying to study magnetosheath background X-ray using XMM data. So I
removed
> point sources from event list file, using 
> 
> region -w 0 -V 0 eventset=PNclean.fits operationstyle=global
> radiusstyle=userfixed fixedradius=35 srclisttab=emllist.fits
> expression="ID_INST==0" outunit=detxy bkgregionset=PNout.fits
> 
> evselect -w 0 -V 0 table=PNclean.fits
expression='region(PNout.fits,DETX,DETY)'
> filteredset=PNcleanf.fits updatexposure=N writedss=Y withfilteredset=y
> destruct=y keepfilteroutput=t
> 
> Here PNclean.fits is the result of proton flaring filtering, (I followed
> https://www.cosmos.esa.int/web/xmm-newton/sas-thread-epic-filterbackground
)
> and emllist.fits are source list ( I followed 
> https://www.cosmos.esa.int/web/xmm-newton/sas-thread-src-find-stepbystep -
> actually I was not sure at this point because that article was written for
MOS,
> and I'm not sure I can use the same parameters.)
> 
> And to remove particle background, I used 
> 
> evqpb table=PNcleanf.fits exposurefactor=2.0
attfile=1744_0554370101_AttHk.ds
> outset=evqpb_pn.fits 
> 
> to generate FWC file. Because already filtered for proton flaring, I
didn't
> filtered FWC file for proton flaring separately. (Or should I generate FWC
file
> first and do filtering flaring? Because then I should also do point source
> removal separately.)
> 
> And I generated spectra from science file and FWC file, using
> 
> evselect table=PNcleanf.fits withspectrumset=y spectrumset=pnspec.fits
> energycolumn=PI spectralbinsize=5 withspecranges=y specchannelmin=0
> specchannelmax=20479 expression='(FLAG==0) && (PATTERN<=4)
&& ((DETX,DETY) in
> circle(0,0,16000))' withfilteredset=y filteredset=PNcleanfs.fits
writedss=Y
> 
> evselect table=evqpb_pn.fits withspectrumset=y spectrumset=pnfwc_spec.fits
> energycolumn=PI spectralbinsize=5 withspecranges=y specchannelmin=0
> specchannelmax=20479 expression='(FLAG==0) && (PATTERN<=4)
&& ((DETX,DETY) in
> circle(0,0,16000))' withfilteredset=y filteredset=evqpb_pns.fits
writedss=Y
> 
> However, I found out the total counts in my interested energy band
(0.5-0.7keV)
> for science spectrum (pnspec.fits) are LOWER than FWC spectrum
> (pnfwc_spec.fits).
> There should be some error in my procedure, I guess.
> 
> Can you point out what I did wrong, please?
> 
> Thanks,
> Jaewoong
> 
> 

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