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From: miranda@physics.umanitoba.ca
Subject: trouble with blank sky background for pn
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7 replies: 1 2 3 4 5 6 7
5 followups: 1 2 3 4 5

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Notification:


Date: Thu, 3 Aug 2006 18:26:55 GMT
From: miranda@physics.umanitoba.ca
To: xmmhelp@sciops.esa.int
Cc: miranda@physics.umanitoba.ca
Subject: trouble with blank sky background for pn
Full_Name: Miranda Jackson
Submission from: (NULL) (24.79.141.254)


I am having trouble generating blank sky background events files for pn using
skycast. For the first of two different observations of different regions of the
sky, skycast generated an event file from which I then extracted a background
spectrum, but the background spectrum shows an overabundance of counts at low
and high energies, and the background subtracted spectrum is not close to the
shape of the MOS spectra or the pn spectrum using a background from the same
observation.

For the second of two observations, skycast crashed the entire computer by using
up the memory and swapfile (I believe the computer has 1GB of memory and 4GB
swap). That happened twice, and the third time I was very careful and shut down
all other programs, and it ran for over a week and produced an events file which
appears to be corrupt in some way, because evselect returns the following
error:

** evselect: error (FITSIO), FITS error 107 while accessing file
'pnblksky2006_3.fits': tried to move past end of file
Error reading elements 1 thru 6813145 from column 1 (ffgcld).

Is there anything I can check to see what might be causing these problems? I
would really like to use blank sky backgrounds as I am analysing spectra of
diffuse emission of SNRs and background spectra extracted from the field
surrounding the objects vary widely depending on the particular region selected,
because of source contribution and varying instrumental emission lines over the
CCDs. The scripts and blank sky events files seem to work well for the MOS
instruments (though they do result in background subtracted spectra which are
difficult to fit and are not entirely consistent with each other), but there are
problems using them for pn. I am using the file PN.T.FF.EVLIRC.FIT as input to
skycast.

Thanks.


Reply 1

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From: Matthias Ehle <xmmhelp@sciops.esa.int>
To: miranda@physics.umanitoba.ca
Subject: Re: trouble with blank sky background for pn (PR#22801)
Date: Fri Aug  4 11:31:06 2006
Dear Miranda,

I am in contact with the skycast task developer and the collagues
who generated the blank-sky event lists. I will let you have results
of their analysis as soon as I get their reply.

Regards,
   Matthias

--
   Dr Matthias Ehle 
   XMM-Newton User Support Group
   European Space Astronomy Centre


Reply 2

Resend
From: Matthias Ehle <xmmhelp@sciops.esa.int>
To: miranda@physics.umanitoba.ca
Subject: Re: trouble with blank sky background for pn (PR#22801)
Date: Fri Aug  4 12:47:12 2006
Dear Miranda,

The experts are asking for additional information from you:

Could you supply, please, the exact sycast command line that you issued 
and any extra files that you used (i.e. your template event file)?

Afterwards they would be happy to try and recreate the problem and 
find a solution.

Many thanks in advance,
   Matthias


Followup 1

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Date: Fri, 04 Aug 2006 11:07:41 -0500
From: miranda@physics.umanitoba.ca
Subject: Re: trouble with blank sky background for pn (PR#22801)
To: Matthias Ehle <xmmhelp@sciops.esa.int>
Hello

Thank you for your reply. I used the following command (omitting paths):

skycast PN.T.FF.EVLIRC.FIT pn1_filtered.fits pnblksky2006.fits

The event file pn1_filtered.fits is rather large (nearly 70 MB). Would you like
me to email it to you anyway?


Thanks.
-- 
Miranda Jackson 
Department of Physics and Astronomy 
University of Manitoba
Phone: (204) 474-6187
Fax: (204) 474-7622
Email: miranda@physics.umanitoba.ca


Quoting Matthias Ehle <xmmhelp@sciops.esa.int>:

> Dear Miranda,
> 
> The experts are asking for additional information from you:
> 
> Could you supply, please, the exact sycast command line that you issued 
> and any extra files that you used (i.e. your template event file)?
> 
> Afterwards they would be happy to try and recreate the problem and 
> find a solution.
> 
> Many thanks in advance,
>    Matthias
> 


* WEB Mail, Department of Physics & Astronomy, University of Manitoba



Reply 3

Resend
From: Matthias Ehle <xmmhelp@sciops.esa.int>
To: miranda@physics.umanitoba.ca
Subject: Re: trouble with blank sky background for pn (PR#22801)
Date: Fri Aug  4 16:20:56 2006
Hi,

> The event file pn1_filtered.fits is rather large (nearly 70 MB). Would you
like
> me to email it to you anyway?

Can you put it on an anonymous ftp account at your site and let me know
how to download it, please?

Cheers,
  Matthias


Followup 2

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Date: Fri, 04 Aug 2006 12:16:07 -0500
From: miranda@physics.umanitoba.ca
Subject: Re: trouble with blank sky background for pn (PR#22801)
To: Matthias Ehle <xmmhelp@sciops.esa.int>
Hello

You can get the file here:
http://www.physics.umanitoba.ca/~miranda/pn1_filtered.fits

I don't know how to set up an anonymous ftp.

Thanks.
-- 
Miranda Jackson 
Department of Physics and Astronomy 
University of Manitoba
Phone: (204) 474-6187
Fax: (204) 474-7622
Email: miranda@physics.umanitoba.ca


Quoting Matthias Ehle <xmmhelp@sciops.esa.int>:

> Hi,
> 
> > The event file pn1_filtered.fits is rather large (nearly 70 MB). Would
you
> like
> > me to email it to you anyway?
> 
> Can you put it on an anonymous ftp account at your site and let me know
> how to download it, please?
> 
> Cheers,
>   Matthias
> 
> 


* WEB Mail, Department of Physics & Astronomy, University of Manitoba



Reply 4

Resend
From: Matthias Ehle <xmmhelp@sciops.esa.int>
To: miranda@physics.umanitoba.ca
Subject: Re: trouble with blank sky background for pn (PR#22801)
Date: Mon Aug  7 09:37:08 2006
Hello,

OK, thanks - I have informed our experts about the location of your file.

Cheers,
  Matthias


Reply 5

Resend
From: Matthias Ehle <xmmhelp@sciops.esa.int>
To: miranda@physics.umanitoba.ca
Subject: Re: trouble with blank sky background for pn (PR#22801)
Date: Mon Aug  7 12:36:39 2006
Hello Miranda,

Now I have received an answer from the expert:
---------------
   I can't reproduce the problem - It works fine for me - I downloaded the
pn1_filtered.fits file, and the PN.T.FF.EVLIRC.FIT file and the skycast script 
from the ESAC pages to make sure we were dealing with the same files.... 

Large files, yes, I agree, but it completed fine in about 8 minutes - the output

looks OK. I could make the final file available if you need. Perhaps the user
has 
disk space/memory problems? 
--------------

Cheers,
  Matthias


Followup 3

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Date: Mon, 07 Aug 2006 12:45:27 -0500
From: miranda@physics.umanitoba.ca
Subject: Re: trouble with blank sky background for pn (PR#22801)
To: Matthias Ehle <xmmhelp@sciops.esa.int>
Hello

Would it be possible for you to give me the md5sum of the PN.T.FF.... file so I
can check it against the file I downloaded?

Thanks.
-- 
Miranda Jackson 
Department of Physics and Astronomy 
University of Manitoba
Phone: (204) 474-6187
Fax: (204) 474-7622
Email: miranda@physics.umanitoba.ca


Quoting Matthias Ehle <xmmhelp@sciops.esa.int>:

> Hello Miranda,
> 
> Now I have received an answer from the expert:
> ---------------
>    I can't reproduce the problem - It works fine for me - I downloaded the
> pn1_filtered.fits file, and the PN.T.FF.EVLIRC.FIT file and the skycast
> script 
> from the ESAC pages to make sure we were dealing with the same files.... 
> 
> Large files, yes, I agree, but it completed fine in about 8 minutes - the
> output
> 
> looks OK. I could make the final file available if you need. Perhaps the
> user
> has 
> disk space/memory problems? 
> --------------
> 
> Cheers,
>   Matthias
> 
> 


* WEB Mail, Department of Physics & Astronomy, University of Manitoba



Reply 6

Resend
From: Matthias Ehle <xmmhelp@sciops.esa.int>
To: miranda@physics.umanitoba.ca
Subject: Re: trouble with blank sky background for pn (PR#22801)
Date: Tue Aug  8 07:57:25 2006
Dear Miranda,
> 
> Would it be possible for you to give me the md5sum of the PN.T.FF.... file
so
I
> can check it against the file I downloaded?

typing 'md5sum PN.T.FF.EVLIRC.FIT' I obtain
536899e005a916ccadf64d07ea0a665e  PN.T.FF.EVLIRC.FIT

Cheers,
  Matthias


Followup 4

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Date: Wed, 09 Aug 2006 12:05:36 -0500
From: miranda@physics.umanitoba.ca
Subject: Re: trouble with blank sky background for pn (PR#22801)
To: Matthias Ehle <xmmhelp@sciops.esa.int>
That matches the file I have here, so there must be something wrong with the
computer or memory I am using. Do you know how much memory the computer that
was used to test the script there has, and also how long the total computation
should take?
Thanks.
-- 
Miranda Jackson 
Department of Physics and Astronomy 
University of Manitoba
Phone: (204) 474-6187
Fax: (204) 474-7622
Email: miranda@physics.umanitoba.ca


Quoting Matthias Ehle <xmmhelp@sciops.esa.int>:

> Dear Miranda,
> > 
> > Would it be possible for you to give me the md5sum of the PN.T.FF....
file
> so
> I
> > can check it against the file I downloaded?
> 
> typing 'md5sum PN.T.FF.EVLIRC.FIT' I obtain
> 536899e005a916ccadf64d07ea0a665e  PN.T.FF.EVLIRC.FIT
> 
> Cheers,
>   Matthias
> 
> 


* WEB Mail, Department of Physics & Astronomy, University of Manitoba



Reply 7

Resend
From: Matthias Ehle <xmmhelp@sciops.esa.int>
To: miranda@physics.umanitoba.ca
Subject: Re: trouble with blank sky background for pn (PR#22801)
Date: Thu Aug 10 14:09:48 2006
Dear Miranda,

The computer we tested this on has:

2 x Intel Xeon 3.06GHz 512kB cache processor with 533Mhz FSB

4 x 1GB registered low profile DDR memory

We just retested it again, and it took 4 minutes to complete. All the script
does, 
is just copying the input file, extracting header information from the template

file, and then running attcalc on the copy of the input file. That's all.

Perhaps you could just run 'attcalc' on the PN.T.FF.EVLIRC.FIT file (or a copy 
of it), with

attcalc eventset=PN.T.FF.EVLIRC.FIT attitudelabel=fixed fixedra=$ra_pnt
fixeddec=$dec_pnt fixedposangle=$pa_pnt withatthkset=N refpointlabel=user
nominalra=$ranom nominaldec=$decnom

where:
$ra_pnt  = RA_PNT value in template file header
$dec_pnt = DEC_PNT value in template file header
$pa_pnt  = PA_PNT value in template file header
$ranom   = REFXCRVL value in template file header
$decnom  = REFYCRVL value in template file header 

Cheers,
   Matthias


Followup 5

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Date: Thu, 10 Aug 2006 17:41:51 -0500
From: miranda@physics.umanitoba.ca
Subject: Re: trouble with blank sky background for pn (PR#22801)
To: Matthias Ehle <xmmhelp@sciops.esa.int>
Thanks for the info. I thought that after a week the program might have been
running for too long. I will do as you advise and hopefully I'll have more luck
with both observations.

Thanks again.
-- 
Miranda Jackson 
Department of Physics and Astronomy 
University of Manitoba
Phone: (204) 474-6187
Fax: (204) 474-7622
Email: miranda@physics.umanitoba.ca


Quoting Matthias Ehle <xmmhelp@sciops.esa.int>:

> Dear Miranda,
> 
> The computer we tested this on has:
> 
> 2 x Intel Xeon 3.06GHz 512kB cache processor with 533Mhz FSB
> 
> 4 x 1GB registered low profile DDR memory
> 
> We just retested it again, and it took 4 minutes to complete. All the
script
> does, 
> is just copying the input file, extracting header information from the
> template
> 
> file, and then running attcalc on the copy of the input file. That's all.
> 
> Perhaps you could just run 'attcalc' on the PN.T.FF.EVLIRC.FIT file (or a
> copy 
> of it), with
> 
> attcalc eventset=PN.T.FF.EVLIRC.FIT attitudelabel=fixed fixedra=$ra_pnt
> fixeddec=$dec_pnt fixedposangle=$pa_pnt withatthkset=N refpointlabel=user
> nominalra=$ranom nominaldec=$decnom
> 
> where:
> $ra_pnt  = RA_PNT value in template file header
> $dec_pnt = DEC_PNT value in template file header
> $pa_pnt  = PA_PNT value in template file header
> $ranom   = REFXCRVL value in template file header
> $decnom  = REFYCRVL value in template file header 
> 
> Cheers,
>    Matthias
> 


* WEB Mail, Department of Physics & Astronomy, University of Manitoba


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