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From: kiran lakhchaura <kiru111184@gmail.com>
Subject: xspec projct model and soft proton background
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Date: Thu, 21 Jul 2011 00:42:13 +0530 Subject: xspec projct model and soft proton background From: kiran lakhchaura <kiru111184@gmail.com> To: Ignacio de la Calle <xmmhelp@sciops.esa.int>

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Dear Sir,

I am using the* xspec projct *model to perform the de-projected spectral
analysis of the spectra obtained from several annuli.
I also wish to model the soft proton component in these annuli spectra using
power-law models.
From the ESAS-cookbook I found out that to determine the soft proton
parameters in the mos1, mos2 and pn
spectra of the same source I will have to use different powerl-aw models
(because the soft proton proton parameters for
the three detectors are in general different) and will have to declare the
three spectra as three different groups.

My problem is the *projct* model requires me to put all the spectra of a
single annulus in the same group which means that
I will not be able to fit the soft proton parameters of the mos1, mos2 and
pn detectors using different power-law model.

I request you to please help me with this problem.


Regards,
-- 
Kiran
Research Scholar
DAA, TIFR,
Mumbai-05

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Dear Sir,<br><br>I am using the<b> xspec projct
</b>model to perform the de-projected spectral analysis of the spectra
obtained from several annuli.<br>I also wish to model the soft proton
component in these annuli spectra using power-law models.<br>
From the ESAS-cookbook I found out that to determine the soft proton parameters
in the mos1, mos2 and pn <br>spectra of the same source I will have to use
different powerl-aw models (because the soft proton proton parameters for
<br>
the three detectors are in general different) and will have to declare the three
spectra as three different groups.<br><br>My problem is the
<b>projct</b> model requires me to put all the spectra of a single
annulus in the same group which means that <br>
I will not be able to fit the soft proton parameters of the mos1, mos2 and pn
detectors using different power-law model.<br><br>I request you to
please help me with this problem.<br
clear="all"><br><br>Regards,<br>-- <br>
Kiran <br>Research Scholar<br>DAA,
TIFR,<br>Mumbai-05<br>

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Reply 1

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From: Jan-Uwe Ness <xmmhelp@sciops.esa.int> To: kiru111184@gmail.com Subject: Re: xspec projct model and soft proton background (PR#48277) Date: Thu Jul 21 14:45:42 2011

Dear Kiran,

 while we acknowledge that requiring the background model to be done using
different groups in xspec poses a constraint, the solution to your problem is
more likely to be found in xspec, and we don't have a workaround. While the MOS1
and MOS2 spectra are similar enough that the power law index could be linked
(but not the normalizations!), the pn index does not correlate well at all.

 We recommend to contact the Xspec team to see if they have a way around
the limitation.

 Sorry we can't be of more help.

 Best regards,
Jan-Uwe

--
Dr. Jan-Uwe Ness
XMM-Newton SOC
 

> Dear Sir,
> 
> I am using the* xspec projct *model to perform the de-projected spectral
> analysis of the spectra obtained from several annuli.
> I also wish to model the soft proton component in these annuli spectra
using
> power-law models.
> From the ESAS-cookbook I found out that to determine the soft proton
> parameters in the mos1, mos2 and pn
> spectra of the same source I will have to use different powerl-aw models
> (because the soft proton proton parameters for
> the three detectors are in general different) and will have to declare the
> three spectra as three different groups.
> 
> My problem is the *projct* model requires me to put all the spectra of a
> single annulus in the same group which means that
> I will not be able to fit the soft proton parameters of the mos1, mos2 and
> pn detectors using different power-law model.
> 
> I request you to please help me with this problem.
> 
> 
> Regards,
> -- 
> Kiran
> Research Scholar
> DAA, TIFR,
> Mumbai-05
>

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