[Ifeffit] Least Squares Fitting in Athena

Stanislav Stoupin stousta at iit.edu
Tue May 24 15:41:15 CDT 2005

Hello all,

I have a couple of comments about LSF in Athena and I would like to hear 
other people's opinions on the matter.
Also, it would be interesting to know: are there 
many people who use Athena to do LSF?

I found that there is some inconsistency with plotting after 
the fit is done. In my case nonzero energy shifts are applied to 
the fitted data and the standards. The resulting linear combination fit 
doesn't look shifted in energy appropriately - visually there is a 
mismatch between the data and the fit. On the other hand, R-factor and 
Chi^2 are very reasonable. This looks somewhat confusing.

Also, in my experience the obtained fractions in Athena come out slightly 
different from those I could get using Sixpack LSF software. In my fits I 
used the same constrains/options, same data and references and same data 
range. What can be the cause of this?


Stanislav Stoupin
Research Assistant/PhD student
BCPS department
Illinois Institute of Technology

email: stousta at iit.edu
voice: 312-567-7983

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