[Loops] On the importance of background subtraction in the analysis of coronal loops observed with TRACE

[Gary, Gilmer A. (MSFC-VP62)]

Markus,

A question --- has anyone tried to model "all" the loops in some manner so that the "background" variation for  a loop could be removed using time dependencies of all the individual loops (or a major set of loops)?

This would be a temporal  stereographic reconstruction and would be as arduous, but some STEREO sets might lead to interesting results. The matrix inversions might however by ill-posed and some special math might be neeeded. Anyway  a thought that was generaqted from your commmet.

Someone might  use some analytic test cases or examples might lead to some specific ideas for real observations.

Best regards,
Allen
 
________________________________________
From: loops-bounces at solar.physics.montana.edu [loops-bounces at solar.physics.montana.edu] On Behalf Of Markus J. Aschwanden [aschwanden at lmsal.com]
Sent: Monday, February 15, 2010 5:02 PM
To: A mailing list for scientists involved in the observation and modeling of solar loop structures
Subject: Re: [Loops] On the importance of background subtraction in the analysis of coronal loops observed with TRACE

Sergio and Fabio,

I like to encourage you to use STEREO EUVI data, which would provide
you the ultimate test to subtract the correct background, because you
see a loop from two different directions and have two independent
backgrounds. You can test the self-consistence of background subtraction,
if you obtain the same EM of the loop from two spacecraft.
If you look into my recent STEREO paper, you see that one can
subtract the background with an accuracy of about 10%.
See Fig.8 therein.

Cheers,
Markus

 Aschwanden,M.J., Nitta,N.V., Wuelser,J.P., and Lemen,J.R. 2008, The Astrophysical Journal, 680, 1477-1495
URL1="http://www.lmsal.com/~aschwand/eprints/2008_stereo2.pdf"<http://www.lmsal.com/~aschwand/eprints/2008_stereo2.pdf>
First 3D reconstructions of coronal loops with the STEREO A and B spacecraft: II. Electron Density and Temperature Measurements