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Re: [Fwd: a question about XRT]



Hello, Dr. Tan

1) I am copying this email to the XRT community. The "XRT_Users" email list is for users to help each other with questions like this.

http://xrt.cfa.harvard.edu/community/xrt_users/

2)�As you might know, there are 2 ways that filter data might be used to calculate the temperature and emission measure.�

2a) One way is with filter-ratios. This way only requires 2 filters, and assumes the plasma is isothermal. Some of our colleagues have developed some software for this, although it is not yet provided in the XRT SSWIDL tree. Narukage-san, can you speak to this? Is there a "xrt_teem.pro" program available?

2b) Another way is with DEM inversion. This way requires data in several nearly simultaneous filters (at least 4 or 5), but allows the plasma to be "multithermal" (ie, a superposition of many temperatures along the line of sight). The code for this is called "xrt_dem_iterative2.pro", and is located in the HINODE/XRT SSWIDL tree. There is a lot of documentation in the header of that program to explain its usage. However, it must assume that the user is already familiar with the concepts of DEM analysis.

Regards,
--Mark Weber

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From: Changyi Tan <ct45@njit.edu>
Date: March 13, 2009 9:51:29 AM EDT
Subject: a question about XRT


Dear Dr. Leon Golub,

� � I am Changyi Tan, from New Jersey Institute of Technology. I just have a question about dealing with XRT data. Is it possible to get the temperature and emission from images from different filters? If so, can you let me know the SSWIDL code? ��
��� Thanks.

--
Sincerely,
Changyi Tan
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Space Weather Research Laboratory, NJIT