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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.


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.

--Mark Weber


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?   

Changyi Tan
Space Weather Research Laboratory, NJIT