XRT analysis guide


Please check the official XRT analysis guide for full details about XRT analysis. This document just contains some notes that are useful to me.

Getting started

In order to use the XRT catalog to find data, it's necessary to install the XRT branch of SSWDB. However, this directory contains a sub-directory called 'l1q_synop' that is very large (> 10 GB!), so I've set up my installation to only install the following sub-directories:

xrt_genxcat
xrt_genxcat_sirius

For the XRT routines to find data on your computer, you need to use the environment variable $XRT_ARCHIVE.

For the routine 'xrt_jitter' to work, it's necessary to have the SSWDB directory 'hinode/gen'.

XRT catalog

This is accessed by doing:

IDL> xrt_cat, t0, t1, catx, ofiles

for a suitable time range [t0,t1]. The catalog is stored in 'catx', which is a structure array. Each element of 'catx' corresponds to a XRT file, and the optional output 'ofiles' contains the full path specification of the files, assuming they're available on your computer.

The XRT team don't seem to provide any way of filtering the catalog into different filter and data types, so I've written a routine called 'xrt_cat_summary' that does this:

IDL> xrt_cat_summary, catx

This prints information about all the 'normal' files (i.e., not dark frames) in 'catx', and then prints a summary of the different types of unique file in 'catx'. With this information you can then produce a list of files belonging to a particular type:

IDL> xrt_cat_summary, catx, ofiles, type=type, outfiles=outfiles

where 'type' is an integer corresponding to the summary information, and 'outfiles' contains the list of files belonging to the specified type. The files can then be read with read_xrt:

IDL> read_xrt, outfiles, index, data

XRT temperature response functions

The following commands generate temperature response functions for XRT for a specific time.

IDL> xrt_wave_resp=make_xrt_wave_resp(contam_time='9-feb-2011 09:00')
IDL> xrt_temp_resp=make_xrt_temp_resp(xrt_wave_resp,/apec_default)

'xrt_temp_resp' is an IDL structure containing the responses for all the filters. For example, if you want Al-poly, then do:

IDL> print, xrt_temp_resp[1].name
Al-poly; XRT default emission model (APED/APEC 2007-May-17)
IDL> plot,xrt_temp_resp[1].temp,xrt_temp_resp[1].temp_resp,/xlog,xra=[1e5,1e8]

Note that the XRT analysis guide seems to recommend /apec_default, but /chianti_default is also available.

I provide a text file containing a description of how I derived temperatures for my paper Young & Muglach (2014, Sol. Phys.).


Page maintained by Dr Peter R Young.