This page (revision-28) was last changed on 18-Apr-2021 19:17 by PeterYoung

This page was created on 16-Nov-2009 21:50 by PeterYoung

Only authorized users are allowed to rename pages.

Only authorized users are allowed to delete pages.

Page revision history

Version Date Modified Size Author Changes ... Change note
28 18-Apr-2021 19:17 9 KB PeterYoung to previous
27 08-Jul-2010 16:40 9 KB PeterYoung to previous | to last
26 08-Jul-2010 16:17 10 KB PeterYoung to previous | to last
25 08-Jul-2010 15:36 10 KB PeterYoung to previous | to last
24 08-Jul-2010 01:47 10 KB PeterYoung to previous | to last
23 09-Jun-2010 22:14 10 KB PeterYoung to previous | to last
22 09-Jun-2010 18:20 8 KB PeterYoung to previous | to last
21 07-Jun-2010 21:47 8 KB PeterYoung to previous | to last

Page References

Incoming links Outgoing links
NRLtest...nobody
NRLtest

Version management

Difference between version and

At line 1 changed one line
!!!A guide to accessing and analyzing EIS data
[{ALLOW edit EISMainUsers}]
[{ALLOW view Anonymous}]
%%(color:red;)__This page is still under construction. All of the information should be accurate, but some of the links are broken.__%%
At line 3 removed one line
This guide describes how to access, calibrate and derive scientific results from the EIS instrument on Hinode. For a description of EIS and its observing modes please consult the instrument paper, [Culhane et al. (2007)|http://adsabs.harvard.edu/abs/2007SoPh..243...19C], and the [MSSL Science Centre webpage|http://msslxr.mssl.ucl.ac.uk:8080/SolarB/].
At line 6 added 4 lines
!!!EIS data analysis guide
This guide describes how to access, calibrate and derive scientific results from the EIS instrument on Hinode. For a description of EIS and its observing modes please consult the instrument paper, [Culhane et al. (2007)|http://adsabs.harvard.edu/abs/2007SoPh..243...19C], and the [MSSL Science Centre webpage|https://vsolar.mssl.ucl.ac.uk/SolarB/].
At line 19 changed one line
[MSSL Science Centre (UK)|http://msslxr.mssl.ucl.ac.uk:8080/SolarB/]\\
[MSSL Science Centre (UK)|https://vsolar.mssl.ucl.ac.uk/SolarB/]\\
At line 80 changed one line
The 1" and 2" slits return emission line spectra and a basic task for such data-sets is to fit Gaussians to the emission lines to return intensity, centroid and width information. Gaussian fitting routines available to EIS users are described below. Interpretation of centroids and widths is hampered by certain instrumental effects and these are dealt with in the sections below.
The 1" and 2" slits return emission line spectra and a basic task for such data-sets is to fit Gaussians to the emission lines to return intensity, centroid and width information. Gaussian fitting routines available to EIS users are described below. The routines correct for most instrumental effects, but users should familiarize themselves with some of these effects through the software notes listed below:
At line 87 added 5 lines
* Warm and hot pixels (Software Notes 6 and 13)
* Orbital drift of line centroids (Software Note 5)
* EIS slit tilts (Software Note 4)
* EIS grating tilt (Software Note 3)
At line 84 changed one line
!Intensity maps
Fitting a Gaussian function to an emission line yields measures of the line intensity, centroid (velocity) and width. Single Gaussian fits to individual lines are possible using [EIS object methods|EISmethods], while more sophisticated fitting options are available through the EIS_AUTO_FIT and SPEC_GAUSS_EIS routines available in Solarsoft. Documents describing these routines and giving examples are listed below.
At line 86 changed one line
!Velocity maps
[Gaussian fitting for the Hinode/EIS mission|https://hyperion.nascom.nasa.gov/svn/eis/release/doc/fitting/eis_auto_fit.pdf]\\
[Gaussian fitting examples using eis_auto_fit|https://hyperion.nascom.nasa.gov/svn/eis/release/doc/fitting/eis_auto_fit_examples.pdf]
At line 88 removed one line
!Line width maps
At line 100 added 2 lines
Users should be aware that EIS line profiles can often take on non-Gaussian shapes which may contain valuable scientific information (e.g., [Chifor et al. 2008|http://adsabs.harvard.edu/abs/2008A%26A...481L..57C,], [De Pontieu et al. 2009|http://adsabs.harvard.edu/abs/2009ApJ...701L...1D,]).
At line 92 changed one line
!!Slot data (40", 266" slits)
Some emission line ratios are sensitive to the electron density, and software is available to take the line fit structures output by EIS_AUTO_FIT and convert them to electron density maps. The density then allows the emitting column depth of the plasma to be determined which in turn allows the filling factor of the plasma to be estimated. The document below describes how this done, making use of atomic data from the [CHIANTI database|http://www.chiantidatabase.org].
At line 94 changed one line
The EIS slots produce images rather than spectra, and the most common application will be to produce movies from the slot rasters in a range of emission lines. Diagnostics are possible with the slots, however, by taking ratios of images and temperature and density diagnostics are described below.
Deriving densities from Hinode/EIS data
At line 96 changed one line
!Making movies
!Emission measure
At line 98 changed one line
!Temperature diagnostics
When line intensities are available from several different ions, then an emission measure (EM) or differential emission measure (DEM) distribution can be constructed. No specific EIS software is available for doing this and so users are referred to software in the CHIANTI database, in particular:
At line 100 changed one line
!Density diagnostics
integral_calc.pro: computes an EM value from a single line intensity\\
chianti_dem.pro: computes a DEM distribution from multiple line intensities
At line 102 changed one line
!!Pointing and co-alignment
Another popular DEM code is available within the [PINTofALE|http://hea-www.harvard.edu/PINTofALE/] software package.
At line 104 removed one line
Most EIS users will be analyzing data-sets from multiple instruments and so it is necessary to determine where an EIS raster is positioned relative to the other instruments. Usually the pointing information within an EIS file will not be good enough to accurately co-align data-sets and so cross-correlation will be necessary.
At line 106 removed one line
!How to get the most accurate EIS coordinates
At line 108 changed one line
!EIS and IDL maps
!!Slot data (40", 266" slits)
At line 110 changed one line
The set of [IDL map software|http://beauty.nascom.nasa.gov/~zarro/idl/maps/maps.html] of D. Zarro is a popular means for handling solar image data. The situation is more complicated for EIS than imaging instruments as an image can be an intensity, velocity or line width map. EIS maps are generated from EIS data objects as follows (in the case of a velocity map from Fe XII 195.12):
The EIS slots produce images rather than spectra, and the most common application will be to produce movies from the slot rasters in a range of emission lines. Diagnostics are possible with the slots, however, by taking ratios of images and temperature and density diagnostics are described below.
At line 112 changed 3 lines
IDL> obj=obj_new('eis_data', filename)\\
IDL> m=obj_new('eis_moment',obj,iwin=195.12)\\
IDL> mmap=m->mk_eis_map(195.12,/vel)
!Making movies
At line 116 changed one line
The output mmap is in the standard format accepted by the map software.
!Temperature diagnostics
At line 118 changed one line
To generate an intensity map use keyword /int and for a line width map use /wid. When the 'eis_moment' object is created (step 2) a widget will pop up allowing you to define the spectral region containing the emission line. Moments are used to generate the velocity and line widths which ensures quick results. You can use Gaussian fitting by giving the additional keyword fit='gauss' in step 2 for the eis_moment call.
!Density diagnostics
At line 120 changed one line
!Cross-correlation with SOT and XRT
!!Pointing and co-alignment
At line 122 changed one line
!Cross-correlation with EIT and TRACE
Most EIS users will be analyzing data-sets from multiple instruments and so it is necessary to determine where an EIS raster is positioned relative to the other instruments. Usually the pointing information within an EIS file will not be good enough to accurately co-align data-sets and so cross-correlation will be necessary.
At line 133 added 5 lines
* [Obtaining pointing information from EIS data|EISPointing]
* [Creating an IDL map from EIS data|EISMaps]
* [Cross-correlating EIS and SOT images|EISSOTcoalign]
* [Cross-correlating EIS and XRT images|EISXRTcoaling]
This page (revision-28) was last changed on 18-Apr-2021 19:17 by PeterYoungTop