APEC_nei_README.txt                             12 August 2010

     "Borkowski" APEC NEI files for use with XSPEC NEI models


* Summary of Files in this Directory:

BORK_APEC_nei_v11_comp.fits       -- cp --->  APEC_nei_v11_comp.fits
BORKfixed_APEC_nei_v11_line.fits  -- cp --->  APEC_nei_v11_line.fits

(Other related files:
  BORK_APEC_nei_v11_line.fits
  NOMINAL_APEC_nei_v11_comp.fits
  NOMINAL_APEC_nei_v11_line.fits  )


* Installing for XSPEC use

  To use these Borkowski files with XSPEC, download the first two
  files above and copy/rename them into the heasoft distribution as:

XSPEC 12 versions:
  cp BORK_APEC_nei_v11_comp.fits $HEADAS/../spectral/modelData/APEC_nei_v11_comp.fits
  cp BORKfixed_APEC_nei_v11_line.fits $HEADAS/../spectral/modelData/APEC_nei_v11_line.fits

(For older XSPEC installations the files went into: 
  yourxspecparentdirectory/lheasoft/spectral/xspec/manager  )


* Description

  XSPEC NEI models (vnei, vpshock, etc.) can take their atomic data from APEC data files
by setting NEIVERS to 2.0.
For isis users the command is:  isis>  xspec_xset ("NEIVERS", "2.0"); .

  The two APED-NEI files needed are made available on the XSPEC download page,
   http://heasarc.gsfc.nasa.gov/docs/software/lheasoft/download.html
where there's a little note just above the STEP 3 :
    Xspec Data For APEC NEI Models (19 Mb) -
           Needed only by XSPEC users running APEC NEI Models.
which links to:
  http://heasarc.gsfc.nasa.gov/FTP/software/lheasoft/release/xspec-nei-apec-data.tar.gz
This tar.gz file contains the two files APEC_nei_v11_comp.fits and 
APEC_nei_v11_line.fits which are listed above with a prepended "NOMINAL_".

  These files are known to be missing important lines and Kazik Borkowski
has made and provided improved versions of them[*], which are in this directory
prepended with "BORK_".  One of these, the lines one, has FITS issues
which John Houck of MIT took care of (strings were present instead of 
integers for some keywords); John created the "BORKfixed_" version
in this directory.

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[*] Kazik wrote (30 January 2006):
   ... my own version of the NEI code, where I added (some)
inner shell processes to NEI v2.0. You are welcome to try this out. All what
you need to do is to replace two files in your local XSPEC directory 

   yourxspecparentdirectory/lheasoft/spectral/xspec/manager

File names are APEC_nei_v11_line.fits and APEC_nei_v11_comp.fits. You may
want to save previous versions of the files. First file contains lines for
each ion, second file contains continua. You can find my most recent
versions of the files at

  http://astro.physics.ncsu.edu/~kborkow/nei/

The NEI v2.0 models are not default in XSPEC because of the lack of inner
shell processes. Your best bet is to go with my replacements for these files
until Randall Smith makes improvements to the code. In case you find them
useful and want to distribute them more broadly, please edit the header to
these files so that it is clear that these are not original APEC files -
this is important, as many atomic data in my additions are far from
reliable.

Please note that spectral lines and continua are all contained in these
files, and that additions/replacements to those files are not that difficult
(just time consuming). I think the best way to make reasonable progress is
for interested parties to make coordinated additions/replacements - a sort
of collaborative project where the work of gathering atomic data would be
redistributed among (hopefully) many people. This is an interim approach
until somebody like Randall Smith digs into atomic data much deeper. Just my
two cents.    Kazik
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