 Visible and Near Infrared Atlas of the Arcturus Spectrum, 3727-9300 A

    Kenneth Hinkle, Lloyd Wallace, Jeff Valenti, and Dianne Harmer



                   DESCRIPTION OF THE CD-ROM



This CD-ROM contains the spectra displayed on the atlas pages formatted
in ASCII and FITS.  In addition, the line lists printed in the
Appendices are included.  The data is divided into 64 files.  Since
the number of files is quite small all the files are in the main
directory.  The following readme file is a copy of the "Description of
the CD-ROM" printed on pages 375-377 of the atlas.



                     Data in ASCII format

The ASCII data is broken up into files covering 100 Angstroms with each
file labeled arnnnn, where nnnn is the approximate starting wavelength
for the file.  In each file the first column contains the wavelength,
the second is the Arcturus spectrum, the third is the solar flux
spectrum, and the fourth is the telluric transmission spectrum used to
correct the solar flux spectrum.  Both Arcturus and the solar flux
spectrum have been corrected for telluric absorption and in regions
where the correction was poor "-1." has been substituted.  In addition,
regions of the Arcturus spectrum suspected to be affected by detector
blemishes have been flagged by a minus sign in front of the spectral
value.



                     Data in FITS format

Two fits formats are provided.  The best wavelength accuracy is
provided by the data in FITS binary table extension format.  This data
is contained on the file ardata.fits.  However, for many IRAF users
multispec format is much more readable.  The multispec data is found in
files arcturus.fits, solarflux.fits, and telluric.fits.



                    FITS Multispec Format

On the CD-ROM the files arcturus.fits, solarflux.fits, and
telluric.fits contain data from columns two through four of the ASCII
files ar3700 through ar9200.  These FITS files are in IRAF
"multispec" format, with a sixth order polynomial fit to the
wavelength scale encoded in the FITS header. The maximum error in this
polynomial representation of the original wavelength scale is 0.24 mA.

To plot these FITS multispec data in IRAF, use SPLOT in the ONEDSPEC
package. For example, the spectral segments shown in Figure 4 can be
plotted as follows:

  cl> noao
  no> onedspec
  on> splot arcturus.fits xmin=3930 xmax=3938
  on> splot solarflux.fits xmin=3930 xmax=3938



               FITS Binary Table Extension Format

On the CD-ROM the file ardata.fits contains all data from the ASCII
files ar3700 through ar9200, merged into a single FITS file. This FITS
file consists of a null primary data unit (NAXIS=0) with a trivial
primary data header that serves only to flag the existence of an
extension (EXTEND=T). The first and only FITS extension is a binary
table with four columns, named WAVELENGTH, ARCTURUS, SOLARFLUX, and
TELLURIC, corresponding to the four columns in the ASCII files ar3700
through ar9200.


To read the FITS binary table data into IDL, use the astronomy library
function MRDFITS(). For example, the spectral segments shown in Figure
4 can be plotted as follows:

  IDL> atlas = mrdfits('ardata.fits', 1)
  IDL> help, atlas
  ATLAS           STRUCT    = -> <Anonymous> Array[762078]
  IDL> help, atlas, /str
  ** Structure <91e30>, 4 tags, length=24, refs=1:
     WAVELENGTH      DOUBLE           3726.7000
     ARCTURUS        FLOAT          0.440800
     SOLARFLUX       FLOAT          0.726200
     TELLURIC        FLOAT           1.00000
  IDL> iwhr = where(abs(atlas.wavelength-3934) le 4)
  IDL> plot, atlas(iwhr).wavelength, atlas(iwhr).arcturus
  IDL> plot, atlas(iwhr).wavelength, atlas(iwhr).solarflux

To read and plot the binary table data with IRAF, use the TABLES
package. For example, the spectral segments shown in Figure 4 can be
plotted as follows:

  cl> tables
  ta> ttools
  tt> tinfo ardata.fits
  # ardata.fits[1]
  762078 rows written to table
     4 columns defined
    29 header parameters written to table
    35 records allocated for header parameters
     4 space allocated for column descriptors
  table type:  fits
  tt> tlcol ardata.fits[1]
  # ardata.fits[1]
  WAVELENGTH       D           %9.4f ""              
  ARCTURUS         R           %7.4f ""              
  SOLARFLUX        R           %7.4f ""              
  TELLURIC         R           %7.4f ""              
  tt> sgraph "ardata.fits[r:wavelength=3930:3938] wavelength arcturus"
  tt> sgraph "ardata.fits[r:wavelength=3930:3938] wavelength solarflux"





                             Line Lists


The primary line lists used in labeling the spectra were organized with
blended constituents listed separately to form the appendices to the
atlas.  These appendices appear on the CD-ROM as the ASCII files appi,
appii, and  appiii.   appi is the atomic line list,  appii the CN line
list, and  appiii the CH and MgH line list.




                           Volume I Data


The data for Volume I (Infrared Atlas of the Arcturus Spectrum, 0.9-5.3
microns) is available on the AAS CD-ROM series.  The data can be found
on CD-ROM Number 5 at volume5/pasp/v107/p1402.

