NAME
flx2tab - Read an input text file with one or more model spectra and
convert to an XSPEC table model file.
USAGE
flx2tab infile modelname tabfile nspec parinfofile additive
redshift xunit yunit clobber
DESCRIPTION
This tool reads a text file (infile) containing one or more spectra and
converts them into an XSPEC table model file (tabfile) so they can be used as a
model to fit to data. The input text file should have one line for each
bin of the spectrum. Each line should have at least three numbers. The
first two should be the start and end energy (or wavelength) of the
bin and the third the flux. If multiple spectra are to be read then
the flux for the second spectrum will be the fourth number and so
forth. The bins must be contiguous i.e. the end energy (or wavelength)
of one bin must be the same as the start energy (or wavelength) as the
next. The nspec parameter is used to specify the number of spectra to
read so the text file should have nspec+2 numbers per line.
If multiple spectra are read then an additional input text file
(parinfofile) is required to describe the model parameter information
and values for which the input spectra were calculated. This text file
should be as follows: the first line contains the parameter name; the
second line should be 0 (for linear interpolation) or 1 (for log
interpolation); the third line contains the six numbers for parameter
start value, delta, low, bottom, top, high (these are the numbers
shown by eg the XSPEC newpar command); the last line contains the
nspec parameter values used to generate the tabulated spectra.
The units for the energies (or wavelengths) and fluxes in the input
text file can be specified using the xunit and yunit parameters. The
allowed units are given below in the parameter specifications.
PARAMETERS
- infile [filename]
- The name of the input text file with the model spectrum or spectra.
- modelname [string]
- The name which will be used in XSPEC for the model.
- tabfile [filename]
- The name of the output XSPEC table model file.
- nspec [int]
- The number of model spectra in the input text file.
- parinfofile [filename]
- The name of the text file containing information on the
parameter. This is only required if nspec is greater than 1.
- additive [bool]
- If additive = yes then the table model is additive, if not it is multiplicative.
- redshift [bool]
- If redshift = yes then the table model will include a redshift parameter.
- xunit [string]
- The units for energy or wavelength used in the input text
file. The allowed options are keV (the default), MeV, GeV, Hz,
angstrom, cm, micron, or nm.
- yunit [string]
- The units for flux used in the input text file. This is not used
if the model is multiplicative. The allowed options are ph/cm^2/s (the
default), ph/cm^2/s/MeV, ph/cm^2/s/GeV, ph/cm^2/s/Hz, ph/cm^2/s/A,
ph/cm^2/s/cm, ph/cm^2/s/um, ph/cm^2/s/nm, ergs/cm^2/s, ergs/cm^2/s/Hz,
ergs/cm^2/s/A, ergs/cm^2/s/cm, ergs/cm^2/s/um, ergs/cm^2/s/nm, or Jy.
- clobber [bool]
- If clobber = yes then overwrite the output file if a file of this
name already exists.
EXAMPLES
1. Suppose we have a single spectrum which we wish to use as a model
in XSPEC. We create an text input file, myinput.txt :
0.1 0.2 1.3
0.2 0.3 1.4
0.3 0.4 1.8
0.4 0.5 0.9
0.5 0.6 0.8
0.6 0.7 1.0
0.7 0.8 0.5
0.8 0.9 0.3
0.9 1.0 0.1
and make the table model file by :
flx2tab myinput.txt MyModel mytable.fits
2. Suppose we have a model with a single parameter, alpha, and we
calculate spectra for alpha values of 1, 2, 3, 4, 5. We create the
input text file as in the previous example except there are now five
columns of fluxes. We also create a parameter information file,
myparfile.txt :
alpha
0
3.0 0.1 1.0 1.0 5.0 5.0
1.0 2.0 3.0 4.0 5.0
and make the table model file by :
flx2tab myinput.txt MyModel mytable.fits nspec=5 parinfofile=myparfile.txt
If we want to have XSPEC add a redshift parameter for the model then
we make the table model file by :
flx2tab myinput.txt MyModel mytable.fits nspec=5
parinfofile=myparfile.txt redshift=yes
3. As the previous case except that our spectra are in units of ergs/cm^2/microns
calculated in wavelength bins given in microns.
flx2tab myinput.txt MyModel mytable.fits nspec=5
parinfofile=myparfile.txt xunit=micron yunit=ergs/cm^2/um redshift=yes
SEE ALSO
XSPEC atable
and mtable
commands. The file
format for XSPEC table models.
LAST MODIFIED
Oct 2012