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tabextinct - extinct a spectrum
tabextinct [parameter=value]
tabextinct takes a model extinction curve (defined as a simple
table with C as function of wavelength) and applies it to an input spectrum.
Although the model MUST have the wavelength and extinction in columns 1
and 2, the columns in the input spectrum can be selected. The output is
a simple table with only two columns: wavelength and extincted spectrum.
A spline interpolation is used into the extinction curve to find the appropriate
extinction at the requested wavelenghts of the spectrum. Therefore the extinction
model should cover the whole spectrum, currently the program does not allow
otherwise. Extincton occurs with the standard formulae
S = S0 . 10**(-0.4 * Av * C(lambda))
Using xscale= and yscale= the input spectrum can be scaled to match that
of the model.
This program can also be used to multiply two curves with
each other, using extinct=f.
The following parameters are recognized
in any order if the keyword is also given:
- model=
- Extinction model (table
with C(wave) in col 1/2)
- in=
- Input spectrum table file [???]
- xcol=
- Wavelength
column for spectrum [1]
- ycol=
- Flux column for spectrum [2]
- xscale=
- Scale factor applied to input spectrum wavelength in order to match that
of the model. [Default 1]
- yscale=
- Scale factor applied to input spectrum
flux for your preferred flux scaling. [Default: 1]
- xmin=
- (Wavelength) value
below which no data are printed or used. This is useful if your input spectrum
has a broad range you are not interested in. Default: not used
- xmax=
- (Wavelength)
value above which no data are printed or used. Default: not used
- Av=
- Av
to apply extinction curve with [1]
- extinct=
- Extinction law (t), or a simple
linear law (f) [Default: t]
% tabextinct model=model1.tab in=spectrum.tab Av=2.3 > spectrum23.tab
tabfilter(1NEMO)
, tabmath(1NEMO)
http://www.astro.princeton.edu/~draine/dust/dustmix.html example extincton tables
Peter Teuben
13-May-05 V0.1 Created on Friday 13th, so don’t expect too much PJT
16-may-06 V0.3 added xmin/xmax PJT
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