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Name

tabextinct - extinct a spectrum

Synopsis

tabextinct [parameter=value]

Description

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.

Parameters

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]

Examples


  % tabextinct model=model1.tab in=spectrum.tab Av=2.3 > spectrum23.tab

See Also

tabfilter(1NEMO) , tabmath(1NEMO)

Files


http://www.astro.princeton.edu/~draine/dust/dustmix.html    example extincton tables

Author

Peter Teuben

Update History


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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