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Abteilung Astronomie

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CALZ_UNRED Source code in calz_unred.pro

CALZ_UNRED

Name
     CALZ_UNRED
Purpose
     Deredden a galaxy spectrum using the Calzetti et al. (2000) recipe
Explanation
     Calzetti et al.  (2000, ApJ 533, 682) developed a recipe for dereddening
     the spectra of galaxies where massive stars dominate the radiation output,
     valid between 0.12 to 2.2 microns.     (CALZ_UNRED extrapolates between
     0.12 and 0.0912 microns.)
Calling Sequence
     CALZ_UNRED, wave, flux, ebv, [ funred, R_V = ]
Input Parameters
      WAVE - wavelength vector (Angstroms)
      FLUX - calibrated flux vector, same number of elements as WAVE
               If only 3 parameters are supplied, then this vector will
               updated on output to contain the dereddened flux.
      EBV  - color excess E(B-V), scalar.  If a negative EBV is supplied,
               then fluxes will be reddened rather than deredenned.
               Note that the supplied color excess should be that derived for
               the stellar  continuum, EBV(stars), which is related to the
               reddening derived from the gas, EBV(gas), via the Balmer
               decrement by EBV(stars) = 0.44*EBV(gas)
Output Parameters
      FUNRED - unreddened flux vector, same units and number of elements
               as FLUX.   FUNRED values will be zeroed outside valid domain
               Calz_unred (0.0912 - 2.2 microns).
Keyword Parameters
       R_V - Ratio of total to selective extinction, default = 4.05.
             Calzetti et al. (2000) estimate R_V = 4.05 +/- 0.80 from optical
             -IR observations of 4 starbursts.
Example
       Estimate how a flat galaxy spectrum (in wavelength) between 1200 A
       and 3200 A is altered by a reddening of E(B-V) = 0.1.
       IDL> w = 1200 + findgen(40)*50      ;Create a wavelength vector
       IDL> f = w*0 + 1                    ;Create a "flat" flux vector
       IDL> calz_unred, w, f, -0.1, fnew  ;Redden (negative E(B-V)) flux vector
       IDL> plot,w,fnew
Note
       Use the 4 parameter calling sequence if you wish to save the
               original flux vector.
Procedures Used
      POLY()
Revision History
       Written   W. Landsman        Raytheon  ITSS   December, 2000

Last modified by pro2html on 2001 April 26 at 03:10 UTC

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Jörn Wilms (wilms@astro.uni-tuebingen.de)
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