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    Deredden a galaxy spectrum using the Calzetti et al. (2000) recipe


    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 = ]


      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)


      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).

Optional Input Keyword

      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.


      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


      Use the 4 parameter calling sequence if you wish to save the
              original flux vector.

Procedure Calls


Revision History

      Written W. Landsman Raytheon ITSS December, 2000

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