idlastro / Astronomical Utilities: MAG2FLUX

[Source code]

NAME
MAG2FLUX
PURPOSE
Convert from magnitudes to flux (ergs/s/cm^2/A). 
EXPLANATION
Use FLUX2MAG() for the opposite direction.
CALLING SEQUENCE
flux = mag2flux( mag, [ zero_pt, ABwave = ] )
INPUTS
mag - scalar or vector of magnitudes
OPTIONAL INPUT
zero_pt - scalar giving the zero point level of the magnitude.
        If not supplied then zero_pt = 21.1 (Code et al. 1976)
       Ignored if the ABwave keyword is set.
OPTIONAL KEYWORD INPUT
ABwave - wavelength scalar or vector in Angstroms.   If supplied, then 
         the input vector, mag, is assumed to contain Oke AB magnitudes
         (Oke & Gunn 1983, ApJ, 266, 713)
OUTPUT
flux - scalar or vector flux vector, in erg cm-2 s-1 A-1
      If the ABwave keyword is set, then the flux is given by
      f = 10^(-0.4*(mag +2.406 + 4*alog10(ABwave)))     
      Otherwise the flux is given by
      f =  10^(-0.4*(mag + zero_pt))
EXAMPLE
Suppose one is given vectors of wavelengths and AB magnitudes, w (in
Angstroms) and mag.   Plot the spectrum in erg cm-2 s-1 A-1
IDL> plot, w, mag2flux(mag,ABwave = w)
REVISION HISTORY
Written    J. Hill        STX Co.       1988
Converted to IDL V5.0   W. Landsman   September 1997
dded ABwave keyword,   W. Landsman   September 1998