extinction.fitzpatrick99(wave, a_v, r_v=3.1, unit='aa')

Fitzpatrick (1999) dust extinction function.

Fitzpatrick (1999) [1] model which relies on the parametrization of Fitzpatrick & Massa (1990) [2] in the UV (below 2700 A) and spline fitting in the optical and IR. This function is defined from 910 A to 6 microns, but note the claimed validity goes down only to 1150 A. The optical spline points are not taken from F99 Table 4, but rather updated versions from E. Fitzpatrick (this matches the Goddard IDL astrolib routine FM_UNRED).

wave : numpy.ndarray (1-d)

Input wavelengths or wavenumbers (see units).

a_v : float

Total V-band extinction in magnitudes.

r_v : float

Ratio of total to selective extinction, A_V / E(B-V).

unit : {‘aa’, ‘invum’}, optional

Wavelength units: Angstroms or inverse microns.

Extinction in magnitudes at each input wavelength.


[1]Fitzpatrick, E. L. 1999, PASP, 111, 63
[2]Fitzpatrick, E. L. & Massa, D. 1990, ApJS, 72, 163