barak.absorb.calc_tau_peak¶
- barak.absorb.calc_tau_peak(logN, b, wa0, osc)[source]¶
Find the optical depth of a transition at line centre assuming we are on the linear part of the curve of growth.
Parameters : logN : array_like
log10 of column density in cm^-2
b : float
b parameter in km/s.
wa0 : float
Rest wavelength of the transition in Angstroms.
osc : float
Transition oscillator strength.
Returns : tau0 : ndarray or scalar if logN is scalar
optical depth at the centre of the line
Notes
See Draine “Physics of the Interstellar and Intergalactic medium” for a description of how to calculate this quantity.