**References** - 'Astrophysics of Dust in Cold Clouds' by B.T. Draine: http://arxiv.org/abs/astro-ph/0304488 - 'Interstellar Dust Grains' by B.T. Draine: http://arxiv.org/abs/astro-ph/0304489 Note that much of the code in this module is adapted from Erik Tollerud's `Astropysics <https://github.com/eteq/astropysics>`_, which has an Apache licence. """ from utilities import get_data_path import numpy as np datapath = get_data_path() PATH_EXTINCT = datapath + '/dust_extinction/' def starburst_Calzetti00(wa, EBmV, Rv=4.05): """ Dust extinction in starburst galaxies using the Calzetti relation. Find the extinction as a function of wavelength for the given E(B-V) using the relation from Calzetti et al. R_v' = 4.05 is assumed (see equation (5) of Calzetti et al. 2000 ApJ, 533, 682) E(B-V) is the extinction in the stellar continuum. The wavelength array wa must be in Angstroms and sorted from low to high values. Parameters
""" This module has routines for analysing the absorption profiles from ions and molecules. """ import math from math import pi, sqrt import numpy as np import voigt from convolve import convolve_psf from utilities import between, adict, get_data_path, indexnear from constants import Ar, me, mp, kboltz, c, e, sqrt_ln2, c_kms from spec import find_wa_edges DATAPATH = get_data_path() def calctau(v, wav0, osc, gam, logN, T=None, btemp=20, bturb=0, debug=False, verbose=True): """ Returns the optical depth (Voigt profile) for a transition. Given an transition with rest wavelength wav0, osc strength, natural linewidth gam; b parameter (doppler and turbulent); and log10 (column density), returns the optical depth in velocity space. v is an array of velocity values in km/s. The absorption line must be centred at v=0. Parameters ---------- v : array of floats, shape (N,) Velocities in km/s. wav0 : float Rest wavelength op transition in Angstroms.