G16

class dust_extinction.parameter_averages.G16(*args, meta=None, name=None, **kwargs)

Bases: dust_extinction.baseclasses.BaseExtRvAfAModel

Gordon et al (2016) Milky Way, LMC, & SMC R(V) and f_A dependent model

Mixture model between the F99 R(V) dependent model (component A) and the G03_SMCBar model (component B)

Parameters

RvA: float

R_A(V) = A(V)/E(B-V) = total-to-selective extinction R(V) of the A component

fA: float

f_A is the mixture coefficent between the R(V)

Raises

InputParameterError

Input RvA values outside of defined range Input fA values outside of defined range

Notes

From Gordon et al. (2016, ApJ, 826, 104)

Example showing G16 curves for a range of R_A(V) values and f_A values.

import numpy as np
import matplotlib.pyplot as plt
import astropy.units as u

from dust_extinction.parameter_averages import G16

fig, ax = plt.subplots()

# temp model to get the correct x range
text_model = G16()

# generate the curves and plot them
x = np.arange(text_model.x_range[0],
              text_model.x_range[1],0.1)/u.micron

Rvs = ['2.0','3.0','4.0','5.0','6.0']
for cur_Rv in Rvs:
   ext_model = G16(RvA=cur_Rv, fA=1.0)
   ax.plot(x,ext_model(x),label=r'$R_A(V) = ' + str(cur_Rv) + '$')

ax.set_xlabel(r'$x$ [$\mu m^{-1}$]')
ax.set_ylabel(r'$A(x)/A(V)$')

ax.legend(loc='best', title=r'$f_A = 1.0$')
plt.show()

(Source code, png, hires.png, pdf)

import numpy as np
import matplotlib.pyplot as plt
import astropy.units as u

from dust_extinction.parameter_averages import G16

fig, ax = plt.subplots()

# temp model to get the correct x range
text_model = G16()

# generate the curves and plot them
x = np.arange(text_model.x_range[0],
              text_model.x_range[1],0.1)/u.micron

fAs = [0.0, 0.2, 0.4, 0.6, 0.8, 1.0]
for cur_fA in fAs:
   ext_model = G16(RvA=3.1, fA=cur_fA)
   ax.plot(x,ext_model(x),label=r'$f_A = ' + str(cur_fA) + '$')

ax.set_xlabel(r'$x$ [$\mu m^{-1}$]')
ax.set_ylabel(r'$A(x)/A(V)$')

ax.legend(loc='best', title=r'$R_A(V) = 3.1$')
plt.show()

(Source code, png, hires.png, pdf)

Attributes Summary

RvA_range
fA_range
x_range

Methods Summary

evaluate(in_x, RvA, fA)

G16 function

Attributes Documentation

RvA_range = [2.0, 6.0]

fA_range = [0.0, 1.0]

x_range = [0.3, 10.0]

Methods Documentation

static evaluate(in_x, RvA, fA)

G16 function

Parameters

in_x: float

expects either x in units of wavelengths or frequency or assumes wavelengths in wavenumbers [1/micron]

internally wavenumbers are used

Returns

axav: np array (float)

A(x)/A(V) extinction curve [mag]

Raises

ValueError

Input x values outside of defined range