F19

class dust_extinction.parameter_averages.F19(Rv=3.1, **kwargs)

Bases: BaseExtRvModel

Fitzpatrick et al (2019) extinction model calculation

Fitzpatrick, Massa, Gordon et al. (2019, ApJ, 886, 108) model. Based on a sample of stars observed spectroscopically in the optical with HST/STIS.

Parameters:

Rv: float

R(V) = A(V)/E(B-V) = total-to-selective extinction

Raises:

InputParameterError

Input Rv values outside of defined range

Notes

F19 Milky Way R(V) dependent extinction model

Example showing F19 curves for a range of R(V) values.

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

from dust_extinction.parameter_averages import F19

fig, ax = plt.subplots()

# temp model to get the correct x range
text_model = F19()

# 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 = F19(Rv=cur_Rv)
   ax.plot(x,ext_model(x),label='R(V) = ' + str(cur_Rv))

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

# for 2nd x-axis with lambda values
axis_xs = np.array([0.1, 0.12, 0.15, 0.2, 0.3, 0.5, 1.0])
new_ticks = 1 / axis_xs
new_ticks_labels = ["%.2f" % z for z in axis_xs]
tax = ax.twiny()
tax.set_xlim(ax.get_xlim())
tax.set_xticks(new_ticks)
tax.set_xticklabels(new_ticks_labels)
tax.set_xlabel(r"$\lambda$ [$\mu$m]")

ax.legend(loc='best')
plt.show()

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

Attributes Summary

Rv_range
x_range

Methods Summary

evaluate(in_x, Rv)

F19 function

Attributes Documentation

Rv_range = [2.0, 6.0]

x_range = [0.3, 8.7]

Methods Documentation

evaluate(in_x, Rv)

F19 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