SBL18

class dust_attenuation.shapes.SBL18(x0=0.2175, gamma=0.035, ampl=0, slope=0.0, Av=1.0, **kwargs)

Bases: N09

Attenuation curve using a modified version of the Calzetti law allowing for a varying UV slope and the presence of a UV bump.

Parameters:

• Av (float) – attenuation in V band.

• x0 (float) – Central wavelength of the UV bump (in microns).

• gamma (float) – Width (FWHM) of thhe UV bump (in microns).

• ampl (float) – Amplitude of the UV bump.

• slope (float) – Slope of the power law.

Raises:

InputParameterError – Input Av values outside of defined range

Notes

Modification of N09 formalism: the UV bump was added before applying the power law correction in N09, in this class the UV bump is now added after the power law correction. This modification is first mentionned in in ApJ, Volume 859, Issue 1, article id. 11, 17 pp. (2018)

Example:

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

from dust_attenuation.shapes import SBL18

fig, ax = plt.subplots()

# generate the curves and plot them
x = np.arange(0.5,10,0.1)/u.micron

slopes = [-1, -0.5, 0, 0.5, 1]
for slope in slopes:
    att_model = SBL18(Av=1,ampl=3.5,slope=slope)
    ax.plot(x,att_model(1/x),label=r'$\delta$ = %.2f' % (slope))

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

ax.legend(loc='best')
plt.title("SBL18 with varying slopes")
plt.show()

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

Attributes Summary

x_range

Methods Summary

k_lambda(x, x0, gamma, ampl, slope)

Compute the starburst reddening curve k'(λ)=A(λ)/E(B-V) using recipe of Calzetti 2000 and Leitherer 2002

Attributes Documentation

x_range = [0.097, 2.2]

Methods Documentation

k_lambda(x, x0, gamma, ampl, slope)

Compute the starburst reddening curve k’(λ)=A(λ)/E(B-V) using recipe of Calzetti 2000 and Leitherer 2002

Parameters:

• in_x (np array (float)) – expects either x in units of wavelengths or frequency or assumes wavelengths in [micron] internally microns are used

• x0 (float) – Central wavelength of the UV bump (in microns).

• gamma (float) – Width (FWHM) of thhe UV bump (in microns).

• ampl (float) – Amplitude of the UV bump.

• slope (float) – Slope of the power law.

Returns:

k_lambda – k_lambda(x) reddening curve

Return type:

np array (float)

Raises:

ValueError – Input x values outside of defined range