unred

dust_extinction.conv_functions.unred(wave, flux, ebv, ext_model=None, R_V=3.1)[source]

Deredden or redden a flux vector using a specified extinction model.

This is a general function that can work with any extinction model that follows the dust_extinction interface.

Parameters:

  • wave (array_like) – Wavelength vector in Angstroms

  • flux (array_like) – Calibrated flux vector, same number of elements as wave

  • ebv (float) – Color excess E(B-V), scalar. If a negative EBV is supplied, then fluxes will be reddened rather than dereddened.

  • ext_model (extinction model, optional) – Extinction model instance (e.g., G23(Rv=R_V), F99(Rv=R_V)) If not specified, defaults to G23

  • R_V (float, optional) – Ratio of total to selective extinction, A(V)/E(B-V) Default is 3.1. Ignored if ext_model is provided.

Returns:

flux_corrected – Dereddened flux vector, same units and number of elements as flux

Return type:

ndarray

Raises:

ValueError – If wave and flux arrays have different sizes

Notes

Based on IDL astrolib routine CCM_UNRED, but using modern G23 extinction.

The correction applied is: F_corrected = F_observed * 10^(0.4 * A(λ) * E(B-V) * R_V)

where A(λ) is calculated from the specified extinction model.

Examples

>>> import numpy as np
>>> from dust_extinction.conv_functions import unred
>>>
>>> # Example wavelengths (3000-8000 Angstroms)
>>> wave = np.linspace(3000, 8000, 100)
>>> flux = np.random.random(100)  # Some mock flux values
>>> ebv = 0.1
>>>
>>> # General usage with default G23 model
>>> dereddened_flux = unred(wave, flux, ebv)
>>>
>>> # Using explicit model
>>> from dust_extinction.parameter_averages import F99
>>> f99_model = F99(Rv=3.1)
>>> dereddened_flux = unred(wave, flux, ebv, ext_model=f99_model)