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Transformations

Extinction

By levaraging DustExtinction.jl we can apply common reddening laws to our spectra.

julia> using Unitful, Measurements, Random

julia> rng = Random.seed!(0);

julia> wave = (1:0.5:3)u"μm"
(1.0:0.5:3.0) μm

julia> sigma = randn(rng, size(wave))
5-element Vector{Float64}:
  0.942970533446119
  0.13392275765318448
  1.5250689085124804
  0.12390123120559722
 -1.205772284259936

julia> flux = (100 .± sigma)u"W/m^2/μm"
5-element Vector{Quantity{Measurement{Float64}, 𝐌 𝐋^-1 𝐓^-3, Unitful.FreeUnits{(μm^-1, m^-2, W), 𝐌 𝐋^-1 𝐓^-3, nothing}}}:
 100.0 ± 0.94 W μm^-1 m^-2
 100.0 ± 0.13 W μm^-1 m^-2
 100.0 ± 1.5 W μm^-1 m^-2
 100.0 ± 0.12 W μm^-1 m^-2
 100.0 ± -1.2 W μm^-1 m^-2

julia> spec = spectrum(wave, flux)
Spectrum(Quantity{Float64, 𝐋, Unitful.FreeUnits{(μm,), 𝐋, nothing}}, Quantity{Measurement{Float64}, 𝐌 𝐋^-1 𝐓^-3, Unitful.FreeUnits{(μm^-1, m^-2, W), 𝐌 𝐋^-1 𝐓^-3, nothing}})

julia> red = redden(spec, 0.3)
Spectrum(Quantity{Float64, 𝐋, Unitful.FreeUnits{(μm,), 𝐋, nothing}}, Quantity{Measurement{Float64}, 𝐌 𝐋^-1 𝐓^-3, Unitful.FreeUnits{(μm^-1, m^-2, W), 𝐌 𝐋^-1 𝐓^-3, nothing}})

julia> red.flux
5-element Vector{Quantity{Measurement{Float64}, 𝐌 𝐋^-1 𝐓^-3, Unitful.FreeUnits{(μm^-1, m^-2, W), 𝐌 𝐋^-1 𝐓^-3, nothing}}}:
 89.44 ± 0.84 W μm^-1 m^-2
 94.35 ± 0.13 W μm^-1 m^-2
  96.4 ± 1.5 W μm^-1 m^-2
 97.48 ± 0.12 W μm^-1 m^-2
  98.1 ± 1.2 W μm^-1 m^-2

julia> deredden!(red, 0.3)
Spectrum(Quantity{Float64, 𝐋, Unitful.FreeUnits{(μm,), 𝐋, nothing}}, Quantity{Measurement{Float64}, 𝐌 𝐋^-1 𝐓^-3, Unitful.FreeUnits{(μm^-1, m^-2, W), 𝐌 𝐋^-1 𝐓^-3, nothing}})

julia> red.flux ≈ spec.flux
true

API/Reference

DustExtinction.redden — Function
redden(::AbstractSpectrum, Av; Rv = 3.1, law = CCM89)

Redden a spectrum using common color laws provided by DustExtinction.jl. Av is the total extinction, Rv is the selective extinction (3.1 is a common value for the Milky Way) and law is the color law to use for determining the extinction.

source
DustExtinction.deredden — Function
deredden(::AbstractSpectrum, Av; Rv = 3.1, law = CCM89)

Deredden a spectrum using common color laws provided by DustExtinction.jl. Av is the total extinction, Rv is the selective extinction (3.1 is a common value for the Milky Way) and law is the color law to use for determining the extinction.

source