Cosmological conversions

GadgetUnits.jl supplied some conversion functions to convert observables in given cosmologies. These functions rely on Cosmology.jl, specifically a struct of AbstractCosmology.

Cosmology

To define an AbstractCosmology from the properties of the simulation you can use the multiple dispatch function

Cosmology.cosmology — Function

cosmology(h::AbstractGadgetHeader)

Defines a Cosmology.AbstractCosmology from the properties of h.

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Time

To get the current age of the universe you can use age

Cosmology.age — Function

age(h::AbstractGadgetHeader, units::Bool=false)

Computes the age of the universe given the properties from AbstractGadgetHeader.

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If the optional parameter units is set to true it will preserve the unit property. Otherwise it will return a Real in units Gyrs.

You can convert arcminutes to kpc for an object at redshift z with arcmin_to_kpc. This can be used either with a pre-defined Cosmology.AbstractCosmology or can use a AbstractGadgetHeader struct from GadgetIO.jl which defines the AbstractCosmology on the fly. If you input θ::Real the function will return kpc, but remove the unit property. Optionally you can define θ::Unitful.AbstractQuantity which preserves the unit property.

GadgetUnits.arcmin_to_kpc — Function

arcmin_to_kpc(c::Cosmology.AbstractCosmology, θ::Unitful.AbstractQuantity, z::Real)

Convert arcmin to kpc for a given redshift z and cosmology c. Conserves unit information.

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arcmin_to_kpc(c::Cosmology.AbstractCosmology, θ::Real, z::Real)

Convert arcmin to kpc for a given redshift z and cosmology c. Deletes unit information.

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arcmin_to_kpc(θ::Real, h::AbstractGadgetHeader)

Convert arcmin to kpc for a given redshift and cosmology taken from AbstractGadgetHeader.

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arcmin_to_kpc(θ::Unitful.AbstractQuantity, h::AbstractGadgetHeader)

Convert arcmin to kpc for a given redshift and cosmology taken from AbstractGadgetHeader.

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Radiation

To convert synchrotron radiation from mJy to W/Hz you can use mJy_to_W. Like in the case of Scale you can use either a pre-defined AbstractCosmology or use an AbstractGadgetHeader.

GadgetUnits.mJy_to_W — Function

mJy_to_W( c::Cosmology.AbstractCosmology, S::Unitful.AbstractQuantity, z::Real )

Converts synchrotron flux density S in [mJy] to [W/Hz] for a given redshift z and cosmology c. Conserves unit information.

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mJy_to_W( c::Cosmology.AbstractCosmology, S::Real, z::Real )

Converts synchrotron flux density S in [mJy] to [W/Hz] for a given redshift z and cosmology c. Deletes unit information.

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mJy_to_W(S::Union{Real, Unitful.AbstractQuantity}, h::AbstractGadgetHeader)

Converts synchrotron flux density S in [mJy] to [W/Hz] for a given redshift and cosmology taken from AbstractGadgetHeader.

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mJy_to_W(S::Union{Real,Unitful.AbstractQuantity}, d::Unitful.AbstractQuantity)

Converts synchrotron flux density S in [mJy] to [W/Hz] for a given distance d.

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mJy_to_W(S::Union{Real,Unitful.AbstractQuantity}, d::Real)

Converts synchrotron flux density S in [mJy] to [W/Hz] for a given distance d in [Mpc].

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mJy_to_W(S::Union{Real,Unitful.AbstractQuantity}, d::Real)

Converts synchrotron flux density S in [mJy] to [W/Hz] for a given distance d in [Mpc].

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