Cosmology
Cosmology library for Julia
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Cosmology calculator for Julia
Installation
To install the package:
pkg> add Cosmology
Then, to load into your session:
julia> using Cosmology
Cosmology.jl uses Unitful.jl and
UnitfulAstro.jl to handle units.
Cosmological Models
First, pick a cosmological model using the cosmology function,
which takes the following options:
| h = 0.69 | Dimensionless Hubble constant |
| OmegaK = 0 | Curvature density, Ωk |
| OmegaM = 0.29 | Matter density, Ωm |
| OmegaR = Ωγ + Ων | Radiation density, Ωr |
| Tcmb = 2.7255 | CMB temperature (K), used to compute Ωγ |
| Neff = 3.04 | Effective number of massless neutrino species, used to compute Ων |
| w0 = -1 | CPL dark energy equation of state, w = w0 + wa*(1-a) |
| wa = 0 | CPL dark energy equation of state, w = w0 + wa*(1-a) |
julia> using Cosmology
julia> c = cosmology()
FlatLCDM(0.69,0.7099122024007928,0.29,8.779759920715362e-5)
julia> c = cosmology(OmegaK=0.1)
OpenLCDM(0.69,0.1,0.6099122024007929,0.29,8.779759920715362e-5)
julia> c = cosmology(w0=-0.9, OmegaK=-0.1)
ClosedWCDM(0.69,-0.1,0.8099122024007929,0.29,8.779759920715362e-5,-0.9,0.0)
Distances
| angular_diameter_dist(cosmo, z) | Ratio of an object's proper transverse size (in Mpc) to its angular size (in radians) |
| comoving_radial_dist(cosmo, z) | Comoving radial distance to redshift z, in Mpc |
| luminosity_dist(cosmo, z) | Bolometric luminosity distance, in Mpc |
| distmod(cosmo, z) | Distance modulus, in units of magnitude |
julia> using Cosmology
julia> c = cosmology(OmegaM=0.26)
FlatLCDM(0.69,0.7399122024007928,0.26,8.779759920715362e-5)
julia> angular_diameter_dist(c, 1.2)
1784.0089227105113 Mpc
For each function returning a unitful number, you can specify a different unit for the result as first argument to the function:
julia> luminosity_dist(c, 1.5)
11420.338287150073 Mpc
julia> luminosity_dist(u"Gpc", c, 1.5)
11.420338287150074 Gpc
Volumes
| comoving_volume_element(cosmo, z) | Comoving volume element out to redshift z, in Gpc3 |
| comoving_volume(cosmo, z) | Comoving volume out to redshift z, in Gpc3 |
julia> using Cosmology
julia> c = cosmology(OmegaM=0.26)
FlatLCDM(0.69,0.7399122024007928,0.26,8.779759920715362e-5)
julia> comoving_volume_element(c, 2.1)
46.74459228888612 Gpc^3
julia> comoving_volume(c, 0.6)
49.3633436631307 Gpc^3
julia> comoving_volume(u"ly^3", c, 0.6)
1.7127035381752994e30 ly^3
Times
| age(cosmo, z) | Age of the universe at redshift z, in Gyr |
| lookback_time(cosmo, z) | Difference between age at redshift 0 and age at redshift z, in Gyr |
julia> using Cosmology
julia> c = cosmology(OmegaM=0.26)
FlatLCDM(0.69,0.7399122024007928,0.26,8.779759920715362e-5)
julia> age(c, 1.2)
5.445600787626434 Gyr
julia> lookback_time(u"yr", c, 1.2)
8.761660748088268e9 yr
First Commit
09/29/2013
Last Touched
3 months ago
Commits
49 commits