Cosmos.jl

Pragmatic helpers for cosmology that wrap Cosmology.jl and expose default conversions, rich distance/time value types, and typed helpers for common Planck-like models.

Features

• CosmologicalModel keeps planck-compatible defaults, cached interpolation tables (distance/time ↔ redshift), and guards for optional parameters (e.g., baryons).
• Distance/time wrappers such as DistanceComoving, DistanceLightTravel, TimeLookback, and TimeConformal work with Redshift/ScaleFactor conversions out of the box.
• Typed conversion tables (NamedTuples) keep lookups fast and avoid repeated Dict allocations.
• CosmologyPlanck() seeds the default cosmology, so you can build conversions without wiring up parameters manually.

Getting started

using Cosmos

cosmo = CosmologyPlanck()
d = DistanceComoving(cosmo, 600u"Mpc")

redshift = d |> Redshift
scale = redshift |> ScaleFactor
luminosity = convert(DistanceLuminosity, d)

All distance/time conversions honour the cosmology stored in the value, so chained conversions stay consistent without re-specifying the model.

Distance & time helpers

Along with the conversion wrappers shown above, you can create a distance from two redshifts or scale factors:

z1 = Redshift(2.0)
z0 = Redshift(0.1)
dt = DistanceLightTravel(cosmo, z1, z0)

This package pre-builds monotonic interpolations between redshift and any supported measure to keep repeated lookups fast, so repeated DistanceXXX constructors reuse cached tables rather than recomputing cosmology integrals.

Tests & docs

• Run the bundled test suite with julia --project -e 'using Pkg; Pkg.test()'.
• Documentation is built with Documenter and lives at https://rafaelab.github.io/Cosmos.jl (see docs/src for the source).
• Example scripts live in examples/; each script is runnable via julia examples/name.jl to demonstrate common conversions.

Contributing

Fixes and extensions are welcome. Please keep tests green, prefer descriptive doc strings, and run Pkg.test() before opening a PR.

License

MIT © Rafael Abreu