cosmofct {cooltools}

Fast cosmology conversion functions

Description

Generates all 20 conversion functions between redshift (z), luminosity distance (dl), comoving distance (dc) and angular diameter distance (da), and lookback time (t = light travel time from specified redshift); based on the *celestial* package.

Usage

cosmofct(zmin = 0, zmax = 1, dz = 0.02, H0 = 70, OmegaM = 0.3, ...)

Arguments

zmin

minimum redshift for which the conversion functions are used

zmax

maximum redshift for which the conversion functions are used

dz

redshift interval on which the conversion functions are interpolated (default of 0.02 is normally largely sufficient)

H0

local Hubble constant in units of km/s/Mpc (default 70).

OmegaM

local normalised matter density (default 0.3).

...

other cosmological parameters accepted by cosdist of the *celestial* package. Defaults are OmegaL=1-OmegaM-OmegaR, OmegaR=0, w0=-1, wprime=0.

Value

Returns a list of 20 vectorized functions; e.g. dc2z to convert from comoving distance to redshift. Also contains the age of the universe at z=0. All distances are in units of Mpc and times are in units of Gyr.

Author(s)

Danail Obreschkow (based on *celestial* package by Aaron Robotham)

Examples

## uses a flat LCDM cosmology with h=0.68, OmegaM=0.32 and OmegaL=0.68
cosmo = cosmofct(0,1,H0=68,OmegaM=0.32)
curve(cosmo$z2dl(x),0,1,xlab='z',ylab='distance',col='red')
curve(cosmo$z2dc(x),0,1,col='black',add=TRUE)
curve(cosmo$z2da(x),0,1,col='blue',add=TRUE)
d = seq(500,5000,500)
points(cosmo$dl2z(d),d,pch=16,col='red')
points(cosmo$dc2z(d),d,pch=16,col='black')
points(cosmo$da2z(d),d,pch=16,col='blue')