"""
Cosmological constants and utilities for redback-jax.
Usage::
from redback_jax.utils import PLANCK18_H0, PLANCK18_OM0, luminosity_distance_cm
"""
# Planck 2018 cosmology (Planck Collaboration 2018, A&A 641, A6)
PLANCK18_H0 = 67.66 # Hubble constant in km/s/Mpc
PLANCK18_OM0 = 0.3111 # Matter density parameter
MPC_TO_CM = 3.085677581e24 # cm per Mpc
[docs]
def luminosity_distance_cm(redshift, H0=PLANCK18_H0, Om0=PLANCK18_OM0):
"""Luminosity distance in cm.
Parameters
----------
redshift : float
Source redshift.
H0 : float, optional
Hubble constant in km/s/Mpc (default: Planck18).
Om0 : float, optional
Matter density parameter (default: Planck18).
Returns
-------
float
Luminosity distance in cm.
Examples
--------
>>> dl_cm = luminosity_distance_cm(0.01)
"""
from wcosmo import wcosmo as _wcosmo
return _wcosmo.luminosity_distance(redshift, H0, Om0).value * MPC_TO_CM