pynbody.analysis.cosmology

Functions for common cosmological calculations.

Functions

H(f)	Calculate the Hubble parameter of the universe in snapshot f
add_hubble(f)	Add the hubble flow to velocities in snapshot f
age(f[, z, unit])	Calculate the age of the universe in the snapshot f by integrating the Friedmann equation.
comoving_to_physical(ar)	Given an array, modify it to be in physical units (remove any dependencies on a or aform).
linear_growth_factor(f[, z])	Calculate the linear growth factor b(a), normalized to 1 at z=0, for the cosmology of snapshot f.
rate_linear_growth(f[, z, unit])	Calculate the linear growth rate b'(a), normalized to 1 at z=0, for the cosmology of snapshot f.
redshift(f, time)	Calculate the redshift given a snapshot and a time since Big Bang in Gyr.
rho_M(f[, z, unit])	Calculate the matter density of the universe in snapshot f.
rho_crit(f[, z, unit])	Calculate the critical density of the universe in the snapshot f.
tau(f[, z, unit])	Calculate the conformal age of the universe in the snapshot f by integrating the conformal Friedmann equation.