A python package to calculate cosmological distances in a FRW metric.

Description

A package to calculate cosmological distances. The workhorse is a class Cosmo that wraps and the underlying C code. The geometry can be non-flat.

In order to take advantage of the speed of the underlying C code, you should, if at all possible, send numpy arrays to the methods rather than repeatedly call the python methods.

Installation

    python setup.py install --prefix=/some/path

If you want to use UPS to manage your code install with the with_ups command

    python setup.py with_ups install --prefix=/some/path

Class

import cosmology
c=cosmology.Cosmo()

Methods

DH: Return the hubble distance.
Dc: Comoving distance.
Dm: Transverse comoving distance.
Da: Angular diameter distance.
Dl: Luminosity distance.
dV: Volume element.
V:  Volume between two redshifts.
distmod: Distance modulus.
sigmacritinv: Inverse critical density for lensing.

Ez_inverse: Calculate 1/E(z)
Ezinv_integral: Calculate the integral of 1/E(z) from zmin to zmax

flat(): return if universe is flat
omega_m(): value of omega matter
omega_l(): value of omega lambda
omega_k(): value of omega curvature

Examples

import cosmology
c=cosmology.Cosmo()

# comoving distance to z=0.5
c.Dc(0.0, 0.5) 

# angular diameter distance between z=0.5 and z=0.9
c.Da(0.5, 0.9)

# luminosity distance between z=0.2 and a sequence of redshifts
c.Dl(0.2, [0.3, 0.4, 0.5])

# new cosmology
c=cosmology.Cosmo(H0=70.0, omega_m=0.25)

# inverse critical density for lensing, lens at 0.2 and
# source at 0.3
c.sigmacritinv(0.2, 0.3)

Unit Tests

    import cosmology
    cosmology.test()

TODO

• Add equation of state
• Add evolving equation of state.