Bases: astropy.cosmology.core.FLRW
FLRW cosmology with a variable dark energy equation of state and curvature.
The equation for the dark energy equation of state uses the simple form: w(z) = w_0 + w_z z.
This form is not recommended for z > 1.
Examples
>>> from astro.cosmology import wawzCDM
>>> cosmo = wawzCDM(H0=70, Om0=0.3, Ode0=0.7, w0=-0.9, wz=0.2)
The comoving distance in Mpc at redshift z:
>>> dc = cosmo.comoving_distance(z)
Attributes Summary
w0 | Dark energy equation of state at z=0 |
wz | Derivative of the dark energy equation of state w.r.t. |
Methods Summary
de_density_scale(z) | Evaluates the redshift dependence of the dark energy density. |
w(z) | Returns dark energy equation of state at redshift z. |
Attributes Documentation
Methods Documentation
Evaluates the redshift dependence of the dark energy density.
Parameters : | z : array_like
|
---|---|
Returns : | I : ndarray, or float if input scalar
|
Notes
The scaling factor, I, is defined by \rho(z) = \rho_0 I, and in this case is given by
I = \left(1 + z\right)^{3 \left(1 + w_0 - w_z\right)} \exp \left(-3 w_z z\right)
Returns dark energy equation of state at redshift z.
Parameters : | z : array_like
|
---|---|
Returns : | w : ndarray, or float if input scalar
|
Notes
The dark energy equation of state is defined as w(z) = P(z)/\rho(z), where P(z) is the pressure at redshift z and \rho(z) is the density at redshift z, both in units where c=1. Here this is given by w(z) = w_0 + w_z z.