Bases: astropy.cosmology.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: .
This form is not recommended for z > 1.
Parameters: | H0 : float or Quantity
Om0 : float
Ode0 : float
w0 : float, optional
wz : float, optional
Tcmb0 : float or scalar Quantity, optional
Neff : float, optional
m_nu : Quantity, optional
Ob0 : float or None, optional
name : str, optional
|
---|
Examples
>>> from astropy.cosmology import w0wzCDM
>>> cosmo = w0wzCDM(H0=70, Om0=0.3, Ode0=0.7, w0=-0.9, wz=0.2)
The comoving distance in Mpc at redshift z:
>>> z = 0.5
>>> 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
Dark energy equation of state at z=0
Derivative of the dark energy equation of state w.r.t. z
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 , and in this case is given by
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 , where is the pressure at redshift z and is the density at redshift z, both in units where c=1. Here this is given by .