Flatw0waCDM¶

class
astropy.cosmology.
Flatw0waCDM
(H0, Om0, w0=1.0, wa=0.0, Tcmb0=0, Neff=3.04, m_nu=<Quantity 0. eV>, Ob0=None, name=None)[source]¶ Bases:
astropy.cosmology.w0waCDM
FLRW cosmology with a CPL dark energy equation of state and no curvature.
The equation for the dark energy equation of state uses the CPL form as described in Chevallier & Polarski Int. J. Mod. Phys. D10, 213 (2001) and Linder PRL 90, 91301 (2003): \(w(z) = w_0 + w_a (1a) = w_0 + w_a z / (1+z)\).
 Parameters
 H0float or
Quantity
Hubble constant at z = 0. If a float, must be in [km/sec/Mpc]
 Om0float
Omega matter: density of nonrelativistic matter in units of the critical density at z=0.
 w0float, optional
Dark energy equation of state at z=0 (a=1). This is pressure/density for dark energy in units where c=1.
 wafloat, optional
Negative derivative of the dark energy equation of state with respect to the scale factor. A cosmological constant has w0=1.0 and wa=0.0.
 Tcmb0float or scalar
Quantity
, optional Temperature of the CMB z=0. If a float, must be in [K]. Default: 0 [K]. Setting this to zero will turn off both photons and neutrinos (even massive ones).
 Nefffloat, optional
Effective number of Neutrino species. Default 3.04.
 m_nu
Quantity
, optional Mass of each neutrino species. If this is a scalar Quantity, then all neutrino species are assumed to have that mass. Otherwise, the mass of each species. The actual number of neutrino species (and hence the number of elements of m_nu if it is not scalar) must be the floor of Neff. Typically this means you should provide three neutrino masses unless you are considering something like a sterile neutrino.
 Ob0float or None, optional
Omega baryons: density of baryonic matter in units of the critical density at z=0. If this is set to None (the default), any computation that requires its value will raise an exception.
 namestr, optional
Name for this cosmological object.
 H0float or
Examples
>>> from astropy.cosmology import Flatw0waCDM >>> cosmo = Flatw0waCDM(H0=70, Om0=0.3, w0=0.9, wa=0.2)
The comoving distance in Mpc at redshift z:
>>> z = 0.5 >>> dc = cosmo.comoving_distance(z)