nbodykit.cosmology.power.transfers¶

Classes

`CLASS`(cosmo, redshift)	The linear matter transfer function using the CLASS Boltzmann code.
`EisensteinHu`(cosmo, redshift)	The linear matter transfer function using the Eisenstein & Hu (1998) fitting formula with BAO wiggles.
`NoWiggleEisensteinHu`(cosmo, redshift)	Linear power spectrum using the Eisenstein & Hu (1998) fitting formula without BAO wiggles.

class nbodykit.cosmology.power.transfers.CLASS(cosmo, redshift)[source]¶

The linear matter transfer function using the CLASS Boltzmann code.

Parameters

cosmo (Cosmology) – the cosmology instance
redshift (float) – the redshift of the power spectrum

Methods

__call__(k)

Return the CLASS linear transfer function at redshift.

__call__(k)[source]¶

Return the CLASS linear transfer function at redshift. This computes the transfer function from the CLASS linear power spectrum using:

\[T(k) = \left [ P_L(k) / k^n_s \right]^{1/2}.\]

We normalize the transfer function \(T(k)\) to unity as \(k \rightarrow 0\) at \(z=0\).

Parameters: k (float, array_like) – the wavenumbers in units of \(h \mathrm{Mpc}^{-1}\)
Returns: Tk – the transfer function evaluated at k, normalized to unity on large scales
Return type: float, array_like

class nbodykit.cosmology.power.transfers.EisensteinHu(cosmo, redshift)[source]¶

The linear matter transfer function using the Eisenstein & Hu (1998) fitting formula with BAO wiggles.

Parameters

cosmo (Cosmology) – the cosmology instance
redshift (float) – the redshift of the power spectrum

References

Eisenstein & Hu, “Baryonic Features in the Matter Transfer Function”, 1998

Methods

__call__(k)

Return the Eisenstein-Hu transfer function with BAO wiggles.

__call__(k)[source]¶

Return the Eisenstein-Hu transfer function with BAO wiggles.

This is normalized to unity as \(k \rightarrow 0\) at \(z=0\). The redshift scaling is provided by the Cosmology.scale_independent_growth_factor() function.

Parameters: k (float, array_like) – the wavenumbers in units of \(h \mathrm{Mpc}^{-1}\)
Returns: Tk – the transfer function evaluated at k, normalized to unity on large scales
Return type: float, array_like

class nbodykit.cosmology.power.transfers.NoWiggleEisensteinHu(cosmo, redshift)[source]¶

Linear power spectrum using the Eisenstein & Hu (1998) fitting formula without BAO wiggles.

Parameters

cosmo (Cosmology) – the cosmology instance
redshift (float) – the redshift of the power spectrum

References

Eisenstein & Hu, “Baryonic Features in the Matter Transfer Function”, 1998

Methods

__call__(k)

Return the Eisenstein-Hu transfer function without BAO wiggles.

__call__(k)[source]¶

Return the Eisenstein-Hu transfer function without BAO wiggles.

This is normalized to unity as \(k \rightarrow 0\) at \(z=0\). The redshift scaling is provided by the scale_independent_growth_factor() function.

Parameters: k (float, array_like) – the wavenumbers in units of \(h \mathrm{Mpc}^{-1}\)
Returns: Tk – the transfer function evaluated at k, normalized to unity on large scales
Return type: float, array_like