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This objects implements the Bardeen, Bond, Kaiser and Szalay (BBKS) transfer function. See appendix G from Bardeen et al. (1986) [ads].
All three available transfer functions basically follow the same pattern, \begin{equation*} T(k) = \frac{\ln \left( 1 + 2.34q \right)}{2.34 q} \left[1 + 3.89 q + (16.1 q)^2 + (5.46 q)^3 + (6.71 q)^4 \right]^{-1/4} \, . \end{equation*} The difference is the parameter $q$:
Cold Dark Matter without baryons (NC_TRANSFER_FUNC_BBKS_TYPE_NOBARYONS): $$ q = k \frac{(T_{\mathrm{cmb}}/2.7)^2}{\Omega_m h^2} \, .$$
Cold Dark Matter with baryons (NC_TRANSFER_FUNC_BBKS_TYPE_BARYONS): $$ q = k \frac{(T_{\mathrm{cmb}}/2.7)^2}{\Omega_m h^2} \frac{1}{\exp\left( -\Omega_b - \sqrt{2h} \frac{\Omega_b}{\Omega_m} \right)} $$
Cold Dark Matter with baryons but without the radiation term (NC_TRANSFER_FUNC_BBKS_TYPE_CCL): $$ q = k \frac{1}{\Omega_m h^2} \frac{1}{\exp\left( -\Omega_b - \sqrt{2h} \frac{\Omega_b}{\Omega_m} \right)} $$
Where $T_{\mathrm{cmb}}$ is cosmic microwave background radiation mean temperature today (nc_hicosmo_T_gamma0), $\Omega_m h^2$ is dimensionless total dust density today multiplied by the reduced Hubble constant, $h$, squared (nc_hicosmo_Omega_m0h2), $\Omega_b$ is the dimensionless baryon density today (nc_hicosmo_Omega_b0).
NcTransferFunc *
nc_transfer_func_bbks_new (void);
Creates a new NcTransferFunc of the BBKS type.
void nc_transfer_func_bbks_set_type (NcTransferFuncBBKS *tf_bbks,NcTransferFuncBBKSType bbks_type);
Sets BBKS variant type.
“type” property“type” NcTransferFuncBBKSType
The BBKS transfer function variant type to be applied in NcTransferFunc.
We have three options:
Cold Dark Matter without baryons (NC_TRANSFER_FUNC_BBKS_TYPE_NOBARYONS):
Cold Dark Matter with baryons (NC_TRANSFER_FUNC_BBKS_TYPE_BARYONS):
Cold Dark Matter with baryons but without the radiation term (NC_TRANSFER_FUNC_BBKS_TYPE_CCL):
Owner: NcTransferFuncBBKS
Flags: Read / Write / Construct
Default value: NC_TRANSFER_FUNC_BBKS_TYPE_NOBARYONS