NumCosmoXcorKernelClusterTophat

Implementation of cluster kernel using a top-hat redshift distribution.

This implements a simplified cluster kernel using the thin-z approximation, where all mass-dependent factors are assumed constant within the redshift bin and are absorbed into an overall normalization.

The kernel is given by: \begin{equation} K(z,k) = \Theta(z; z_{\rm lower}, z_{\rm upper}) \sqrt{P(k,z)} \end{equation}

where $\Theta(z; z_{\rm lower}, z_{\rm upper})$ is a normalized top-hat function: \begin{equation} \Theta(z; z_{\rm lower}, z_{\rm upper}) = \begin{cases} \frac{1}{z_{\rm upper} - z_{\rm lower}} & \text{if } z_{\rm lower} \le z \le z_{\rm upper} \ 0 & \text{otherwise} \end{cases} \end{equation}

and $P(k,z)$ is the matter power spectrum.