dark matter halo, while the second line encompasses the contribution from substructures. In particular, $\rho_{\rm m}$ indicates the present day mean matter density in the Universe, and for the function $g(y)$, as alluded to above, we assume the NFW prescription, i.e. $$\label{eq:nfw}
g(y)=\frac{1}{x\left(1+x\right)^2}.$$ The normalization parameter $\rho^\prime$ and the scale radius $a$ can be expressed, for a given profile, as functions of the virial mass $M_{\rm vir}$ and of the virial concentration parameter $c_{\rm vir}$ (by “virial” we mean assuming an overdensity $\Delta_{\rm vir}\simeq343$, see the discussion in [@Colafrancesco:2005ji]). Following [@Colafrancesco:2005ji], we take here for the Coma cluster a virial mass $M_{\rm vir}\simeq 0.9\times 10^{15}M_\odot h^{-1}$ and a concentration $c_{\rm vir}\simeq10$. The distance to Coma is set to 95 Mpc [@Colafrancesco:2005ji]. Further, in Eq. (\[eq:npair\]) above we defined a reference substructure normalization parameter \_s. Finally, the substructure model is specified by the two parameters $f_s$ and $\Delta^2$. The first stands for the ratio of the total mass in subhalos over the total virial mass, \_[M\_[cut]{}]{}\^[M\_[vir]{}]{}[d]{}M\_s M\_s=f\_sM\_[vir]{}, where ${{\rm d}n}/{{\rm d}M_s}$ indicates the sub-halo mass function, and $M_{\rm cut}$ the small scale cut off mass in the matter power spectrum [@Profumo:2006bv; @othersubs]. The second term, $\Delta^2$, indicates the weighed enhancement in 