scale, a binary source of mass $M$ in the local universe has an identical waveform (but with different amplitude) to a binary at redshift $z$ with mass $M/(1+z)$; see, e.g., [@1998PhRvD..57.4535F]. Eq. (\[SNR\]), together with the fact that gravitational amplitudes scale inversely with the luminosity distance $D_L(z)$, implies that the horizon redshift $z_{\rm h}$ (i.e., the redshift at which an optimally located and oriented binary would have SNR $\rho_{\rm thr}=8$) can be found via the simple scaling \[DLhor\] D\_h (z\_[h]{}) = D\_L(z) , where $\rho$ is the SNR at any redshift $z$, or luminosity distance $D_L(z)$. Note that the right-hand side depends only on $z$, $M_z$ and $q$. Therefore one can easily turn an SNR calculation at fixed $z$ (cf. Fig. \[fig:Ingredients:SNRContours\]) into a plot of the horizon luminosity distance $D_h$ (or equivalently of the horizon redshift $z_h$) such as Fig. \[fig:Ingredients:Dhorizon\].

[StarTrack]{} produces large catalogs of DCOs with intrinsic parameters $(M,q)$, with each of these binaries merging at a different redshift. Any of these representative DCOs is potentially detectable (depending on precise sky location and binary orientation) when $z<z_{\rm h}$. Determining detectability therefore amounts to a simple interpolation of two-dimensional grids similar to those plotted in Fig. \[fig:Ingredients:Dhorizon\]. These 