For our three-dimensional PIXELPOP model, the inferred comoving merger-rate density ﹩{ \mathcal R }({m}_{1},q;z)﹩ (left), ﹩{ \mathcal R }({m}_{1},{\chi }_{{\rm{eff}}};z)﹩ (center), and ﹩{ \mathcal R }(q,{\chi }_{{\rm{eff}}};z)﹩ (right), evaluated at fixed redshifts z = 0.2 (top) and z = 0.8 (bottom). In each figure, the central panel shows the median of the two-dimensional merger-rate posterior, along with 50% and 90% credibility contours of the true underlying population of our simulated catalog; brighter regions indicate a higher inferred merger rate. Similarly, each upper (right-hand) panel shows the rate marginalized over the source parameter on the vertical (horizontal) axis; the dashed line represents the true population, while the solid line and shaded region represent the posterior median and central 90% credible region.