Statistical freeze-out of bright quasars at z ~ 10 in a heavy-seed scenario

We present a minimal phenomenological model for the statistical freeze-out of bright quasars at z > 7 in a heavy-seed scenario. The model is calibrated to the z ~ 7 quasar luminosity function and makes forward predictions for z > 7 without further parameter adjustment. We compute Poisson detection probabilities for the Roman High Latitude Survey and show that multiple detections at z ~ 10 would place the baseline model under severe statistical tension. Submitted to MNRAS (major revision, ref. MN-26-0145-P). ## Keywords quasars, high redshift, black hole seeds, luminosity function, Roman Space Telescope