Pebble column density Σ_p, integrated over the vertical dimension and averaged over the azimuthal dimension of the simulation box, as a function of radial location x and simulation time t for the simulation with the largest box size, run_0.8_320. Locations at which sink particles emerge are indicated with white dots. Though every pebble cluster forms in one of the filaments, they migrate up to the distance to one of the adjacent filaments. All sink particles emerge as soon as their formation is initiated at t = 35 P_K, and they emerge nearly evenly distributed among the entire radial extent of the box owing to the radial migration of the pebble clusters.