Gravitational perturbation of the midplane gas density from a 50 M_E-planet embedded in a protoplanetary disc. Displayed is a full annulus (θ = 2π-wide in azimuth) of the protoplanetary disc around the planet located at normalized radius r = 1. The resulting pressure perturbation halts the radial migration of pebbles and thus the solid accretion onto the core. The overdensities at radius r = 0.85 and r = 1.2 correspond to the regions with super-Keplerian rotation, that are highlighted in Fig. 3. A Rossby vortex, here centred at (θ = 3.8,r = 1.2) has formed outside the orbit of the planet.