CCF signal of KELT-20b. The first row refers to night 1 and the second row to night 2. Left panels: 2D tomography of the CCF residuals maps. The dashed lines bracket the expected planetary signal position. Central panels: K_p-∆V_sys maps. The green dotted lines mark the theoretical planetary position. Right panels: planetary emission signal averaged at the theoretical K_p. The magenta line represents the Gaussian fit to the data.