Horizontal flow divergences of the considered active regions before their emergence (at T = −0.05) in the normalised coordinates. Black stars indicate the determined positions of the polarities. We note that not for all ARs the frames are available (they were too close to the limb to be considered). All the subplots were saturated at ±0.01, which roughly corresponds to ±0.036 s⁻¹. Green colour indicates a positive horizontal divergence, purple the negative one (a convergence). Over the fields of view, the divergence pattern is dominated by supergranular flows.