Left: the contour of constant PF = 0.04 (solid line) for the case r_O = 15 km, d = 150 pc, T_O = 11 eV, r_X = 1 km, and M = 1.4   M_⊙. The dashed line shows the analytical result for point-like caps (see text for details). Pulse profiles are class I according to the classification of Beloborodov (2002); i.e., they do not exhibit flat intervals, only when the contour is below the straight line. Right: same for M = 1.8   M_⊙.