Pulse profiles of 4U 0115 + 63 during observation (a) in different energy ranges. Data were collected with the MECS (2–8.5 keV), the HPGSPC (8.5–24 keV) and the PDS (24–90 keV). The phase-energy matrices of the three instruments were arbitrarily shifted by a few energy bins (maximum 3) to take their timing systematics into account and achieve an optimal alignment in their common energy ranges (8–11 keV for the MECS and HPGSPC, 20–25 keV for the HPGSPC and the PDS ).