| dc.description.abstract | In this bachelor thesis I have updated the high-energy "absolute" timing picture of the Crab pulsar by including the Fermi LAT gamma-ray data (> 100 MeV) collected from the start of the Fermi science operations (4-8-2008) until October 2016, and the XMM-Newton EPIC PN data by analysing the bi-yearly Crab timing observations taken in Burst and Timing mode (0.3-12 keV). This bachelor thesis also uses the high-energy "absolute" timing measurements of INTEGRAL IBIS ISGRI (20-300 keV, from the INTEGRAL launch date until October 2016) and RXTE PCA (3-32 keV, from the INTEGRAL launch date until its decommissioning at 5-1-2012). The Jodrell Bank Observatory Crab pulsar monthly ephemerides have served as baseline for all these "absolute" timing measurements. These ephemerides have been reliable in almost all months analysed in this study. There were a small number of cases in which suspected behaviour (outliers) has been discovered. Excluding outliers, the average time shift between the gamma-ray pulse maximum and the radio pulse maximum for Fermi LAT is -111 +/- 4 microseconds. For XMM Newton I found, again excluding outliers, for the EPIC PN operating in Burst mode a time shift -353 +/- 4 microseconds and -271 +/- 4 microseconds, when EPIC PN operates in Timing mode. This apparent discrepancy means that Burst and Timing mode data should not be mixed. INTEGRAL IBIS ISGRI data, excluding outliers, showed a time shift of -248 +/- 2 microseconds, consistent with an earlier measurement (Kuiper et al. (2003)) correcting for an additional ground station delay of 47 microseconds. Finally, for RXTE PCA a value of -297 +/- 3 microseconds has been derived, which is consistent within statistical and systematical margins with previous values, estimated by Rots et al. (2004) and Molkov et al. (2010). Combining the results across the X-ray, hard X-ray, soft gamma-ray and > 100 MeV gamma-ray bands no evidence is found for a linear trend in the time delays, as found by Molkov et al. (2010). | |
