Download or read book X-ray Timing of Young Pulsars written by Robert Archibald and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Pulsars are the rotating compact remnants of exploded massive stars. The region surrounding the neutron star, known as the magnetosphere, has properties which are determined by the magnetic ield of the star. In this thesis, I present several observational results involving rotation-powered radio pulsars and magnetars which indicate that pulsar magnetospheres have a more complex structure than a simple dipole, and that the magnetosphere can have a strong efect on all the observed properties of neutron stars. One way to probe the pulsar magnetosphere is through the measurement of braking indices. A braking index quantifies the dependence of the torque on the spin frequency. In Chapter 4 I present a long-term timing study of the rotation-powered pulsar PSR J1846−0258, where we show that the change in braking index reported in this source is long-lived. The most plausible explanation for this changed braking index appears to be due to a change in magnetospheric configuration. In Chapter 5, I present the measurement of a new braking index for the rotation-powered pulsar PSR J1640−4631 of n= 3.15 ± 0.03 - the first measured braking index higher than the canonical three of a magnetic dipole. This result demonstratesthat other physical mechanisms, such as mass or magnetic quadrupole moments most likely need to be taken into account to describe pulsar spin-down & energetics.Another way to probe the magnetospheres of pulsars is by studying the extreme variability seen in the magnetar class. In Chapter 6 I present two years of flux and spin evolution monitoring of the magnetar 1E 1048.1−5937 following an outburst. By comparing to previous outbursts from the source, we show that this pattern of behaviour repeats itself with a quasi-period of ∼1800 days. This behaviour, when compared to similar less extreme events seen in rotation-powered pulsars, appears to implicate processes in the stellar magnetosphere. In Chapter 7, I present the results of monitoring the magnetar 4U 0142+61 over two outbursts, including one with a net spin-down timing event, and compare this timing event to previous such events in other pulsars with high magnetic fields anddiscuss net spin-down glitches now seen in several young, high-B pulsars. The observations that these spin-down events occur in only high-B sources strongly implicates the influence of a large magnetic field in spin-down events and, coupled with the radiatively loud nature of the plurality of spin-down events, suggests an origin in the magnetosphere of the star. In Chapter 8 I present observations of a magnetar-like outburst from the high-magnetic-field pulsar PSR J1119−6127, providing an unambiguous connection between the radio pulsar and magnetar populations.Finally, in Chapter 9, I put these new results in context with recent advances in neutron-star astrophysics, and speculate on avenues for future advancement in the field." --