The spin evolution of accreting and radio pulsars in binary systems

Pulsars were first\ndiscovered in 1967 and since then the population has grown and expanded over\nseveral wavelengths. In this thesis three different X-ray pulsars and three\nblack widow radio pulsars and their evolution has been examined. The pulsars in\nthis work all show variability that was not expected of their type of sources,\ne.g. the pulsar 2A 1822-371 is found to have an orbital period that is\nexpanding over time more than what is expected. We suggest this to be due to\nthe pulsar being a super Eddington source. Another part of the thesis uncovers\nthat the magnetic field may have a significant influence in the behavior of the\npulsars. Low magnetic field pulsars often show a correlation between their\npulse phase and their flux, whereas we find that this correlation is not\npresent in high magnetic field pulsars. This could mean that the hot spot,\nwhere the pulsations origin, is not moving in high magnetic field pulsars but\ncould be moving in low magnetic field pulsars. The first black widow pulsars\ndiscovered had unstable timing solutions, whereas the black widow pulsars in\nthis work all have stable timing solutions, and we look into possible\nexplanations to this difference.