High-energy emission and temporal properties of magnetars

Official URL: http://risc01.sabanciuniv.edu/record=b1589827 (Table of Contents)

Magnetars have been intriguing sources since their discovery, as they opened new avenues on the formation, evolution and emission mechanisms of the neutron stars. Thanks to the long-term observations of these sources, we are able to investigate many aspects of them. In this thesis, we investigate the high-energy gamma-ray emission properties of one of the brightest magnetars in X-ray band, 4U 0142+61. We searched for persistent and pulsed gamma-ray emission using the data obtained with Fermi/LAT. We did not detect significant high-energy gamma-ray emission from this source. Nevertheless, we could place upper limits to the gamma-ray flux and spectral break energy of the source. Together with the earlier works on soft and hard X-ray emission of 4U 0142+61, these upper limits provide a hint on the spectral shape of the source in a wide energy band. Next, we studied the long-term timing and X-ray properties of two frequently glitching magnetars, 1RXS J170849.0- 400910 and 1E 1841-045, with RXTE/PCA. In the analysis of 1RXS J170849.0- 400910 we identified two significant glitch candidates in two data gaps. The source was radiatively stable during the RXTE observations. In the analysis of 1E 1841- 045, we identified a glitch and an anti-glitch ∼1 yr apart from each other. We found no evidence of radiative variability during both the glitch and anti-glitch events. Finally, we discuss our results in the context of glitch models.