Analysis of the physical properties of different types of neutron stars

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2005

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Taşkın, Mustafa Özgür

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This thesis is composed of three published articles. Each chapter is devoted to an article. In the first part the origin of some of the single radio pulsars with relatively low magnetic fields (B < 1e12 G) and with characteristic ages (tau) less than 1e7 years is questioned. We proposed that such pulsars might occur as a result of the disruption of high-mass X-ray binary systems after a second supernova explosion. In these binaries, mass accretion on to the surface of X-ray pulsars may lead to the decrease in the magnetic field from its value at birth (B similar to 1e12 ا 1e13 G) down to B < 1e12 G similar to the processes in low-mass X-ray binaries. In the second part we put together many observational data of SGRs and AXPs and analyzed them with the main purpose of the removal of contradiction between the real age (t) of these objects and their characteristic times of period change (tau). SGRs and AXPs are neutron stars that undergo star-quakes. Magnetic activity increases from time to time. We suggest that as a result of these processes plasma is ejected from the NS and propeller mechanism starts to work. Due to propeller effect dP/dt increases, tau decreases. Indeed, high dP/dt values are observed in SGRs and in half of the AXPs. Then, for a long time NS looses its activity, its dP/dt decreases, tau increases and rapid cooling begins. It seems that there is a possible transition between each NS stage (AXP,SGR,dim). This transient cycle may be repeated once or several times until the spin period of the neutron star becomes P > 10 - 12 s. Observational data and mainly the data of AXP 1E 1048-5937 and DRQNS RX J1308.8+2127 support this idea. In the third part dependence of the X-ray luminosity (Lx) of young single pulsars, due to ejection of relativistic particles, on electric field intensity, rate of rotational energy loss (dE/dt), magnetic field, period and some

Subject Keywords

Astrophysics.

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http://etd.lib.metu.edu.tr/upload/12606665/index.pdf
https://hdl.handle.net/11511/15735

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Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

M. Ö. Taşkın, “Analysis of the physical properties of different types of neutron stars,” Ph.D. - Doctoral Program, Middle East Technical University, 2005.