title   
  

A natural limit on the observable periods of anomalous x-ray pulsars and soft gamma-ray repeaters

Ertan, Ünal and Çalışkan, Şirin and Ekşi, Kazım Yavuz and Erkut, Mehmet Hakan and Alpar, M. Ali (2011) A natural limit on the observable periods of anomalous x-ray pulsars and soft gamma-ray repeaters. In: Astrophysics of Neutron Stars 2010: A Conference in Honor of M. Ali Alpar, Çeşme, Izmir

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Official URL: http://dx.doi.org/10.1063/1.3629506

Abstract

We investigate the dependence of the evolution of neutron stars with fallback disks on the strength of the magnetic dipole field of the star. Using the same model as employed by Ertan et al. (2009), we obtain model curves for different dipole fields showing that the neutron stars with magnetic dipole fields greater than ∼ 1013 G on the surface of the star are not likely to become anomalous X‐ray pulsars (AXPs) and soft gamma‐ray repeaters (SGRs). Other sources with conventional dipole fields evolve into the AXP phase if their disk can penetrate the light cylinder. The upper limits to the observed periods of AXP and SGRs could be understood if the disk becomes inactive below a low temperature around 100 K. We summarize our present and earlier results indicated by the evolutionary model curves of these sources with an emphasis on the importance of the minimum disk temperature and the X‐ray irradiation in the long‐term evolution of AXPs and SGRs with fallback disks.

Item Type:Papers in Conference Proceedings
Uncontrolled Keywords:pulsars: individual (AXPs) – stars:neutron – X-rays, accretion, accretion disks
Subjects:Q Science > QB Astronomy
Q Science > QC Physics
ID Code:17696
Deposited By:Ünal Ertan
Deposited On:05 Jan 2012 21:53
Last Modified:05 Jan 2012 21:59

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