| GEOPHYSICS, ASTRONOMY, AND ASTROPHYSICS |
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Glitch Crisis or Not: a Microscopic Study |
| LI Ang1,2** |
1Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen 361005
2State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190
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| Cite this article: |
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LI Ang 2015 Chin. Phys. Lett. 32 079701 |
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Abstract The problem of glitch crisis has been a great deal of debate recently. It might challenge the standard two-component model, where glitches are thought to be triggered by the sudden unpinning of superfluid vortices in the neutron-star crust. It says that due to crustal entrainment the amount of superfluid in the crust cannot explain the changes in angular momentum required to account for the glitches. However, the argument of this crisis is based on the assumption that the core superfluid is completely coupled to the crust when a glitch happens. The fraction of the coupled core part is actually a quite uncertain problem so far. In this work, we take three possible values for the fraction of the coupled core part and study in detail the crisis problem for a 1.4 M? canonical star, based on a microscopic equation of state for the neutron star's core using the Brueckner–Hartree–Fock approach. For this purpose, two requisite parameters are chosen as follows: the core-crust transition pressure is in the range of Pt=0.2–0.65 MeV/fm3, and the fractional crust radius ΔR/R=0.082 based on experiments. To account for the possibility of a heavier star, a larger value of ΔR/R=0.15 is also chosen for comparison. Then we take the crustal entrainment into account, and evaluate the predictions for the fractional moment of inertia at various conditions. The results show that there is commonly no such glitch crisis, as long as one considers only a small fraction of the core neutron superfluid will contribute to the charged component of the star. Only if the core-crust transition pressure is determined to be a low value, the crisis problem may appear for complete core-crust coupling. This is consistent with a recent study in a phenomenological model.
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Received: 08 January 2015
Published: 30 July 2015
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