Modelling pulsar glitches with realistic pinning forces: a hydrodynamical approach


  • B. Haskell,

    Corresponding author
    1. School of Mathematics, University of Southampton, Southampton SO17 1BJ
    2. Astronomical Institute ‘Anton Pannekoek’, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, the Netherlands
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  • P. M. Pizzochero,

    1. Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy
    2. Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Via Celoria 16, 20133 Milano, Italy
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  • T. Sidery

    1. FENS, Sabanci University, Orhanli, 34956 Istanbul, Turkey
    2. School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT
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Although pulsars are some of the most stable clocks in the Universe, many of them are observed to ‘glitch’, i.e. to suddenly increase their spin frequency inline image with fractional increases that range from inline image to inline image. In this paper, we focus on the ‘giant’ glitches, i.e. glitches with fractional increases in the spin rate of the order of inline image, that are observed in a subclass of pulsars including the Vela. We show that giant glitches can be modelled with a two-fluid hydrodynamical approach. The model is based on the formalism for superfluid neutron stars of Andersson & Comer and on the realistic pinning forces of Grill & Pizzochero. We show that all stages of Vela glitches, from the rise to the post-glitch relaxation, can be reproduced with a set of physically reasonable parameters and that the sizes and waiting times between giant glitches in other pulsars are also consistent with our model.