{
  "id": "1407.6733",
  "version": "v3",
  "published": "2014-07-24T20:50:14.000Z",
  "updated": "2015-01-29T08:28:15.000Z",
  "title": "Period clustering of the anomalous X-ray pulsars",
  "authors": [
    "G. S. Bisnovatyi-Kogan",
    "N. R. Ikhsanov"
  ],
  "comment": "accepted for publication in Astronomy Reports v. 59, No. 5 (2015)",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "In this paper we address the question of why the observed periods of the Anomalous X-ray Pulsars (AXPs) and Soft Gamma-ray Repeaters (SGRs) are clustered in the range 2-12 s. We explore a possibility to answer this question assuming that AXPs and SGRs are the descendants of High Mass X-ray Binaries (HMXBs) which have been disintegrated in the core-collapse supernova explosion. The spin period of neutron stars in HMXBs evolves towards the equilibrium period, averaging around a few seconds. After the explosion of its massive companion, the neutron star turns out to be embedded into a dense gaseous envelope, the accretion from which leads to the formation of a residual magnetically-levitating (ML) disk. We show that the expected mass of a disk in this case is 10^-7 - 10^-8 M_sun which is sufficient to maintain the process of accretion at the rate 10^14 - 10^15 g/s over a time span of a few thousand years. During this period the star manifests itself as an isolated X-ray pulsar with a number of parameters resembling those of AXPs and SGRs. Period clustering of such pulsars can be provided if the lifetime of the residual disk does not exceed the spin-down timescale of the neutron star.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2014-08-12T13:06:16.000Z",
      "abstract": "In this paper we address the question of why the observed periods of the Anomalous X-ray Pulsars (AXPs) and Soft Gamma-ray Repeaters (SGRs) are clustered in the range 2-12s. We explore a possibility to answer this question assuming that AXPs and SGRs are the descendants of High Mass X-ray Binaries (HMXBs) which have been disintegrated in the core-collapse supernova explosion. The spin period of neutron stars in HMXBs evolves towards the equilibrium period, P_eq. For a wide range of relevant accretion parameters, its value falls in the interval of observed periods of AXPs and SGRs. After the explosion of its massive companion, the neutron star turns out to be embedded into a dense gaseous envelope, the accretion from which leads to the formation of a residual magnetically levitating (ML) disk. We show that the expected mass of a disk in this case is 10^-7 - 10^-8 M_sun which is sufficient to maintain the process of accretion at the rate 10^14 - 10^15 g/s over a time span of a few thousand years. During this period the star manifests itself as an isolated X-ray pulsar with parameters close to those observed from AXPs and SGRs. Period clustering of such pulsars can be provided if the lifetime of the residual disk does not exceed the spin-down timescale of the neutron star.",
      "comment": "submitted to Astronomy Reports",
      "journal": null,
      "doi": null
    },
    {
      "version": "v3",
      "updated": "2015-01-29T08:28:15.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "anomalous x-ray pulsars",
      "period clustering",
      "high mass x-ray binaries",
      "core-collapse supernova explosion",
      "neutron star turns"
    ],
    "publication": {
      "doi": "10.1134/S1063772915050017",
      "journal": "Astronomy Reports",
      "year": 2015,
      "month": "Jun",
      "volume": 59,
      "number": 6,
      "pages": 503
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1308072,
      "adsabs": "2015ARep...59..503B"
    }
  }
}