{
  "id": "1109.1040",
  "version": "v1",
  "published": "2011-09-06T01:51:51.000Z",
  "updated": "2011-09-06T01:51:51.000Z",
  "title": "Quadrupole moment of a magnetically confined mountain on an accreting neutron star: effect of the equation of state",
  "authors": [
    "M. Priymak",
    "A. Melatos",
    "D. J. B. Payne"
  ],
  "comment": "20 pages, 15 figures, to be published in MNRAS",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "Magnetically confined mountains on accreting neutron stars are promising sources of continuous-wave gravitational radiation and are currently the targets of directed searches with long-baseline detectors like the Laser Interferometer Gravitational Wave Observatory (LIGO). In this paper, previous ideal-magnetohydrodynamic models of isothermal mountains are generalized to a range of physically motivated, adiabatic equations of state. It is found that the mass ellipticity drops substantially, from \\epsilon ~ 3e-4 (isothermal) to \\epsilon ~ 9e-7 (non-relativistic degenerate neutrons), 6e-8 (relativistic degenerate electrons) and 1e-8 (non-relativistic degenerate electrons) (assuming a magnetic field of 3e12 G at birth). The characteristic mass M_{c} at which the magnetic dipole moment halves from its initial value is also modified, from M_{c}/M_{\\sun} ~ 5e-4 (isothermal) to M_{c}/M_{\\sun} ~ 2e-6, 1e-7, and 3e-8 for the above three equations of state, respectively. Similar results are obtained for a realistic, piecewise-polytropic nuclear equation of state. The adiabatic models are consistent with current LIGO upper limits, unlike the isothermal models. Updated estimates of gravitational-wave detectability are made. Monte Carlo simulations of the spin distribution of accreting millisecond pulsars including gravitational-wave stalling agree better with observations for certain adiabatic equations of state, implying that X-ray spin measurements can probe the equation of state when coupled with magnetic mountain models.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2011-09-06T01:51:51.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "accreting neutron star",
      "magnetically confined mountain",
      "quadrupole moment",
      "laser interferometer gravitational wave observatory",
      "current ligo upper limits"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1111/j.1365-2966.2011.19431.x",
      "journal": "Monthly Notices of the Royal Astronomical Society",
      "year": 2011,
      "month": "Nov",
      "volume": 417,
      "number": 4,
      "pages": 2696
    },
    "note": {
      "typesetting": "TeX",
      "pages": 20,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 926563,
      "adsabs": "2011MNRAS.417.2696P"
    }
  }
}