{
  "id": "1605.06356",
  "version": "v1",
  "published": "2016-05-20T13:51:16.000Z",
  "updated": "2016-05-20T13:51:16.000Z",
  "title": "XMM-Newton discovery of mHz quasi-periodic oscillations in the high mass X-ray binary IGRJ19140+0951",
  "authors": [
    "L. Sidoli",
    "P. Esposito",
    "S. E. Motta",
    "G. L. Israel",
    "G. A. Rodriguez Castillo"
  ],
  "comment": "11 pages, 8 figures. Accepted for publication in MNRAS on 2016, May 20 (submitted on 2016, April 22)",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "We report on the discovery of mHz quasi-periodic oscillations (QPOs) from the high mass X-ray binary (HMXB) IGRJ19140+0951, during a 40 ks XMM-Newton observation performed in 201 5, which caught the source in its faintest state ever observed. At the start of the observation, IGRJ19140+0951 was at a low flux of 2$\\times$10$^{-12}$~erg~cm$^{-2}$~s$^{-1}$ ( 2-10 keV; L$_{\\rm X}$=3$\\times$10$^{33}$~erg~s$^{-1}$ at 3.6 kpc), then its emission rised reaching a flux 10 times higher, in a flare-like activity. The investigation of the pow er spectrum reveals the presence of QPOs, detected only in the second part of the observation, with a strong peak at a frequency of 1.46$\\pm{0.07}$~mHz, together with higher harm onics. The X-ray spectrum is highly absorbed (N$_{\\rm H}$=$10^{23}$~cm$^{-2}$), well fitted by a power-law with a photon index in the range 1.2-1.8. The re-analysis of a Chandra archival observation shows a modulation at 0.17+/-0.05mHz, very likely the neutron star spin period (although a QPO cannot be excluded). We discuss the origin of the 1.46 mHz QPO in the framework of both disc-fed and wind-fed HMXBs, favouring the quasi-spherical accretion scenario. The low flux observed by XMM-Newton leads to about three orders of magnit ude the source dynamic range, overlapping with the one observed from Supergiant Fast X-ray Transients (SFXTs). However, since its duty cycle is not as low as in SFXTs, IGRJ19140 +0951 is an intermediate system between persistent supergiant HMXBs and SFXTs, suggesting a smooth transition between these two sub-classes.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-05-20T13:51:16.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "high mass x-ray binary",
      "mhz quasi-periodic oscillations",
      "xmm-newton discovery",
      "low flux",
      "neutron star spin period"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 11,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1463255
    }
  }
}