{
  "id": "1605.01753",
  "version": "v1",
  "published": "2016-05-05T20:52:24.000Z",
  "updated": "2016-05-05T20:52:24.000Z",
  "title": "Phase-Resolved Spectroscopy of Type B Quasi-Periodic Oscillations in GX 339-4",
  "authors": [
    "Abigail L. Stevens",
    "Phil Uttley"
  ],
  "comment": "Accepted for publication in MNRAS. 17 pages, 12 figures",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "We present a new spectral-timing technique for phase-resolved spectroscopy and apply it to the low-frequency Type B quasi-periodic oscillation (QPO) from the black hole X-ray binary GX 339-4. We show that on the QPO time-scale the spectrum changes not only in normalisation, but also in spectral shape. Using several different spectral models which parameterise the blackbody and power-law components seen in the time-averaged spectrum, we find that both components are required to vary, although the fractional rms amplitude of blackbody emission is small, ~1.4 per cent compared to ~25 per cent for the power-law emission. However the blackbody variation leads the power-law variation by ~0.3 in relative phase (~110 degrees), giving a significant break in the Fourier lag-energy spectrum that our phase-resolved spectral models are able to reproduce. Our results support a geometric interpretation for the QPO variations where the blackbody variation and its phase relation to the power-law are explained by quasi-periodic heating of the approaching and receding sides of the disk by a precessing Comptonising region. The small amplitude of blackbody variations suggests that the Comptonising region producing the QPO has a relatively large scale-height, and may be linked to the base of the jet, as has previously been suggested to explain the binary orbit inclination-dependence of Type B QPO amplitudes.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-05-05T20:52:24.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "quasi-periodic oscillation",
      "phase-resolved spectroscopy",
      "blackbody variation",
      "black hole x-ray binary gx",
      "spectral models"
    ],
    "publication": {
      "doi": "10.1093/mnras/stw1093"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 17,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1456114
    }
  }
}