{
  "id": "0911.2618",
  "version": "v1",
  "published": "2009-11-13T14:24:55.000Z",
  "updated": "2009-11-13T14:24:55.000Z",
  "title": "Absolute timing of the Crab pulsar with the INTEGRAL/SPI telescope",
  "authors": [
    "S. Molkov",
    "E. Jourdain",
    "J. P. Roques"
  ],
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "We have investigated the pulse shape evolution of the Crab pulsar emission in the hard X-ray domain of the electromagnetic spectrum. In particular, we have studied the alignment of the Crab pulsar phase profiles measured in the hard X-rays and in other wavebands. To obtain the hard X-ray pulse profiles, we have used six year (2003-2009, with a total exposure of about 4 Ms) of publicly available data of the SPI telescope on-board of the INTEGRAL observatory, folded with the pulsar time solution derived from the Jodrell Bank Crab Pulsar Monthly Ephemeris. We found that the main pulse in the hard X-ray 20-100 keV energy band is leading the radio one by $8.18\\pm0.46$ milliperiods in phase, or $275\\pm15 \\mu s$ in time. Quoted errors represent only statistical uncertainties.Our systematic error is estimated to be $\\sim 40 \\mu s$ and is mainly caused by the radio measurement uncertainties. In hard X-rays, the average distance between the main pulse and interpulse on the phase plane is $0.3989\\pm0.0009$. To compare our findings in hard X-rays with the soft 2-20 keV X-ray band, we have used data of quasi-simultaneous Crab observations with the PCA monitor on-board the Rossi X-Ray Timing Explorer (RXTE) mission. The time lag and the pulses separation values measured in the 3-20 keV band are $0.00933\\pm0.00016$ (corresponding to $310\\pm6 \\mu s$) and $0.40016\\pm0.00028$ parts of the cycle, respectively. While the pulse separation values measured in soft X-rays and hard X-rays agree, the time lags are statistically different. Additional analysis show that the delay between the radio and X-ray signals varies with energy in the 2 - 300 keV energy range. We explain such a behaviour as due to the superposition of two independent components responsible for the Crab pulsed emission in this energy band.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2009-11-13T14:24:55.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "hard x-ray",
      "integral/spi telescope",
      "pulsar phase profiles",
      "absolute timing",
      "separation values"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/708/1/403",
      "journal": "The Astrophysical Journal",
      "year": 2010,
      "month": "Jan",
      "volume": 708,
      "number": 1,
      "pages": 403
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 836881,
      "adsabs": "2010ApJ...708..403M"
    }
  }
}