Wei Chen

Chinese Academy of Sciences, Peping, Beijing, China

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Publications (3)5.99 Total impact

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    ABSTRACT: The high mass X-ray binary 4U 1901+03 was reported to have the pulse profile evolving with the X-ray luminosity and energy during its outburst in February-July 2003: the pulse peak changed from double to single along with the decreasing luminosity. We have carried out a detailed analysis on the contemporary phase-resolved energy spectrum of 4U 1901+03 as observed by Rossi X-ray Timing Explorer (RXTE). We find that, both the continuum and the pulse spectra are phase dependent. The optical depth derived from the pulse spectrum is in general larger than that from the continuum. Fe Ka emission line is only detected in the spectrum of the continuum and is missing in the pulse spectrum. This suggests an origin of Fe emission from the accretion disk but not the surface of the neutron star.
    Full-text · Article · Nov 2009 · The Astrophysical Journal
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    ABSTRACT: After a silence of some 32 years, the high-mass X-ray binary (HMXB) 4U1901+03 produced an outburst in Feb. 2003. With the observed data of RXTE (Rossi X-ray Timing Explorer) over a 5 month duration, we have made a systematic study of the pulse profile of this source, and obtained its time evolution and its correlation with the photon energy. It is found that the variations of the pulse profile and the pulse fraction with the accretion rate of the binary system exhibit a stepwise evolution, and that the pulse fraction reaches its peak at energies under ten KeV. The complex variation of the pulse profile indicates that the pulse profile can not be explained by a single geometrical or physical model, rather, it must be related with both the viewing angle and the radiation mechanism. The observed features are here discussed in terms of the standard radiation model of pulsars.
    No preview · Article · Jul 2008 · Chinese Astronomy and Astrophysics
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    ABSTRACT: We have carried out detailed analysis on the black hole candidate (BHC) X- ray transient Swift J1753.5-0127 observed by the Rossi X-Ray Timing Explorer (RXTE) during its outburst in 2005 {2006. The spectral analysis shows that the emissions are dominated by the hard X-rays, thus revealing the low/hard state of the source during the outburst. The peak luminosity is found lower than the typical value of balancing the mass flow and evaporation of the inner edge of disk (Meyer-Hofmeister 2004). As a result, the disk is prevented from extending inward to produce strong soft X-rays, corresponding to the so-called high/soft state. These are the typical characteristics for a small subset of BHCs, i.e. those soft X-ray transients stay at the low/hard state during the outburst. In most observational time, the QPO frequencies are found to vary roughly linearly with the fluxes and the spectral indices, while the deviation from this relationship at the peak luminosity might provide the first observational evidence of a partially evaporated inner edge of the accretion disk. The anti-correlation between the QPO frequency and spectral color suggests that the global disk oscillation model proposed by Titarchuk & Osherovich (2000) is not likely at work.
    Full-text · Article · Feb 2007

Publication Stats

5 Citations
5.99 Total Impact Points


  • 2008-2009
    • Chinese Academy of Sciences
      • • Institute of High Energy Physics
      • • Key Laboratory of Particle Astrophysics
      Peping, Beijing, China
  • 2007
    • Institute of physics china
      Peping, Beijing, China