The time lag spectrum of Cir X-1 on its normal branch

  • JinLu Qu
  • Yu Lu
  • GuoQiang Ding
  • Fan Zhang
  • YaJuan Lei
  • ZhiBing Li
Research Papers


In the radiation-hydrodynamics model, the time lag and fractional root-mean-squared (rms) amplitude as a function of emitted photon energy should show a minimum on the normal branch oscillations. This has been seen in the Z-sources Cyg X-2 and GX 5-1. Here, using the observations from the Rossi X-ray Timing Explorer (RXTE), we study the energy dependence of normal branch QPOs in the peculiar Z-source Cir X-1. We discuss the results in the context of radiation-hydrodynamics and the Comptonization model.


Cir X-1 temporal variability QPO time lag 


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Copyright information

© Science China Press and Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • JinLu Qu
    • 1
  • Yu Lu
    • 1
    • 2
  • GuoQiang Ding
    • 3
  • Fan Zhang
    • 1
  • YaJuan Lei
    • 1
  • ZhiBing Li
    • 1
  1. 1.Key Laboratory for Particle Astrophysics, Institute of High Energy PhysicsChinese Academy of SciencesBeijingChina
  2. 2.Graduate University of Chinese Academy of SciencesBeijingChina
  3. 3.Urumqi ObservatoryNAOCUrumqiChina

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