These are the latest articles published in Chinese Journal of Astronomy and Astrophysics.

• Open/close Exploring the INTEGRAL Sources in Search for New Microquasars

  M Ribó et al 2005 Chin. J. Astron. Astrophys. 5 1 Tag this article

  Article References Full text PDF (343 KB)

  Here we present a search for new microquasars among the sources detected with the INTEGRAL satellite (IGR sources). We focus on radio emitting IGR sources and report the discovery of two new probable extragalactic sources behind the galactic plane, as well as the detection at higher energies of the ASCA source AX J1639.0-4642, probably a new microquasar in the Galaxy and coincident with a high-energy gamma-ray emitting EGRET source.

• Open/close INTEGRAL Reveals a New Class of Obscured High Mass X-ray Binaries: Focus on IGR J16318–4848

  Sylvain Chat and Philippe Filliatre 2005 Chin. J. Astron. Astrophys. 5 104 Tag this article

  Article References Full text PDF (395 KB)

  The X-ray source IGR J16318-4848 is the first source discovered by INTEGRAL on 2003, January 29, exhibiting a very high column density. On 2003, February, 23–25 we triggered a Target of Opportunity (ToO) program using the EMMI (optical) and SOFI (near-infrared, NIR) instruments on the New Technology Telescope of the European Southern Observatory (NTT/ESO La Silla). We discovered the optical counterpart and confirmed the NIR candidate. NIR spectroscopy revealed a large amount of emission lines, including forbidden iron and P-Cygni profiles. We show that the source is a High Mass X-ray binary (HMXB) at a distance between 0.9 and 6.2 kpc, the mass donor being an early-type star, probably a sgB[e] star, surrounded by a dense and absorbing circumstellar material. This would make the second HMXB with a sgB[e] after CI Cam. Other sources, discovered by INTEGRAL near IGR J16318-4848 in the direction of the Norma arm, present the same characteristics. Such sources may represent a different evolutionary state of X-ray binaries previously undetected with the lower energy space telescopes; if it is so, a new class of strongly absorbed X-ray binaries is being unveiled by INTEGRAL.

• Open/close Microquasars and Gamma-ray Sources

  Gustavo E Romero 2005 Chin. J. Astron. Astrophys. 5 110 Tag this article

  Article References Full text PDF (194 KB)

  Microquasars are X-ray binary systems with non-thermal radio emission originated in jet-like features. They are attractive sites for gamma-ray production, since relativistic particles in the jet should traverse locally strong both photon and matter fields. In this review we discuss whether some of the unidentified gamma-ray sources detected by the EGRET instrument of the Compton Gamma-Ray Observatory might be associated with microquasars. Relevant models for gamma-ray emission in such binaries are described and prospects for the detection of microquasars with instruments of new generation are briefly evaluated.

• Open/close Shot Timescales in Accreting Black Hole Binaries: ω Spectrum and its Application

  Hua Feng et al 2005 Chin. J. Astron. Astrophys. 5 13 Tag this article

  Article References Full text PDF (211 KB)

  We proposed a new statistic ω spectrum which can detect the shot width distribution sensitively. By applying the ω spectrum to X-ray binaries, we can distinguish between neutron stars and black holes from their different shot behaviours at small timescales. The energy dependent analysis for black hole binaries, in particular for Cyg X-1, can help us to reveal dynamical evidence for black hole accretion flows and state transitions. Both narrow and broad iron Kα lines are presented in the ω analysis, affording dynamical evidence for iron lines origin.

• Open/close Microquasars as High-energy Gamma-ray Sources

  Josep M Paredes 2005 Chin. J. Astron. Astrophys. 5 121 Tag this article

  Article References Full text PDF (657 KB)

  Galactic microquasars are certainly one of the most recent additions to the field of high energy astrophysics and have attracted increasing interest over the last decade. However, the high energy part of the spectrum of microquasars is the most poorly known, mainly due the lack of sensitive instrumentation in the past. Microquasars are now primary targets for all of the observatories working in the X-ray and gamma-ray domains. They also appear as the possible counterparts for some of the unidentified sources of high-energy gamma-rays detected by the experiment EGRET on board the satellite COMPTON-GRO. This paper provides a general review of the main observational results obtained up to now as well as a summary of the scenarios for production of high-energy γ-rays at the present moment.