X-ray spectral evolution of low-mass X-ray binary GX 349+2 |
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| Authors: | V K Agrawal P Sreekumar |
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| Institution: | Space Astronomy &Instrumentation Division, ISRO Satellite Centre, Bangalore-17, India |
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| Abstract: | We present the results of a systematic investigation of spectral evolution in the Z source GX 349+2, using data obtained during 1998 with the Proportional Counter Array (PCA) on-board the RXTE satellite. The source traced a extended normal branch (NB) and flaring branch (FB) in the colour–colour diagram (CD) and the hardness-intensity diagram (HID) during these observations. The spectra at different positions of the Z-track were best fitted by a model consisting of a disc blackbody and a Comptonized spectrum. A broad (Gaussian) iron line at ～6.7 keV is also required to improve the fit. The spectral parameters showed a systematic and significant variation with the position along the Z-track. The evolution in spectral parameters is discussed in view of the increasing mass accretion rate scenario, proposed to explain the motion of Z sources in the CD and the HID. |
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| Keywords: | accretion accretion discs binaries: close stars: individual: GX 349+2 stars: neutron X-rays: general X-rays: stars |
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