RXTE observations of the strongly absorbed sources IGR J16318-4848 and IGR J16358-4726
RXTE observations of the strongly absorbed sources IGR J16318-4848 and IGR J16358-4726
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强吸收源 IGR J16318-4848 和 IGR J16358-4726 的 RXTE 观测
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发表时间：
2003
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通讯作者：
M. Revnivtsev
中科院分区：
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作者：
M. Revnivtsev
我们分析了两个强吸收源IGR J16318-4848和IGR J16358-4726的RXTE观测。我们能够获得的3-25千电子伏的光谱的来源，考虑到银河系的扩散背景的贡献与RXTE/PCA光谱仪记录的X射线通量。的源的光谱很好地描述了一个幂律减少的光子通量与能量的光子指数为10.1和强的光吸收。由2003年3月14.1日的RXTE观测得到的IGR J16318-4848的光吸收柱密度nHL比XMM天文台在2003年2月10.7日得到的值高得多。这一结果可能表明，源具有可变的吸收，这可能取决于系统的轨道相位。我们指出，INTEGRAL天文台在（l，B）<$（336，0）区发现的三个X射线源（IGR J16318-4848，IGR J16320-4751，IGR J16358-4726）都有很强的内禀光吸收，可能是高质量双星。它们靠近银河系旋臂切线经过的区域，即，年轻的高质量恒星的浓度增加的区域，可以作为这一假设的间接证实。如果我们关于这些源在诺玛旋臂中的位置的假设是正确的，那么我们就可以粗略地估计它们的日心距离：106 -8 kpc。
We analyzed the RXTE observations of two strongly absorbed sources, IGR J16318-4848 and IGR J16358-4726. We were able to obtain the 3–25 keV spectra of the sources by taking into account the contribution of the Galactic diffuse background to the X-ray flux recorded with the RXTE/PCA spectrometer. The spectra of the sources are well described by a power-law decrease of the photon flux with energy with a photon index of ∼1 and strong photoabsorption. The photoabsorption column density nHL for IGR J16318-4848 derived from the RXTE observation on March 14.1, 2003, is shown to be much higher than its value obtained by the XMM observatory on February 10.7, 2003. This result may suggest that the source has variable absorption that may depend on the orbital phase of the system. We point out that all of the three X-ray sources discovered by the INTEGRAL observatory in the region (l,b)∼(336,0) (IGR J16318-4848, IGR J16320-4751, and IGR J16358-4726) have strong intrinsic photoabsorption and may be high-mass binaries. Their proximity to the region where the tangent to the Galactic spiral arm passes, i.e., to the region of enhanced concentration of young high-mass stars, can serve as an indirect confirmation of this assumption. If our assumption about the positions of the sources in the Norma spiral arm is valid, then we can roughly estimate their heliocentric distances: ∼6–8 kpc.