RELATIVISTIC LINES AND REFLECTION FROM THE INNER ACCRETION DISKS AROUND NEUTRON STARS
RELATIVISTIC LINES AND REFLECTION FROM THE INNER ACCRETION DISKS AROUND NEUTRON STARS
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DOI：
10.1088/0004-637x/720/1/205
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发表时间：
2009-08
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影响因子：
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通讯作者：
E. Cackett
中科院分区：
文献类型：
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作者：
E. Cackett
许多中子星低质量x射线双星（lmxb）最近被发现在它们的x射线光谱中显示出宽的，不对称的Fe - K发射线。这些谱线通常被认为是反射光谱中最突出的部分，起源于吸积盘的内部，在那里强相对论效应会使发射谱线变宽。我们对10颗中子星lmxb的Suzaku和XMM-Newton光谱进行了全面、系统的分析，它们都显示出宽的Fe - K发射谱线。在这10个源中，4个是Z源，4个是环礁，2个是吸积的毫秒x射线脉冲星（也是环礁）。对于史瓦西度规来说，Fe - K线可以很好地拟合，并且在大多数情况下，意味着内盘半径的范围很窄（6-15 GM/c2）。这意味着吸积盘在一定的光度范围内延伸到中子星表面附近。连续体模型表明，在大多数观测中，黑体成分（可能与边界层有关）在8至20 keV的x射线发射中占主导地位。因此，这一光谱成分很可能产生了照亮吸积盘的大部分电离通量。因此，我们也用模糊反射模型拟合光谱，其中黑体成分照亮了圆盘。这个模型在大多数情况下都很适合，支持了边界层照亮几何上薄的圆盘的观点。
A number of neutron star low-mass X-ray binaries (LMXBs) have recently been discovered to show broad, asymmetric Fe K emission lines in their X-ray spectra. These lines are generally thought to be the most prominent part of a reflection spectrum, originating in the inner part of the accretion disk where strong relativistic effects can broaden emission lines. We present a comprehensive, systematic analysis of Suzaku and XMM-Newton spectra of 10 neutron star LMXBs, all of which display broad Fe K emission lines. Of the 10 sources, 4 are Z sources, 4 are atolls, and 2 are accreting millisecond X-ray pulsars (also atolls). The Fe K lines are fit well by a relativistic line model for a Schwarzschild metric, and imply a narrow range of inner disk radii (6–15 GM/c2) in most cases. This implies that the accretion disk extends close to the neutron star surface over a range of luminosities. Continuum modeling shows that for the majority of observations, a blackbody component (plausibly associated with the boundary layer) dominates the X-ray emission from 8 to 20 keV. Thus it appears likely that this spectral component produces the majority of the ionizing flux that illuminates the accretion disk. Therefore, we also fit the spectra with a blurred reflection model, wherein a blackbody component illuminates the disk. This model fits well in most cases, supporting the idea that the boundary layer illuminates a geometrically thin disk.