Quasi-periodic dipping in the ultraluminous X-ray source, NGC 247 ULX-1
Quasi-periodic dipping in the ultraluminous X-ray source, NGC 247 ULX-1
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DOI：
10.1093/mnras/stab1473
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发表时间：
2021-04
影响因子：
4.8
通讯作者：
W. Alston;C. Pinto;D. Barret;A. D’Aì;M. Del Santo;H. Earnshaw;A. Fabian;F. Fuerst;E. Kara;P. Kosec;M. Middleton;M. Parker;F. Pintore;A. Robba;T. Roberts;R. Sathyaprakash;D. Walton;E. Ambrosi
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作者：
W. Alston;C. Pinto;D. Barret;A. D’Aì;M. Del Santo;H. Earnshaw;A. Fabian;F. Fuerst;E. Kara;P. Kosec;M. Middleton;M. Parker;F. Pintore;A. Robba;T. Roberts;R. Sathyaprakash;D. Walton;E. Ambrosi
大多数超亮x射线源（ULXs）被认为是恒星质量黑洞或中子星吸积超过爱丁顿极限。从宽频带光谱中确定致密天体的性质和吸积模式目前是一个挑战，但观测到的时序特性提供了对致密天体以及几何和吸积过程细节的深入了解。在这里，我们报告了对超软超亮x射线源NGC 247 ULX-1进行800 ks xmm -牛顿运动的时间分析。x射线光曲线出现深而频繁的下降，其幅度随能带的增加而增加。功率谱和相干分析表明，倾斜优先发生在~ 5和~ 10 ks时间尺度上。这种下降可能是由一个光学厚结构对中央x射线源的掩星引起的，比如吸积盘的翘曲，或者是由吸积盘发射的风的遮挡引起的，或者两者兼而有之。这种行为支持了超软ulx被观察到接近吸积盘的观点。
Most ultraluminous X-ray sources (ULXs) are believed to be stellar mass black holes or neutron stars accreting beyond the Eddington limit. Determining the nature of the compact object and the accretion mode from broad-band spectroscopy is currently a challenge, but the observed timing properties provide insight into the compact object and details of the geometry and accretion processes. Here, we report a timing analysis for an 800 ks XMM–Newton campaign on the supersoft ultraluminous X-ray source, NGC 247 ULX-1. Deep and frequent dips occur in the X-ray light curve, with the amplitude increasing with increasing energy band. Power spectra and coherence analysis reveals the dipping preferentially occurs on ∼5 and ∼10 ks time-scales. The dips can be caused by either the occultation of the central X-ray source by an optically thick structure, such as warping of the accretion disc, or from obscuration by a wind launched from the accretion disc, or both. This behaviour supports the idea that supersoft ULXs are viewed close to edge-on to the accretion disc.