论文标题
脉冲ULX：大脉冲分数不包括强束
Pulsating ULXs: large pulsed fraction excludes strong beaming
论文作者
论文摘要
最近发现的脉动超薄X射线源（ULX）表明，积聚中子恒星（NSS）的明显发光度可以超过Eddington的光度数百倍。实际和表观亮度之间的关系是ULX的理论模型中的关键要素，但仍在争论中。发现的脉动ULX的典型特征是巨大的脉冲部分（PF）。使用Monte Carlo模拟，我们考虑了简单的吸积流的几何形状，并测试由于几何光束和高PF而同时存在较大的亮度扩增的可能性。我们认为，这些因素在很大程度上彼此排除，只有一小部分强烈的ULX脉冲星可以显示出PF以上10％以上。该结论与当前观察结果之间的差异表明，脉动ULX并未强烈束缚，其明显的光度接近实际的亮度。
The recent discovery of pulsating ultra-luminous X-ray sources (ULXs) shows that the apparent luminosity of accreting neutron stars (NSs) can exceed the Eddington luminosity by a factor of hundreds. The relation between the actual and apparent luminosity is a key ingredient in theoretical models of ULXs but it is still under debate. A typical feature of the discovered pulsating ULXs is a large pulsed fraction (PF). Using Monte Carlo simulations, we consider a simple geometry of accretion flow and test the possibility of simultaneous presence of a large luminosity amplification due the geometrical beaming and a high PF. We argue that these factors largely exclude each other and only a negligible fraction of strongly beamed ULX pulsars can show PF above 10 per cent. Discrepancy between this conclusion and current observations indicate that pulsating ULXs are not strongly beamed and their apparent luminosity is close to the actual one.
