论文标题
明亮的X射线脉冲星：流出如何影响光束，脉动和脉冲相滞后
Bright X-ray Pulsars: how outflows influence beaming, pulsations and pulse phase lags
论文作者
论文摘要
X射线脉冲星（XRP）的极端积聚会导致从积聚盘的内部发射的辐射驱动的流出。流出会影响XRP的明显光度及其通过几何光束的脉动。我们使用Monte Carlo模拟对几何光束和脉冲形成的过程进行建模。我们证实了我们较早的陈述，即由于X射线光子的准直而对光度的强烈扩增与较大的脉冲分数不一致。由于可能高的流出速度（$ \ sim 0.2c $）而导致的相对论畸变会影响此结论。我们证明了光束会导致脉动的相位滞后。在流出形成的吸积腔的开头，相位滞后往往对观察者观察角度敏感。流出几何形状和相位滞后的相应变化的变化可能会影响明亮的X射线脉冲星和ULX中脉动的可检测性。我们推测，由于多个光子反射，强烈的几何光束与吸积腔壁上的较大辐射压力有关。我们期望质量损失率限制几何光束：只有在圆盘的足够大的分数质量损耗率下才能进行强光束。
Extreme accretion in X-ray pulsars (XRPs) results in radiation-driven outflows launched from the inner parts of the accretion disc. The outflows affect the apparent luminosity of the XRPs and their pulsations through the geometrical beaming. We model processes of geometrical beaming and pulse formation using Monte Carlo simulations. We confirm our earlier statement that strong amplification of luminosity due to the collimation of X-ray photons is inconsistent with a large pulsed fraction. Accounting for relativistic aberration due to possibly high outflow velocity ($\sim 0.2c$) does not affect this conclusion. We demonstrate that the beaming causes phase lags of pulsations. Within the opening angle of the accretion cavity formed by the outflows, phase lags tend to be sensitive to observers viewing angles. Variations in outflow geometry and corresponding changes of the phase lags might influence the detectability of pulsation in bright X-ray pulsars and ULXs. We speculate that the strong geometrical beaming is associated with large radiation pressure on the walls of accretion cavity due to multiple photons reflections. We expect that the mass loss rate limits geometrical beaming: strong beaming becomes possible only under sufficiently large fractional mass loss rate from the disc.
