AI 中文总结
研究围绕超大质量黑洞的恒星-盘碰撞，通过三维模拟展示相互作用过程，包括碎片云形成、流-盘碰撞等，从模拟结果推断耀斑持续时间等，支持每个恒星轨道一个耀斑观点，并讨论对QPE定时等的影响。
AI 中文摘要
准周期爆发（QPEs）是重复出现的软X射线核瞬变现象，复发时间为数小时至数天，耀斑占空比约为10%-20%。QPEs的许多方面可建模为一个恒星质量的轨道器与吸积盘相交，产生一个受激碎片云及辐射耀斑。我们展示了围绕10^6 M⊙超大质量黑洞的恒星-盘相互作用的三维Athena++流体动力学模拟，包括黑洞的潮汐势、盘的开普勒旋转以及与观测相似的轨道周期。每次盘遭遇后，新剥离的恒星碎片离开希尔球形成一个扩展的、不对称的、大致三轴的流。随后的流-盘碰撞将恒星碎片和盘气体激波到高比能并驱动类似风的外流。在较长轨道周期，受激恒星碎片主导高比能碎片，而在较短轨道周期，受激盘能量可能相似。从模拟中随时间测量的受激恒星质量，我们推断耀斑持续时间由恒星碎片流与盘碰撞所需时间设定，与观测到的约10%-20%的恒定占空比一致，与轨道周期无关。总受激碎片能量与QPE耀斑能量学一致。我们的结果支持每个恒星轨道有一个可观测耀斑，除了可能在最短轨道周期，此时受激恒星和盘能量可能相似。流的质心相对于恒星、流密度和其他属性的变化可导致耀斑峰值时间相对于恒星-盘碰撞时间产生不同变化。我们讨论了结果对QPE定时和星系核中其他瞬变现象的影响。
英文摘要
Quasi-periodic eruptions (QPEs) are repeating soft X-ray nuclear transients with recurrence times of hours-days and flare duty cycles of $\sim$10-20%. Many aspects of QPEs can be modeled as a stellar-mass orbiter that intersects an accretion disk producing a shocked debris cloud and a flare of radiation. We present three-dimensional Athena++ hydrodynamic simulations of star-disk interactions around a $10^{6}\,M_\odot$ supermassive black hole, including the black hole's tidal potential, the disk's Keplerian rotation, and orbital periods similar to those observed. After each disk encounter, freshly stripped stellar debris exits the Hill sphere to form an extended, asymmetric, roughly triaxial stream. Subsequent stream-disk collisions shock both stellar debris and disk gas to high specific energies and drive a wind-like outflow. At larger orbital periods the shocked stellar debris dominates the high specific energy debris, while at shorter orbital periods the shocked disk energy can be similar. From the shocked stellar mass measured in the simulations over time, we infer flare durations set by the time it takes the stellar debris stream to collide with the disk, consistent with the observed constant duty cycle of $\sim$10-20%, independent of orbital period. The total shocked debris energy is consistent with QPE flare energetics. Our results favor one observable flare per stellar orbit except perhaps at the shortest orbital periods where the shocked star and disk energetics can be similar. Variations in the stream's center of mass relative to the star, the stream density, and other properties can produce diverse changes in the time of the flare's peak relative to the time of the star-disk collision. We discuss the implications of our results for QPE timing and for other transients in galactic nuclei.
Comments15 pages, 8 figures, 2 tables; submitted to ApJ
