发表机构
Institute of Physics of the Czech Academy of Sciences; Department of Theoretical Physics and Astrophysics, Masaryk University; Astronomical Institute of the Czech Academy of Sciences（捷克科学院物理研究所; 马萨里克大学理论与天体物理学系; 捷克科学院天文研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究恒星-吸积盘碰撞，通过三维局部辐射流体动力学模拟，改变多种参数，发现不同参数对耀斑等的影响，给出峰值光度和耀斑持续时间与系统参数的标度关系，应用于GSN 069，揭示特定参数组合可重现QPE源特征。
AI 中文摘要
准周期爆发（QPEs）是核瞬变现象，产生明亮、重复的软X射线耀斑叠加在宁静发射之上。一种有前景的解释是它们由恒星-吸积盘碰撞驱动，恒星穿过围绕超大质量黑洞的吸积盘，引发激波并产生密集外流，从中辐射出能量。我们对恒星-吸积盘碰撞进行了系统研究，将碰撞的物理参数与产生的外流和总辐射光度联系起来。进行了三维局部辐射流体动力学模拟，改变吸积盘表面密度、垂直密度分布、恒星速度和半径以及局部碰撞角度。重点关注恒星在碰撞中未受扰动的情况。发现恒星速度和吸积盘表面密度的变化对外激波和外流形态影响不大，但更快的恒星产生更亮的耀斑，更密集的吸积盘主要增加耀斑持续时间。增大恒星半径增加前向外流动量并产生更亮更长的耀斑。更集中于中心的吸积盘产生更亮更短的耀斑。更倾斜的交叉减少两个外流的动量和光度不对称并延长耀斑。提供了峰值光度和耀斑持续时间与各系统参数的经验标度关系，并应用于GSN 069。最佳候选解倾向于一颗半径约为太阳半径的逆行轨道恒星与一个具有垂直集中密度分布的致密潮汐瓦解事件后吸积盘碰撞。我们的发现表明系统参数的特定组合可以重现QPE源中观测到的特征耀斑幅度、持续时间、占空比和强弱耀斑模式。
英文摘要
Quasi-periodic eruptions (QPEs) are nuclear transients producing bright, repeating soft X-ray flares superimposed on quiescent emission. A promising interpretation is that they are powered by star-disc collisions, in which a star crosses an accretion disc around a supermassive black hole, drives shocks, and launches dense outflows from which radiation emerges. We present a systematic study of star-disc collisions, linking the physical parameters of the collision to the resulting outflows and emerging bolometric luminosities. We perform three-dimensional local radiation-hydrodynamics simulations, varying the disc surface density and vertical density profiles, stellar velocity and radius, and local collision angle. We focus on the regime where the star remains unperturbed by the collision. We find that variations in stellar velocity and accretion disc surface density leave the bow shock and outflow morphology largely unchanged. Faster stars produce brighter flares, while denser discs mainly increase the flare duration. Increasing the stellar radius increases the momentum of the forward outflow and produces brighter and longer flares. More centrally concentrated discs yield brighter and shorter flares because radiation escapes more efficiently through outer low-density layers. More oblique crossings reduce the momentum and luminosity asymmetry of two outflows, and lengthen the flares. We provide empirical scalings of the peak luminosity and flare duration with the individual system parameters and apply them to GSN 069. The best candidate solutions favour a star with a radius $\sim R_\odot$ on a retrograde orbit, colliding with a dense post-TDE disc with a vertically concentrated density profile. Our findings suggest that specific combinations of system parameters can reproduce characteristic flare amplitudes, durations, duty cycles, and strong-weak flare patterns observed in QPE sources.
CommentsAccepted in A&A
