Yalinewich A, Steinberg E, Piran T, Krolik J H
Canadian Institute for Theoretical Astrophysics, 60 St. George St., Toronto, ON M5S 3H8, Canada.
Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027, USA.
Mon Not R Astron Soc. 2019 Aug;487(3):4083-4092. doi: 10.1093/mnras/stz1567. Epub 2019 Jun 10.
When a star gets too close to a supermassive black hole, it is torn apart by the tidal forces. Roughly half of the stellar mass becomes unbound and flies away at tremendous velocities - around 10 km s. In this work, we explore the idea that the shock produced by the interaction of the unbound debris with the ambient medium gives rise to the synchrotron radio emission observed in several tidal disruption event (TDE). We use a moving mesh numerical simulation to study the evolution of the unbound debris and the bow shock around it. We find that as the periapse distance of the star decreases, the outflow becomes faster and wider. A TDE whose periapse distance is a factor of 7 smaller than the tidal radius can account for the radio emission observed in ASASSN-14li. This model also allows us to obtain a more accurate estimate for the gas density around the centre of the host galaxy of ASASSN-14li.
当一颗恒星过于靠近超大质量黑洞时，它会被潮汐力撕裂。大约一半的恒星质量会变得不受束缚，并以极高的速度飞离——速度约为10千米每秒。在这项工作中，我们探讨了这样一种观点：未束缚碎片与周围介质相互作用产生的激波导致了在多个潮汐瓦解事件（TDE）中观测到的同步辐射射电发射。我们使用移动网格数值模拟来研究未束缚碎片及其周围弓形激波的演化。我们发现，随着恒星的近心点距离减小，外流变得更快、更宽。一颗近心点距离比潮汐半径小7倍的TDE可以解释在ASASSN - 14li中观测到的射电发射。该模型还使我们能够更准确地估计ASASSN - 14li宿主星系中心周围的气体密度。
