Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
Nature. 2012 May 2;485(7397):217-20. doi: 10.1038/nature10990.
The flare of radiation from the tidal disruption and accretion of a star can be used as a marker for supermassive black holes that otherwise lie dormant and undetected in the centres of distant galaxies. Previous candidate flares have had declining light curves in good agreement with expectations, but with poor constraints on the time of disruption and the type of star disrupted, because the rising emission was not observed. Recently, two 'relativistic' candidate tidal disruption events were discovered, each of whose extreme X-ray luminosity and synchrotron radio emission were interpreted as the onset of emission from a relativistic jet. Here we report a luminous ultraviolet-optical flare from the nuclear region of an inactive galaxy at a redshift of 0.1696. The observed continuum is cooler than expected for a simple accreting debris disk, but the well-sampled rise and decay of the light curve follow the predicted mass accretion rate and can be modelled to determine the time of disruption to an accuracy of two days. The black hole has a mass of about two million solar masses, modulo a factor dependent on the mass and radius of the star disrupted. On the basis of the spectroscopic signature of ionized helium from the unbound debris, we determine that the disrupted star was a helium-rich stellar core.
潮汐破坏和吸积恒星所产生的辐射耀斑可用作超大质量黑洞的标志，这些黑洞在遥远星系的中心潜伏且未被探测到。先前的候选耀斑的光曲线呈下降趋势，与预期非常吻合，但由于未观察到上升发射，因此对破坏时间和被破坏恒星的类型的约束较差。最近，发现了两个“相对论性”潮汐破坏候选事件，它们的极端 X 射线光度和同步辐射无线电发射都被解释为相对论喷流发射的开始。在这里，我们报告了一个位于红移为 0.1696 的不活跃星系核区的明亮紫外-光学耀斑。观测到的连续谱比简单吸积碎屑盘预期的要冷，但光曲线的良好采样上升和下降遵循预测的质量吸积率，可以进行建模以确定破坏时间的准确度为两天。黑洞的质量约为两百万个太阳质量，取决于破坏的恒星的质量和半径的一个因子。基于来自未束缚碎屑的电离氦的光谱特征，我们确定被破坏的恒星是富氦恒星核心。
