A Huge Drop in the X-Ray Luminosity of the Nonactive Galaxy RX J1242.6–1119A, and the First Postflare Spectrum: Testing the Tidal Disruption Scenario
A Huge Drop in the X-Ray Luminosity of the Nonactive Galaxy RX J1242.6–1119A, and the First Postflare Spectrum: Testing the Tidal Disruption Scenario
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DOI：
10.1086/382046
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发表时间：
2004-02
期刊：
影响因子：
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通讯作者：
S. Komossa;J. Halpern;N. Schartel;G. Hasinger;M. Santos-Lleo;P. Predehl
中科院分区：
文献类型：
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作者：
S. Komossa;J. Halpern;N. Schartel;G. Hasinger;M. Santos-Lleo;P. Predehl
近年来，有间接证据表明，许多附近的非活动星系拥有静止的超大质量黑洞。关于黑洞出现频率、质量和自旋的知识，对于研究黑洞的生长、星系和活动星系核的形成和演化具有广泛的相关性。有人认为，超大质量黑洞存在的一个不可避免的后果，以及它们在非活动星系中存在的最佳诊断，将是黑洞捕获的恒星偶尔发生的潮汐破坏。这些事件以发光耀斑的形式表现出来，这些耀斑是由破裂的星星的碎片吸积到黑洞中而产生的。在过去的几年里，光学不活跃星系中出现了候选事件。这是我们第一次以高空间和光谱分辨率观察星系中有史以来记录的最极端的变化事件之一。在这里，我们报告测量的X射线源RX J1242-1119与X射线天文台钱德拉和XMM-牛顿的光度下降了约200倍，并进行测试的青睐爆发的情况下，潮汐破坏的星星的超大质量黑洞。我们发现，检测到的“低状态”排放的属性，使它仍然必须与耀斑。幂律形状的耀斑后X射线光谱表明“硬化”相比，爆发。推断出的黑洞质量，释放的能量，和事件的持续时间有利于吸积事件的形式预期从（部分或全部）潮汐破坏的星星。
In recent years, indirect evidence has emerged suggesting that many nearby nonactive galaxies harbor quiescent supermassive black holes. Knowledge of the frequency of occurrence of black holes, of their masses and spins, is of broad relevance for studying black hole growth and galaxy and active galactic nuclei formation and evolution. It has been suggested that an unavoidable consequence of the existence of supermassive black holes, and the best diagnostic of their presence in nonactive galaxies, would be occasional tidal disruption of stars captured by the black holes. These events manifest themselves in the form of luminous flares powered by accretion of debris from the disrupted star into the black hole. Candidate events among optically nonactive galaxies emerged in the past few years. For the first time, we have looked with high spatial and spectral resolution at one of these most extreme variability events ever recorded among galaxies. Here we report measuring a factor of ~200 drop in luminosity of the X-ray source RX J1242-1119 with the X-ray observatories Chandra and XMM-Newton, and perform tests of the favored outburst scenario, tidal disruption of a star by a supermassive black hole. We show that the detected "low-state" emission has properties such that it must still be related to the flare. The power-law shaped postflare X-ray spectrum indicates a "hardening" compared to outburst. The inferred black hole mass, the amount of liberated energy, and the duration of the event favor an accretion event of the form expected from the (partial or complete) tidal disruption of a star.