Multiband light curves of tidal disruption events
Multiband light curves of tidal disruption events
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DOI：
10.1111/j.1365-2966.2010.17448.x
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发表时间：
2010-08
影响因子：
4.8
通讯作者：
G. Lodato;Elena Rossi Dipartimento di Fisica;U. Milano;I. O. T. Physics;The Hebrew University;Jérusalem
中科院分区：
文献类型：
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作者：
G. Lodato;Elena Rossi Dipartimento di Fisica;U. Milano;I. O. T. Physics;The Hebrew University;Jérusalem
明确检测恒星的潮汐破坏将有助于评估静止星系中超大质量黑洞的存在和质量。它还将通过恒星注入黑洞影响的潮汐球的速率，提供有关核球尺度恒星过程（例如二体弛豫）的宝贵信息。反过来，这个速率对于预测致密物体螺旋的引力辐射发射至关重要。潮汐破坏事件的特征被认为是恒星碎片到黑洞的回退率，以 t -5/3 减小。通常假设该质量通量会产生随时间以相同速率减小的发光信号。在本文中，我们计算了这种吸积事件产生的单色光变曲线。与之前的研究不同，我们对回退率和超爱丁顿吸积物理采用了更现实的描述。我们还提供光学、紫外线 (UV) 和 X 射线的同步光变曲线。我们表明，几个月后，光学和紫外光曲线缩放为 t -5/12 ，因此比 t -5/3 行为显着平坦，这只是测辐射热光曲线的特权。在早期，对于黑洞质量 < 10 7 M ⊙ ，风发射占主导地位：在大约一个月达到 10 41 -10 43 erg s -1 的峰值后，光变曲线急剧下降为 ~t -2.6 ，直到圆盘贡献占据主导地位。相反，X 射线波段是检测 t -5/3 “铁证”行为的最佳位置，尽管它仅显示大约一年，然后发射呈指数级陡峭。
Unambiguous detection of the tidal disruption of a star would allow an assessment of the presence and masses of supermassive black holes in quiescent galaxies. It would also provide invaluable information on bulge-scale stellar processes (such as two-body relaxation) via the rate at which stars are injected into the tidal sphere of influence of the black holes. This rate, in turn, is essential to predict gravitational radiation emission by compact object inspirals. The signature of a tidal disruption event is thought to be a fallback rate for the stellar debris on to the black hole that decreases as t -5/3 . This mass flux is often assumed to yield a luminous signal that decreases in time at the same rate. In this paper, we calculate the monochromatic light curves arising from such an accretion event. Differently from previous studies, we adopt a more realistic description of the fallback rate and of the super-Eddington accretion physics. We also provide simultaneous light curves in optical, ultraviolet (UV) and X-rays. We show that, after a few months, optical and UV light curves scale as t -5/12 , and are thus substantially flatter than the t -5/3 behaviour, which is a prerogative of the bolometric light curve, only. At earlier times and for black hole masses < 10 7 M ⊙ , the wind emission dominates: after reaching a peak of 10 41 -10 43 erg s -1 at roughly a month, the light curve decreases steeply as ~t -2.6 , until the disc contribution takes over. The X-ray band, instead, is the best place to detect the t -5/3 'smoking gun' behaviour, although it is displayed only for roughly a year, before the emission steepens exponentially.