Swift J1112.2−8238: a candidate relativistic tidal disruption flare
Swift J1112.2−8238: a candidate relativistic tidal disruption flare
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DOI：
10.1093/mnras/stv1520
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发表时间：
2015-07
影响因子：
4.8
通讯作者：
G. C. Brown;A. Levan;E. Stanway;N. Tanvir;S. Cenko;E. Berger;R. Chornock;A. Cucchiaria
中科院分区：
文献类型：
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作者：
G. C. Brown;A. Levan;E. Stanway;N. Tanvir;S. Cenko;E. Berger;R. Chornock;A. Cucchiaria
我们对雨燕J1112.2−8238进行了观测，并将其确定为候选的相对论性潮汐破裂耀斑。2011年6月，Swift/Burst Alert Telescope（BAT）首次探测到这一爆发，当时它是一个未知的、长寿命的伽马射线瞬变源。我们发现，它的位置是一致的一个暗淡的星系的核心，我们建立了一个可能的红移z = 0.89的基础上，我们解释为混合的[O II] λ3727的双重线的单一发射线。在此红移下，X射线/伽马射线的峰值亮度超过1047 erg s−1，而空间重合的光学瞬变源在早期观测中的亮度为I <$22（z = 0.89时为Mg <$21.4），在雨燕触发后20天。这些属性将Swift J1112.2−8238放在一个非常类似的参数空间区域，与这个类的两个先前确定的成员Swift J1644+57和Swift J2058+0516非常相似。与这些事件一样，高能发射在最初几天显示出可变性的证据，而后期观测，几乎在爆发后3年，表明它现在已经关闭。Swift J1112.2−8238使Swift观察到的此类事件总数达到3个，有趣的是，所有这些事件都是Swift在2013个月内检测到的（截至2015年3月，占其总寿命的3%）。虽然这表明通过详细搜索BAT档案可能会发现更多的例子，但自2011年以来缺乏任何主要候选人意味着这些事件无疑是罕见的。
We present observations of Swift J1112.2−8238, and identify it as a candidate relativistic tidal disruption flare. The outburst was first detected by Swift/Burst Alert Telescope (BAT) in 2011 June as an unknown, long-lived (order of days) gamma-ray transient source. We show that its position is consistent with the nucleus of a faint galaxy for which we establish a likely redshift of z = 0.89 based on a single emission line that we interpret as the blended [O II] λ3727 doublet. At this redshift, the peak X-ray/gamma-ray luminosity exceeded 1047 erg s−1, while a spatially coincident optical transient source had I ∼ 22 (Mg ∼ −21.4 at z = 0.89) during early observations, ∼20 d after the Swift trigger. These properties place Swift J1112.2−8238 in a very similar region of parameter space to the two previously identified members of this class, Swift J1644+57 and Swift J2058+0516. As with those events the high-energy emission shows evidence for variability over the first few days, while late time observations, almost 3 yr post outburst, demonstrate that it has now switched off. Swift J1112.2−8238 brings the total number of such events observed by Swift to three, interestingly all detected by Swift over a ∼3 month period (<3 per cent of its total lifetime as of 2015 March). While this suggests the possibility that further examples may be uncovered by detailed searches of the BAT archives, the lack of any prime candidates in the years since 2011 means these events are undoubtedly rare.