Short GRB 160821B: A Reverse Shock, a Refreshed Shock, and a Well-sampled Kilonova
Short GRB 160821B: A Reverse Shock, a Refreshed Shock, and a Well-sampled Kilonova
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DOI：
10.3847/1538-4357/ab38bb
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发表时间：
2019-05
期刊：
影响因子：
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通讯作者：
G. Lamb;N. Tanvir;A. Levan;A. Levan;A. D. U. Postigo;A. D. U. Postigo;K. Kawaguchi;K. Kawaguchi-K.-Kawag
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作者：
G. Lamb;N. Tanvir;A. Levan;A. Levan;A. D. U. Postigo;A. D. U. Postigo;K. Kawaguchi;K. Kawaguchi-K.-Kawag
我们报告我们的识别的光学余辉和宿主星系的短持续时间伽玛射线暴sGRB 160821 B。其光谱红移z = 0.162，是雨燕发现的最低红移短持续时间伽玛射线暴（sGRB）之一。我们使用一系列地面设施以及哈勃太空望远镜，XMM-牛顿和斯威夫特进行了密集的后续活动，除了复杂的余辉外，还显示了后期光学和近红外发射过量的证据。X射线频率下的余辉光变曲线显示出一个狭窄的喷流，度，它在爆发后>1天被一个比产生主伽玛暴的初始流出能量明显更多的较慢流出所刷新。对5 GHz射电余辉的观测表明，一个反向激波进入了一个轻度磁化的壳层。光学和近红外线的过剩比与GW 170817相关的AT 2017 gfo更微弱，并且可以很好地解释为动态喷出物质量Mdyn =（1.0 ± 0.6）× 10−3 M的千诺瓦和Mpm =（1.0 ± 0.6）× 10−2 M的长期（合并后）喷出物质量，这与双中子星星合并导致短寿命的大质量中子星星一致。这个光学和近红外数据集提供了迄今为止没有引力波触发的最佳采样的千诺瓦光变曲线。
We report our identification of the optical afterglow and host galaxy of the short-duration gamma-ray burst sGRB 160821B. The spectroscopic redshift of the host is z = 0.162, making it one of the lowest redshift short-duration gamma-ray bursts (sGRBs) identified by Swift. Our intensive follow-up campaign using a range of ground-based facilities as well as Hubble Space Telescope, XMM-Newton, and Swift, shows evidence for a late-time excess of optical and near-infrared emission in addition to a complex afterglow. The afterglow light curve at X-ray frequencies reveals a narrow jet, deg, that is refreshed at >1 day post-burst by a slower outflow with significantly more energy than the initial outflow that produced the main GRB. Observations of the 5 GHz radio afterglow shows a reverse shock into a mildly magnetized shell. The optical and near-infrared excess is fainter than AT2017gfo associated with GW170817, and is well explained by a kilonova with dynamic ejecta mass Mdyn = (1.0 ± 0.6) × 10−3 M⊙ and a secular (post-merger) ejecta mass with Mpm = (1.0 ± 0.6) × 10−2 M⊙, consistent with a binary neutron star merger resulting in a short-lived massive neutron star. This optical and near-infrared data set provides the best-sampled kilonova light curve without a gravitational wave trigger to date.