Late-time radio observations of the short GRB 200522A: constraints on the magnetar model
Late-time radio observations of the short GRB 200522A: constraints on the magnetar model
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DOI：
10.1093/mnrasl/slab046
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发表时间：
2021-05
期刊：
影响因子：
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通讯作者：
G. Bruni;B. O’Connor;T. Matsumoto;E. Troja;T. Piran;L. Piro;R. Ricci
中科院分区：
文献类型：
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作者：
G. Bruni;B. O’Connor;T. Matsumoto;E. Troja;T. Piran;L. Piro;R. Ricci
GRB 200522 A是一个红移z=0.554的短持续时间伽玛射线暴（GRB），其特征是明亮的红外对应物。对观测到的辐射的一种可能的解释是，由一颗快速旋转和高度磁化的中子星星（称为磁星）提供动力的发光千诺瓦的开始。一个明亮的射电耀斑，从千诺瓦喷出物与周围介质的相互作用所产生的，是这个模型的预测。虽然现有的数据集仍然可以进行多种解释（例如余辉，r-过程kilonova，磁星动力kilonova），但对这种爆发的长期无线电监测可能是区分模型的关键。我们提出了我们的最新的时间上限的伽玛暴200522 A的射电发射，进行了卡尔G。Jansky超大型阵列在爆发后288天。对于能量为Eej = 1053 erg的千诺瓦喷出物，正如对长寿磁星遗迹的预期，我们已经可以排除喷出物质量为Mej。0.03 M，环暴流密度最可能的范围为n & 10−3 cm−3。在合并后的203 -10年的时间尺度上进行的观测将探测到更大的喷出物质量，最高可达兆焦耳0.1兆，为磁星情景提供了一个强大的测试。
GRB 200522A is a short duration gamma-ray burst (GRB) at redshift z=0.554 characterized by a bright infrared counterpart. A possible, although not unambiguous, interpretation of the observed emission is the onset of a luminous kilonova powered by a rapidly rotating and highly-magnetized neutron star, known as magnetar. A bright radio flare, arising from the interaction of the kilonova ejecta with the surrounding medium, is a prediction of this model. Whereas the available dataset remains open to multiple interpretations (e.g. afterglow, r-process kilonova, magnetar-powered kilonova), long-term radio monitoring of this burst may be key to discriminate between models. We present our late-time upper limit on the radio emission of GRB 200522A, carried out with the Karl G. Jansky Very Large Array at 288 days after the burst. For kilonova ejecta with energy Eej ≈1053 erg, as expected for a long-lived magnetar remnant, we can already rule out ejecta masses Mej . 0.03M for the most likely range of circumburst densities n & 10−3 cm−3. Observations on timescales of ≈ 3-10 yr after the merger will probe larger ejecta masses up to Mej ∼ 0.1M , providing a robust test to the magnetar scenario.