A Nonrepeating Fast Radio Burst in a Dwarf Host Galaxy
A Nonrepeating Fast Radio Burst in a Dwarf Host Galaxy
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DOI：
10.3847/1538-4357/acc178
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发表时间：
2022-11
期刊：
影响因子：
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通讯作者：
S. Bhandari;A. Gordon;D. R. Scott;L. Marnoch;N. Sridhar;P. Kumar;C. W. James;H. Qiu;
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文献类型：
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作者：
S. Bhandari;A. Gordon;D. R. Scott;L. Marnoch;N. Sridhar;P. Kumar;C. W. James;H. Qiu;
我们目前发现的一个尚未nonrepeating快速射电暴（FRB），FRB 20210117 A，与澳大利亚平方公里阵列探路者（ASKAP），作为一部分的Commensal实时ASKAP快速瞬变调查。爆发的亚弧秒定位导致其宿主星系在z = 0.214（1）处被识别。这个红移远低于729 pc cm−3的源色散测量（DM）的预期值，这是星系际介质和宿主星系的典型贡献。光学观测显示，宿主星系是一个矮星系，几乎没有正在形成的星星-与已知重复的FRB 20121102 A和20190520 B的矮宿主星系非常不同。我们发现一个多余的DM的贡献，从主机和属性到FRB的本地环境。我们没有发现任何来自FRB站点或宿主星系的无线电发射。低磁化环境和缺乏持久的射电源表明FRB源比其他矮宿主星系中发现的更古老，建立了矮星系环境中FRB源的多样性。我们发现我们的观测结果与“超星云”模型完全一致，其中FRB由超吸积黑洞的吸积喷流提供动力。最后，我们的高时间分辨率分析揭示了类似于重复FRB中所见的突发特性。我们鼓励对FRB 20210117 A进行后续观察，以确定任何重复性质。
We present the discovery of an as yet nonrepeating fast radio burst (FRB), FRB 20210117A, with the Australian Square Kilometre Array Pathfinder (ASKAP), as a part of the Commensal Real-time ASKAP Fast Transients Survey. The subarcsecond localization of the burst led to the identification of its host galaxy at z = 0.214(1). This redshift is much lower than what would be expected for a source dispersion measure (DM) of 729 pc cm−3, given typical contributions from the intergalactic medium and the host galaxy. Optical observations reveal the host to be a dwarf galaxy with little ongoing star formation—very different to the dwarf host galaxies of the known repeating FRBs 20121102A and 20190520B. We find an excess DM contribution from the host and attribute it to the FRB’s local environment. We do not find any radio emission from the FRB site or host galaxy. The low magnetized environment and the lack of a persistent radio source indicate that the FRB source is older than those found in other dwarf host galaxies, establishing the diversity of FRB sources in dwarf galaxy environments. We find our observations to be fully consistent with the “hypernebula” model, where the FRB is powered by an accretion jet from a hyperaccreting black hole. Finally, our high time resolution analysis reveals burst characteristics similar to those seen in repeating FRBs. We encourage follow-up observations of FRB 20210117A to establish any repeating nature.