Constraints on the Persistent Radio Source Associated with FRB 20190520B Using the European VLBI Network
Constraints on the Persistent Radio Source Associated with FRB 20190520B Using the European VLBI Network
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DOI：
10.3847/2041-8213/ad083f
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发表时间：
2023-08
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通讯作者：
S. Bhandari;B. Marcote;N. Sridhar;T. Eftekhari;J. Hessels;D. M. Hewitt;F. Kirsten;O. Ould-Boukattine;Z. Paragi;M. Snelders
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作者：
S. Bhandari;B. Marcote;N. Sridhar;T. Eftekhari;J. Hessels;D. M. Hewitt;F. Kirsten;O. Ould-Boukattine;Z. Paragi;M. Snelders
我们提出了一个可能与快速射电暴源FRB 20190520B相关的连续射电源的超长基线干涉测量（VLBI）观测。利用欧洲VLBI网络，我们发现源在VLBI尺度上是紧凑的，角尺寸小于2.3 mas （3σ）。这对应于一个小于9pc的横向物理尺寸（在主星系的红移z = 0.241处），证实了它是快速射电暴（FRB）持续射电源（PRS），就像第一个已知的中继器FRB 20121102A。该PRS在1.7 GHz时的磁通密度为201±34 μJy，光谱射电亮度为L 1.7 GHz =（3.0±0.5）× 1029 erg s−1 Hz−1（也与FRB 20121102A PRS相似）。与以前的低分辨率观测相比，我们发现在毫弧秒尺度上没有通量被分辨出来。我们改进了PRS位置，与以前的结果相比，精度提高了一个数量级。我们还报道了在1.4 GHz处探测到FRB 20190520B突发，并发现突发位置与PRS位置一致，在≤20 mas处。这有力地支持了它们之间的直接物理联系，以及一个单一的中央引擎同时为爆发和PRS提供动力的假设。我们讨论了风星云中的磁星模型，并给出了它的年龄和假定星云的半径的允许参数空间，为观测到的PRS发射提供动力。另外，我们发现一个吸积驱动的超星云模型也符合我们的观测限制。
We present very long baseline interferometry (VLBI) observations of a continuum radio source potentially associated with the fast radio burst source FRB 20190520B. Using the European VLBI network, we find the source to be compact on VLBI scales with an angular size of <2.3 mas (3σ). This corresponds to a transverse physical size of <9 pc (at the z = 0.241 redshift of the host galaxy), confirming it to be as fast radio burst (FRB) persistent radio source (PRS) like that associated with the first-known repeater FRB 20121102A. The PRS has a flux density of 201 ± 34 μJy at 1.7 GHz and a spectral radio luminosity of L 1.7 GHz = (3.0 ± 0.5) × 1029 erg s−1 Hz−1 (also similar to the FRB 20121102A PRS). Compared to previous lower-resolution observations, we find that no flux is resolved out on milliarcsecond scales. We have refined the PRS position, improving its precision by an order of magnitude compared to previous results. We also report the detection of the FRB 20190520B burst at 1.4 GHz and find the burst position to be consistent with the PRS position, at ≲20 mas. This strongly supports their direct physical association and the hypothesis that a single central engine powers both the bursts and the PRS. We discuss the model of a magnetar in a wind nebula and present an allowed parameter space for its age and the radius of the putative nebula powering the observed PRS emission. Alternatively, we find that an accretion-powered hypernebula model also fits our observational constraints.