Milliarcsecond-scale spectrum of the persistent radio source associated with FRB 20190417A and constraints for FRB 20181030A
INAF – Istituto di Astrofisica e Planetologia Spaziali（意大利国家天体物理研究所空间天体物理与行星科学研究所）；South-Western Institute for Astronomy Research, Yunnan University（云南大学西南天文研究所）；INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（意大利国家天体物理研究所博洛尼亚空间天体物理与科学观测站）；Dipartimento di Fisica, Università della Calabria（卡拉布里亚大学物理系）；Laboratori Nazionali di Frascati, INFN (Istituto Nazionale di Fisica Nucleare)（意大利国家核物理研究所弗朗卡蒂国家实验室）；The Hong Kong Institute for Astronomy and Astrophysics, the University of Hong Kong（香港大学香港天文及天体物理研究所）；Department of Physics, the University of Hong Kong（香港大学物理系）
G. Bruni, L. Piro, Y. -P. Yang, L. Nicastro, A. Rossi, E. Palazzi, E. Maiorano, S. Savaglio, B. Zhang
We aim to confirm the compact nature and constrain the radio spectra of candidate persistent radio sources (PRSs) associated with repeating fast radio bursts (FRBs). We performed European VLBI Network (EVN) observations at 5 and 8 GHz targeting two candidates identified in a recent VLA survey. We measured flux densities and upper limits at milliarcsecond resolution and combined them with published VLBI data at lower frequencies to derive spectral constraints. We detect a compact source associated with FRB 20190417A at 5 GHz with a flux density of $150\pm45$ uJy, while no detection is obtained at 8 GHz. The source is unresolved and has a brightness temperature $T_{\rm b}>10^{5}$ K, confirming its non-thermal nature. Combining our measurement with VLBI data at 1.4 GHz, we derive a spectral index $α= -0.19 \pm 0.29$, consistent with a nearly flat spectrum. This makes FRB 20190417A only the second PRS with a spectral index constrained using VLBI data. The inferred luminosity places the source on the proposed $L_ν$-|RM| relation. Including this source yields a scatter of $σ_Δ= 0.65$, corresponding to $\hatα|ε| = 1.5 \pm 0.7$, consistent with forward shocks in the free-expansion phase or young pulsar wind nebulae. For the candidate PRS associated with FRB 20181030A, we report upper limits of 80 uJy at 5 GHz and 150 uJy at 8 GHz, corresponding to $L_{5\,\mathrm{GHz}} \lesssim 3.8 \times 10^{25}\ {\rm erg\ s^{-1}\ Hz^{-1}}$, and implying a steep spectral index ($α\lesssim -1.2$) if the VLA emission arises from a compact component. Our results highlight the importance of VLBI in isolating compact emission from FRB engines and provide one of the few spectral constraints for PRSs at milliarcsecond resolution. The consistency of FRB 20190417A with the $L_ν$-|RM| relation supports a nebular origin for the persistent emission.
FRB 190520B embedded in a magnetar wind nebula and supernova remnant: luminous persistent radio source, decreasing dispersion measure and large rotation measure
最近，FRB 190520 B被500米口径球面射电望远镜（FAST）发现，具有最大的河外色散测量（DM）。DM超过星系际介质和银河系的贡献估计为$\sim 900$ pc cm $^{-3}$，这是近十倍高于其他快速射电暴（FRB）的主机星系。DM以每天$\sim0.1$ pc cm $^{-3}$的速率降低。它是第二个与紧凑持续射电源（PRS）相关的FRB。发现旋转度量（RM）大于$1.8 \times 10^{5} \mathrm{rad} ~\mathrm{m}^{-2}$。在这封信中，我们认为FRB 190520 B是由大质量恒星的核心坍缩形成的年轻magentar提供动力，嵌入在磁星风星云（MWN）和超新星遗迹（SNR）的复合物中。磁星的能量注入驱动MWN和SN喷出物一起演化，PRS由MWN的同步辐射产生。磁星的内部磁场为$B_{\text{int}}\sim (2-4)\times 10^{16}$ G，年龄为$t_{\text{age}}\sim 14-22$ yr。致密的SN喷出物和冲击壳贡献了所观察到的DM和RM的很大一部分。我们的模型可以很自然地同时解释FRB 190520 B的发光PRS、下降DM和极端RM。
A repeating fast radio burst associated with a persistent radio source
快速射电暴（FRB）的色散扫描被用来探测星系际介质中的电离重子含量，它被认为是控制总的河外色散的主要因素。虽然主星系的色散措施（DM）的贡献似乎是最FRB的小，在至少一种情况下，有极端的磁离子局部环境和紧凑的持久性射电源的证据。在这里，我们报告的检测和定位的重复FRB 20190520 B，这是一个紧凑的，持久的无线电源，并与矮宿主星系的高比恒星形成率在红移$z=0.241\pm0.001$。估计的宿主星系DM $\approx 903^{+72}_{-111}$ pc cm $^{-3}$，近一个数量级高于平均的FRB宿主星系，远远超过DM的星系际介质的贡献。因此，在没有准确的宿主星系识别的情况下，推断FRB的红移是有必要的。
The Persistent Radio Sources and Multi-wavelength Counterparts of Fast Radio Bursts in Massive Binary Systems
School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）；Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education（教育部现代天文与天体物理重点实验室（南京大学））；Department of Astronomy, School of Physical Sciences, University of Science and Technology of China（中国科学技术大学物理学院天文学系）
A Persistently Active Fast Radio Burst source Embedded in an Expanding Supernova Remnant
Central China Normal University（华中师范大学）；Tsinghua University（清华大学）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Yunnan University（云南大学）；Zhejiang Laboratory（之江实验室）；University of Chinese Academy of Sciences（中国科学院大学）；Xinjiang Astronomical Observatory, Chinese Academy of Sciences（中国科学院新疆天文台）；Zhejiang University（浙江大学）；University of Nevada, Las Vegas（内华达大学拉斯维加斯分校）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；University of Science and Technology of China（中国科学技术大学）；CSIRO（澳大利亚联邦科学与工业研究组织）；Western Sydney University（西悉尼大学）；Shanghai Jiao Tong University（上海交通大学）；National Astronomical Observatory of Japan（日本国立天文台）
A unified model of active repeating fast radio bursts associated with persistent radio sources
School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）；Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education（教育部现代天文学和天体物理重点实验室（南京大学））；Research Center for Astronomical Computing, Zhejiang Laboratory（浙江实验室天体计算研究中心）；Institute for Astronomy, School of Physics, Zhejiang University（浙江大学物理学院天体物理研究所）；School of Physics and Physical Engineering, Qufu Normal University（曲阜师范大学物理与光电工程学院）；Department of Astronomy, University of Science and Technology of China（中国科学技术大学天文学系）；Department of Physics, The University of Hong Kong（香港大学物理系）
Flux Variations of Fast Radio Bursts and Their Persistent Radio Sources: Evidence for a Shared Progenitor
Central China Normal University（华中师范大学）；Tsinghua University（清华大学）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；The Hong Kong Institute for Astronomy and Astrophysics, The University of Hong Kong（香港大学天体物理研究所）；Department of Physics, The University of Hong Kong（香港大学物理系）；Nevada Center for Astrophysics, University of Nevada, Las Vegas（内华达大学拉斯维加斯分校天体物理中心）；Department of Physics and Astronomy, University of Nevada, Las Vegas（内华达大学拉斯维加斯分校物理与天文系）
Fast radio burst - persistent radio source systems III. The relation between PRS luminosity and FRB rotation measure
INAF-Istituto di Radio Astronomia (IRA)（意大利国家天体物理研究所射电天文研究所）；Centre for Radio Astronomy Techniques and Technologies (RATT), Department of Physics and Electronics, Rhodes University（罗德斯大学物理与电子学院射电天文技术与方法中心）；South African Radio Astronomy Observatory（南非射电天文观测台）；INAF-Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；Scuola Universitaria Superiore IUSS Pavia（帕维亚高等大学）；INAF–Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano（意大利国家天体物理研究所米兰空间天体物理学与宇宙物理学研究所）；Dipartimento di Fisica e Astronomia, Universitá di Bologna（博洛尼亚大学物理与天文学系）；Dipartimento di Fisica, Università di Tr（特兰托大学物理系）
A MeerKAT search for persistent radio sources towards twenty-five localised Fast Radio Bursts
North-West University（西北大学）；University of South Africa（南非大学）；University of Nigeria（尼日利亚大学）；National Institute for Theoretical and Computational Sciences (NITheCS)（国家理论与计算科学研究所）；South African Radio Astronomy Observatory（南非射电天文台）；Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester（曼彻斯特大学物理与天文学系乔德雷克天体物理学中心）
The spectrum of the persistent radio source associated with FRB 20190417A
Istituto Nazionale di Astrofisica - Istituto di Radioastronomia（意大利国家天体物理研究所射电天文研究所）；South African Radio Astronomy Observatory（南非射电天文台）；Centre for Radio Astronomy Techniques and Technologies (RATT), Department of Physics and Electronics, Rhodes University（罗德斯大学物理与电子学院射电天文技术与方法中心）；Istituto Nazionale di Astrofisica - Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；Dipartimento di Fisica e Astronomia - Università di Bologna（博洛尼亚大学物理与天文学系）；Scuola Universitaria Superiore IUSS Pavia（帕维亚高等大学）
An extreme magneto-ionic environment associated with the fast radio burst source FRB 121102
快速射电暴（英语：Fast radio burst，缩写为FRB）是一种毫秒级的、未知物理来源的河外射电闪光。FRB 121102是唯一已知的重复FRB源，它位于一个红移z = 0.193的矮星系的恒星形成区，在空间上与一个紧凑的持久射电源重合。爆发的起源，持续源的性质，以及当地环境的属性仍然存在争议。在这里，我们展示了在源坐标系中，在极高且可变的法拉第旋转测量下，除了窄的（< 30 μ s）时间结构外，在相隔7个月的历元上，在RM_src = +1.46 x 10^5 rad m^-2和+1.33 x 10^5 rad m^-2时，显示出~100%线偏振发射的爆发。FRB 121102的大的和可变的旋转测量表明，它是在一个极端的和动态的磁离子环境，而短的爆发持续时间主张中子星的起源。到目前为止，只有在大质量黑洞（M_BH > 10^4 MSun）附近才能观测到如此大的自转量。事实上，持久射电源的性质与低光度、吸积的大质量黑洞的性质是相容的。因此，爆发可能来自这样环境中的中子星。然而，观察到的特性也可以用其他模型来解释，例如围绕着年轻中子星的高磁化风星云或超新星遗迹。
Unveiling the Local Environment of FRB 20220912A: Sub-arcsecond $4-26$ GHz Radio Continuum Mapping
National Centre for Radio Astrophysics, Tata Institute of Fundamental Research（塔塔基础研究所射电天体物理国家中心）；Indian Institute of Technology Kanpur（坎普尔印度理工学院）；McGill University（麦吉尔大学）；Northwestern University（西北大学）；University of Amsterdam（阿姆斯特丹大学）
Fast radio burst - persistent radio source systems I. A 1.2 GHz search and catalog definition
INAF-Istituto di Radio Astronomia (IRA)（意大利国家天体物理研究所射电天文研究所）；Centre for Radio Astronomy Techniques and Technologies (RATT), Department of Physics and Electronics, Rhodes University（罗德斯大学物理与电子学院射电天文技术与方法中心）；South African Radio Astronomy Observatory（南非射电天文观测台）；INAF-Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；Scuola Universitaria Superiore IUSS Pavia（帕维亚高等大学学院）；INAF–Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano（意大利国家天体物理研究所米兰空间天体物理与宇宙物理研究所）；Dipartimento di Fisica e Astronomia, Universitá di Bologna（博洛尼亚大学物理与天文学系）；Dipartimento di Fisica, Università di Trento（特伦托大学物理系）
