FAST Observations of FRB 20220912A: Burst Properties and Polarization Characteristics

We report the observations of FRB 20220912A using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We conducted 17 observations totaling 8.67 hours and detected a total of 1076 bursts with an event rate up to 390 hr\(^{-1}\). The cumulative energy distribution can be well described...

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Published inarXiv.org
Main Authors Yong-Kun, Zhang, Li, Di, Zhang, Bing, Cao, Shuo, Feng, Yi, Wei-Yang, Wang, Yuan-Hong, Qu, Jia-Rui Niu, Wei-Wei, Zhu, Jin-Lin, Han, Jiang, Peng, Ke-Jia, Lee, Dong-Zi, Li, Luo, Rui, Chen-Hui, Niu, Chao-Wei, Tsai, Wang, Pei, Fa-Yin Wang, Zi-Wei, Wu, Xu, Heng, Yuan-Pei, Yang, Zhang, Jun-Shuo, De-Jiang, Zhou, Yu-Hao, Zhu
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 28.04.2023
Subjects
Bursts
Circular polarization
Coherent scattering
Elastic scattering
Energy distribution
Linear polarization
Magnetars
Magnetospheres
Polarization characteristics
Radiation
Radio telescopes
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Summary:We report the observations of FRB 20220912A using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We conducted 17 observations totaling 8.67 hours and detected a total of 1076 bursts with an event rate up to 390 hr\(^{-1}\). The cumulative energy distribution can be well described using a broken power-law function with the lower and higher-energy slopes of \(-0.38\pm0.02\) and \(-2.07\pm0.07\), respectively. We also report the L band (\(1-1.5\) GHz) spectral index of the synthetic spectrum of FRB~20220912A bursts, which is \(-2.6\pm0.21\). The average rotation measure (RM) value of the bursts from FRB~20220912A is \(-0.08\pm5.39\ \rm rad\,m^{-2}\), close to 0 \(\rm rad\,m^{-2}\) and maintain relatively stable over two months. Most bursts have nearly 100\% linear polarization. About 45\% of the bursts have circular polarization with SNR \(>\) 3, and the highest circular polarization degree can reach 70\%. Our observations suggest that FRB~20220912A is located in a relatively clean local environment with complex circular polarization characteristics. These various behaviors imply that the mechanism of circular polarization of FRBs likely originates from an intrinsic radiation mechanism, such as coherent curvature radiation or inverse Compton scattering inside the magnetosphere of the FRB engine source (e.g. a magnetar).
ISSN:2331-8422