Amazing new features of mysterious fast radio bursts challenge current understanding

Artistic conception of the spherical radio telescope with an aperture of five hundred meters (FAST) in China. Credit: Jingchuan Yu

Fast Radio Bursts – A puzzling and ever deeper mystery

An international team of scientists reveals an evolving, magnetized environment and a surprising location for the source of fast radio bursts in deep space – observations that defy current understanding.

Fast radio bursts (FRBs) are millisecond-long cosmic bursts that each produce energy equivalent to the sun’s annual output. Their baffling nature continues to surprise scientists more than 15 years after the discovery of deep-space pulses of electromagnetic radio waves. Now, the newly published research only delves into the mystery surrounding them.

New unexpected observations from a series of cosmic radio bursts by an international team of scientists challenge the prevailing understanding of the physical nature and core engine of FRBs. The researchers, which include astrophysicist Bing Zhang of the University of Nevada, Las Vegas (UNLV), published their findings in the Sept. 21 issue of the journal Nature.

The five hundred meter aperture spherical radio telescope (FAST) is located in a natural depression in the landscape of Guizhou, China. It is the largest single-parabola radio telescope in the world, with a parabola 500 meters (1,600 feet) in diameter and a reception area equivalent to 30 football fields. FAST is expected to maintain its world-class status for the next 20-30 years. With its innovative design, FAST broke the engineering limit of 100 meters for building telescopes and created a new way to build large radio telescopes.

The cosmic observations of the FRB were made in late spring 2021 using the massive five-hundred-meter spherical radio telescope (FAST) in China. The team detected 1,863 flashes in 82 hours in 54 days from an active fast radio burst source called FRB 20201124A. The scientists were led by Heng Xu, Kejia Lee, Subo Dong of Peking University and Weiwei Zhu of the National Astronomical Observatories of China, along with Zhang.

“This is the largest sample of FRB data with polarization information from a single source,” said Lee.

Recent observations of a fast radio burst from our FAST telescope

The five hundred meter aperture spherical radio telescope (FAST), nicknamed Tianyan (“Eye of Heaven / Paradise”) is a radio telescope located in the Dawodang Depression, a natural basin in Pingtang County, Guizhou, in southwest China. It consists of a fixed parabola of 500 meters in diameter built in a natural depression in the landscape. It is the largest full aperture radio telescope in the world and the second largest single dish aperture after the sparsely filled RATAN-600 in Russia.

What makes the latest observations surprising to scientists are the irregular and short-lived variations in the so-called “Faraday rotation measure”, essentially the magnetic field strength and particle density in the vicinity of the FRB source. The variations increased and decreased during the first 36 days of observation and stopped abruptly in the last 18 days before the source went extinct.

“I would compare it to making a film about the surroundings of an FRB source, and our film revealed a complex, dynamically evolving magnetized environment that had never been imagined before,” said Zhang. “Such an environment is not expected for an isolated magnetar. Something else could be in the vicinity of the FRB engine, perhaps a binary companion, “added Zhang.

To observe the FRB’s host galaxy, the team of astronomers also used the 10m Keck telescopes located at Mauna Kea in Hawaii. Zhang says young magnetars are believed to reside in active star-forming regions of a star-forming galaxy, but the optical image of the host galaxy shows that – unexpectedly – it is a metal-rich barred spiral galaxy like ours. Milky Way. The location of the FRB is in a region where there is no significant star-forming activity.

“This position is inconsistent with a young magnetar core motor formed during an extreme explosion such as a long gamma-ray burst or superluminous supernova, widely hypothesized progenitors of active FRB motors,” Dong said.

Reference: “A fast radio burst source at a complex magnetized site in a barred galaxy” by H. Xu, JR Niu, P. Chen, KJ Lee, WW Zhu, S. Dong, B. Zhang, JC Jiang, BJ Wang , JW Xu, CF Zhang, H. Fu, AV Filippenko, EW Peng, DJ Zhou, YK Zhang, P. Wang, Y. Feng, Y. Li, TG Brink, DZ Li, W. Lu, YP Yang, RN Caballero , C. Cai, MZ Chen, ZG Dai, SG Djorgovski, A. Esamdin, HQ Gan, P. Guhathakurta, JL Han, LF Hao, YX Huang, P. Jiang, CK Li, D. Li, H. Li, XQ Li, ZX Li, ZY Liu, R. Luo, YP Men, CH Niu, WX Peng, L. Qian, LM Song, D. Stern, A. Stockton, JH Sun, FY Wang, M. Wang, N. Wang, WY Wang, XF Wu, S. Xiao, SL Xiong, YH Xu, RX Xu, J. Yang, X. Yang, R. Yao, QB Yi, YL Yue, DJ Yu, WF Yu, JP Yuan, BB Zhang, SB Zhang, SN Zhang, Y. Zhao, WK Zheng, Y. Zhu and JH Zou, September 21, 2022, Nature.
DOI: 10.1038 / s41586-022-05071-8

The study appeared Sept. 21 in the journal Nature and includes 74 co-authors from 30 institutions. In addition to the UNLV, Peking University and the National Astronomical Observatories of China, the collaborating institutions also include Purple Mountain Observatory, Yunnan University, UC Berkeley, Caltech,

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