@article{886d02c6bb954b1c8ce854535b7c9bbc,
title = "Fine Structures of Radio Bursts from Flare Star AD Leo with FAST Observations",
abstract = "Radio bursts from nearby active M-dwarfs have been frequently reported and extensively studied in solar or planetary paradigms. Whereas, their substructures or fine structures remain rarely explored despite their potential significance in diagnosing the plasma and magnetic field properties of the star. Such studies in the past have been limited by the sensitivity of radio telescopes. Here we report the inspiring results from the high time-resolution observations of a known flare star AD Leo with the Five-hundred-meter Aperture Spherical radio Telescope. We detected many radio bursts in the 2 days of observations with fine structures in the form of numerous millisecond-scale sub-bursts. Sub-bursts on the first day display stripe-like shapes with nearly uniform frequency drift rates, which are possibly stellar analogs to Jovian S-bursts. Sub-bursts on the second day, however, reveal a different blob-like shape with random occurrence patterns and are akin to solar radio spikes. The new observational results suggest that the intense emission from AD Leo is driven by electron cyclotron maser instability, which may be related to stellar flares or interactions with a planetary companion.",
author = "Jiale Zhang and Hui Tian and Philippe Zarka and Louis, {Corentin K.} and Hongpeng Lu and Dongyang Gao and Xiaohui Sun and Sijie Yu and Bin Chen and Xin Cheng and Ke Wang",
note = "Funding Information: We are grateful for the financial support from NSFC grants 12250006. P.Z. acknowledges funding from the ERC under the European Union's Horizon 2020 research and innovation program (grant agreement No. 101020459—Exoradio). C.K.L.'s work at the Dublin Institute for Advanced Studies was funded by the Science Foundation Ireland grant 18/FRL/6199. This work made use of the data from FAST (Five-hundred-meter Aperture Spherical radio Telescope). FAST is a Chinese national mega-science facility, operated by National Astronomical Observatories, Chinese Academy of Sciences. We acknowledge the support of the staff of the Xinglong 85 cm telescope. This work was partially supported by the Open Project Program of the CAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences. We acknowledge the support of the staff of the Weihai 1 m telescope. We thank Lei Qian, Yang Gao, and Xingyao Chen for their advice in the application of the FAST observation project. We thank Julien Morin for providing information on the magnetic topology of AD Leo from recent ZDI measurements. Funding Information: We are grateful for the financial support from NSFC grants 12250006. P.Z. acknowledges funding from the ERC under the European Union's Horizon 2020 research and innovation program (grant agreement No. 101020459—Exoradio). C.K.L.'s work at the Dublin Institute for Advanced Studies was funded by the Science Foundation Ireland grant 18/FRL/6199. This work made use of the data from FAST (Five-hundred-meter Aperture Spherical radio Telescope). FAST is a Chinese national mega-science facility, operated by National Astronomical Observatories, Chinese Academy of Sciences. We acknowledge the support of the staff of the Xinglong 85 cm telescope. This work was partially supported by the Open Project Program of the CAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences. We acknowledge the support of the staff of the Weihai 1 m telescope. We thank Lei Qian, Yang Gao, and Xingyao Chen for their advice in the application of the FAST observation project. We thank Julien Morin for providing information on the magnetic topology of AD Leo from recent ZDI measurements. Publisher Copyright: {\textcopyright} 2023. The Author(s). Published by the American Astronomical Society.",
year = "2023",
month = aug,
day = "1",
doi = "10.3847/1538-4357/acdb77",
language = "English (US)",
volume = "953",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",
}