The Potential of Detecting Radio-flaring Ultracool Dwarfs at L band in the FAST Drift-scan Survey

作     者：Jing Tang Chao-Wei Tsai Di Li Jing Tang;Chao-Wei Tsai;Di Li

作者机构：CAS Key Laboratory of FASTNational Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China University of Chinese Academy of SciencesBeijing 100049China NAOC-UKZN Computational Astrophysics CentreUniversity of Kwa Zulu-NatalDurban 4000South Africa 

出 版 物：《Research in Astronomy and Astrophysics》 (天文和天体物理学研究（英文版）)

年 卷 期：2022年第22卷第6期

页      面：126-141页

核心收录：

学科分类：07[理学] 070401[理学-天体物理] 0704[理学-天文学] 

基　　金：supported by the National Natural Science Foundation of China grant Nos. 11988101, 11725313, 11690024, and 11703039 by the International Partnership Program of Chinese Academy of Sciences grant No. 114A11KYSB20160008 by the CAS Strategic Priority Research No. XDB23000000 FAST is operated by the Open Project Program of the Key Laboratory of FAST, Chinese Academy of Sciences 

主　　题：surveys-(stars:)brown dwarfs-stars flare-stars low-mass-stars magnetic field-radio continuum stars 

摘      要：The Five-hundred-meter Aperture Spherical radio Telescope(FAST)completed its commissioning and began the Commensal Radio Astronomy Fas T Survey(CRAFTS),a multi-year survey to cover 60%of the sky,in *** present predictions for the number of radio-flaring ultracool dwarfs(UCDs)that are likely to be detected by *** on the observed flaring UCDs from a number of unbiased,targeted radio surveys in the literature,we derive a detection rate of≥3%.Assuming a flat radio spectrumνLν∝ν^(β+1) withβ=-1.0 for UCD flares,we construct a flare luminosity function dN/dL∝L^(-1.96±0.45)(here L=νLν).CRAFTS is found to be sensitive enough for flares from UCDs up to~180 *** the Galactic thin disk,we carry out a 3D Monte Carlo simulation of the UCD population,which is then fed to mock CRAFTS *** estimate that~170 flaring UCDs would be detected through transient searches in circular *** only marginally sensitive to the scale height of UCDs,the results are very sensitive to the assumed spectral indexβ.Forβfrom 0 to-2.5,the number of expected detections increases dramatically from~20 to~*** also contemplate the strategies for following up candidates of flaring UCDs,and discuss the implications of survey results for improving our knowledge of UCD behavior at L band and dynamos.