{
  "bibcode": "2021GCN.29392....1L",
  "body": "C. Y. Li, S. L. Xiong, S. Xiao, C. Cai, Y. Huang, Y. Zhao, J. C. Liu,\nJ. J. He, Q. B. Yi, B. X. Zhang, Y. Q. Zhang, S. Y. Zhao, C. Zheng,\nZ. H. An, C. Chen, G. Chen, W. Chen, M. Gao, K. Gong, D. Y. Guo, B. Li,\nC. Li, J. H. Li, Q. X. Li, X. B. Li, X. Q. Li, Y. G. Li, X. H. Liang,\nJ. Y. Liao, J. C. Liu, X. J. Liu, Y. Q. Liu, F. J. Lu, Q. Luo, X. Ma,\nG. Ou, W. X. Peng, R. Qiao, D. L. Shi, J. Y. Shi, L. M. Song,\nX. Y. Song, G. X. Sun, X. L. Sun, Y. L. Tuo, C. W. Wang, J. Z. Wang,\nP. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, W. C. Xue, S. Yang, M. Yao,\nC. Y. Zhang,D. L. Zhang, Fan Zhang, Fei Zhang, H. M. Zhang, K. Zhang,\nP. Zhang, S. N. Zhang, Z. Zhang, X. Y. Zhao, S. J. Zheng, X. Zhou (IHEP),\nreport on behalf of GECAM team:\n\nDuring the commissioning phase, GECAM-B in-flight triggered (Trig#\n66119400) a long burst, GRB 210204A, at 2021-02-04T06:30:00.600 UTC (T0),\nwhich was also reported by Fermi/GBM (GCN 29390) and\nCALET/CGBM (Trig# 1296455384).\n\nGECAM alert data was promptly downlinked to the ground through the\nshort message service of BeiDou Navigation Satellite System (BDS).\nThe time latency of the first BeiDou message relative to the trigger time\nis about 1 minute.\n\nAccording to the BDS alert data, this burst mainly consists of\nmultiple pulses, while the later bright pulse is evident in the alert data\nalthough it falls in the last wide time bin.\nThe burst spectrum extends above about 400 keV.\n\nAn automatic on-ground localization was calculated using the light curves\nand spectrum in the alert data.\nAlthough the in-flight calibration of energy response and\nlocalization has not been finalized yet, GECAM-B localized this burst to\nthe following position (J2000):\nRa: 121.7 deg�� Dec: 1.5 deg\nErr: 7.5 deg (1-sigma, statistical only)\nThe current systematic error of location is estimated to be several degrees\nwhich could be minimized by the ongoing calibration.\n\nThe GECAM-B location is consistent with the Fermi/GBM position (GCN 29390,\n29391) within error.\n\nThe GECAM light curve could be found here:\nhttp://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_lc_grd_all_combine_66119400.png\n\nThe GECAM preliminary on-ground location could be found here:\nhttp://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_skymap_bdm_66119400_V01.png\n\nAs the detailed science data are downloaded, all analyses would be improved.\n\nPlease note that all GECAM results here are preliminary. The final analysis\nwill be published in journal papers or GECAM online catalog.\n\nGravitational wave high-energy Electromagnetic Counterpart All-sky Monitor\n(GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in\nLow Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time),\nwhich was funded by the Chinese Academy of Sciences (CAS).",
  "circularId": 29392,
  "createdOn": 1612425118000,
  "email": "xiongsl@ihep.ac.cn",
  "subject": "GRB 210204A: GECAM detection",
  "submitter": "Shaolin Xiong at IHEP  <xiongsl@ihep.ac.cn>",
  "eventId": "GRB 210204A"
}