{
  "bibcode": "2022GCN.33102....1X",
  "body": "D. R. Xiong, J. M. Bai, Y. F. Fan, K. Ye, C. J. Wang, Y. X. Xin, B. L. Lun, J. R. Mao, X. H. Zhao, L. Xu, X. G. Yu, K. X. Lu, X. Ding, D. Q. Wang (Yunnan Observatories), A. J. Castro-Tirado, E. Fernandez-Garcia, Y. D. Hu (IAA-CSIC) and C. J. Perez del Pulgar (UMA) on behalf of the BOOTES team report:\n\nOn 22-12-24 at 00:55:09.3 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin. The nearest gamma-ray source 4FGL J2223.3+0102 is 0.39 deg away from the best-fit event position, but without localization of 90% uncertainty region of the event (GCN 33097).\n\nWe observed the best-fit position of IceCube-221224A and the gamma-ray source 4FGL J2223.3+0102 with BOOTES-4/MET 0.6m automatic optical telescope. We did not detect any optical source within localizations of both them. The upper limits of magnitudes (without being corrected for Galactic extinction) are given as follows. \n\nName | UT (start) | Upper Limits (3-sigma) | Exposure Time | Filter \n\n--------------------------------------------------------------------------------------------------------------\n\nBest-fit position ofIceCube-221224A | 22-12-24T11:36:39.25 | 18.90 (0.05) | 5*60s | Clear \n\n4FGL J2223.3+0102| 2022-11-24T12:06:12.63 | 18.20 (0.04) | 10*60s | SDSS-i  \n\n---------------------------------------------------------------------------------------------------------------\n\nThe Burst Optical Observer and Transient Exploring System (BOOTES) is a world-wide automatic telescope network which aims to repaid follow-up of transient and astrophysical sources in the sky for which the first station was installed in 1998 (Hu et al. 2021). The fourth station of the BOOTES Network, BOOTES-4/MET, is located at the Lijiang Observatory of the Yunnan Observatories of China (Xiong et al. 2020). We acknowledge the support of these staffs from the BOOTES telescope networks.",
  "circularId": 33102,
  "createdOn": 1671985917000,
  "email": "xiongdingrong@ynao.ac.cn",
  "subject": "IceCube-221224A: BOOTES-4/MET Optical Upper Limit",
  "submitter": "Dingrong Xiong at Yunnan Observatories of CAS, China  <xiongdingrong@ynao.ac.cn>",
  "eventId": "IceCube-221224A"
}