{
  "bibcode": "2023GCN.33611....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 2023-04-05 at 13:20:20.04 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin (GCN 33567). We observed the nearest gamma-ray source 4FGL J0802.0+1006 and the best-fit position of IceCube-230405A with BOOTES-4/MET robotic telescope.The magnitudes were calculated using bright stars in the same frame and the SDSS-DR16 as reference. We did not detect any optical source within the best-fit position, and also the optical counterparts of 4FGL J0802.0+1006. The upper limits of magnitudes (without being corrected for Galactic extinction) are given as follows. \n\nSources | Tmid-T0 (day) | UT (start) | Upper Limit (error) | Exposure Time | Filter \n\n--------------------------------------------------------------------------------------------------------------\n\nBest-fit position| 1.18 | 23-04-06 17:43:37.49 | 18.96 (0.06) | 300s | SDSS-i  \n\nJ0802.0+1006 | 1.2 | 23-04-06 18:08:52.38 | 18.69 (0.04) | 300s | SDSS-i\n\n-------------------------------------------------------------------------------------------------------------\n\nThe Burst Optical Observer and Transient Exploring System (BOOTES, bootes.iaa.es) is a completed world-wide network of robotic telescopes led at IAA-CSIC (Spain) which aims at following-up transients and other astrophysical sources in the sky for which the first station was installed in 1998 (Castro-Tirado et al. 1999). 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). See also Hu et al. (2021). We acknowledge the support of BOOTES-4 technical staffs.",
  "circularId": 33611,
  "createdOn": 1681487844000,
  "email": "xiongdingrong@ynao.ac.cn",
  "subject": "IceCube-230405A: BOOTES-4/MET Optical Upper Limits",
  "submitter": "Dingrong Xiong at Yunnan Observatories of CAS, China  <xiongdingrong@ynao.ac.cn>",
  "eventId": "IceCube-230405A"
}