TITLE: GCN CIRCULAR NUMBER: 33164 SUBJECT: IceCube-230112A: BOOTES-4/MET Optical Upper Limit DATE: 23/01/13 08:05:07 GMT FROM: Dingrong Xiong at Yunnan Observatories of CAS, China 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: On 2023-01-12 at 06:44:50.60 UT (T0) IceCube detected a track-like event with a moderate probability of being of astrophysical origin (GCN 33161). We observed the best-fit position of IceCube-230112Awith BOOTES-4/MET 0.6m automatic optical telescope. The magnitude was calculated using three bright stars in the same frame and the SDSS DR16 catalogue as reference. We did not detect any optical source within the best-fit position. The upper limit of magnitude (without being corrected for Galactic extinction) is given as follows. Tmid-T0 (day) | UT (start) | 3-sigma Upper Limit (error) | Exposure Time | Filter -------------------------------------------------------------------------------------------------------------- 0.367 | 23-01-12T15:33:14.8 | 19.25 (0.06) | 6*180s (co-added) | Clear --------------------------------------------------------------------------------------------------------------- The 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.