TITLE: GCN CIRCULAR NUMBER: 33270 SUBJECT: IceCube-230201A: BOOTES-4/MET Optical Upper Limits DATE: 23/02/05 07:57:38 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 2023-02-01 at 06:20:54.42 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin. Three gamma-ray sources (4FGL J2256.7+1307, 4FGL J2308.9+1111 and 4FGL J2252.6+1245) listed in the 4FGL Fermi-LAT catalog are located within the 90% containment region (GCN 33244, 33248). We observed the three gamma-ray sources and the best-fit position of IceCube-230201A with BOOTES-4/MET robotic telescope.The magnitude was calculated using bright stars in the same frame and the Pan-STARRS catalogue as reference. We did not detect any optical source within the best-fit position, and also the optical counterparts of the three gamma-ray sources The upper limits of magnitudes (without being corrected for Galactic extinction) are given as follows. Source | Tmid-T0 (day) | UT (start) | Upper Limit (error) | Exposure Time | Filter -------------------------------------------------------------------------------------------------------------- Best-fit position| 2.274 | 23-02-03 12:55:15.82 | 19.3 (0.07) | 6*300s (co-added) | Clear J2256.7+1307 | 1.236 | 23-02-02 12:00:06.45 | 17.67 (0.16) | 2*300s (co-added) | Clear J2308.9+1111| 1.273 | 23-02-02 12:53:51.65 | 19.748 (0.04) | 2*300s (co-added) | Clear J2252.6+1245 | 1.286 | 23-02-02 13:13:22.89 | 19.06 (0.06) | 2*300s (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.