GCN Circular 33351
Subject
IceCube-230217A: BOOTES-4/MET Optical Observations
Date
2023-02-19T17:09:55Z (a year ago)
From
Dingrong Xiong at Yunnan Observatories of CAS, China <xiongdingrong@ynao.ac.cn>
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 2023-02-17 at 20:49:43.4 UT (T0) IceCube detected a track-like event with a moderate probability of being of astrophysical origin. Two gamma-ray sources (4FGL J0816.9+2050 and 4FGL J0817.1+1955) listed in the 4FGL-DR3 Fermi-LAT catalog are located within the 90% error region of the candidate neutrino event (GCN 33337).
We observed the two gamma-ray sources and the best-fit position of IceCube-230217A with BOOTES-4/MET robotic telescope.The magnitudes were calculated using 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 and also not for the gamma-ray source 4FGL J0817.1+1955. The upper limits of magnitudes (without being corrected for Galactic extinction) are given as follows.
Sources | Tmid-T0 (day) | UT (start) | Upper Limit (error) | Exposure Time | Filter
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Best-fit position| 0.797 | 23-02-18 15:57:25.28 | 19.96 (0.11) | 2*350s (co-added) | Clear
J0817.1+1955 | 0.725 | 23-02-18 14:14:38.47 | 19.44 (0.07) | 350s | Clear
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0.674 days after T0, the magnitude value of 4FGL J0816.9+2050 in SDSS-r band is 18.055+/-0.17 (without being corrected for Galactic extinction). Compared with the magnitude value of SDSS-DR16, the target is not brightening during our observation period.
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The 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.