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GCN Circular 33084

IceCube-221210A: BOOTES-4/MET and Lijiang 2.4-meter Telescopes Optical Observations
2022-12-19T15:43:34Z (a year ago)
Dingrong Xiong at Yunnan Observatories of CAS, China <>
D. R. Xiong, J. M. Bai, Y. F. Fan, H. C. Feng, 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 BOOTESteam and Lijiang 2.4-meter team report:


On 22-12-10 at 08:35:11.23 UT (T0) IceCube detected a track-like event with a moderate probability of being of astrophysical origin (GCN 33040). The two gamma-ray sources 4FGL J2207.1+2222 (blazar candidate) and 4FGL J2212.0+2356 (flat-spectrum radio quasar) in 4FGL-DR3, closest from best-fit position, are located in the 90% uncertainty contour, and are located 0.82 and 1.25 deg away from the best-fit position, respectively (GCN 33040; GCN 33075).


We observed the gamma-ray source 4FGL J2207.1+2222 using BOOTES-4/MET 0.6m automatic optical telescope on 22-12-12 at 13:03:03.88 UT. There was no optical source within localizationof the gamma ray source. The upper limit of AB magnitude (without being corrected for Galactic extinction) is 17.72 +/- 0.01 (clear filter, exposure of 17*60s). 


The gamma-ray source 4FGL J2212.0+2356 was observed using BOOTES-4/MET 0.6m automatic optical telescope and Lijiang 2.4-meter optical telescope. After correcting flat field and bias, we used PyRAF to implement aperture photometry. The magnitudes were calculated using four stars in the same frame and the SDSS DR16 catalogue as reference. The magnitudes (without being corrected for Galactic extinction) are given as follows. 


MJD-T0 (day) | UT(Start) | Magnitudes (mag) | Exposure Time | Filter | Telescope 


1.117 | 22-12-11T11:23:20.72 | 18.003 (0.06) | 400s | SDSS-i | Lijiang 2.4-meter


1.152| 22-12-11T12:13:49.41 | 18.35 (0.09) | 3*180s | Clear | BOOTES-4


2.130| 22-12-12T11:42:05.74 | 18.681 (0.082) | 30*60s | Clear | BOOTES-4



The above magnitude values are smaller than that in DR16 (SDSS-i: 19.3 mag), i.e., during our observation period, this target becomes brighter in optical band. 


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 BOOTE Network, BOOTES-4/MET, is located at the Lijiang Observatory of the Yunnan Observatories of China (Xiong et al. 2020). The Lijiang 2.4-meter Telescope (LJT), the largest common-purpose optical telescope in China. It is located at the Gaomeigu site, Lijiang Observatory, in the southwest of China (Wang et al. 2019).

We acknowledge the support of these staffs from the BOOTES telescope networks and Lijiang 2.4-meter telescope.
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