TITLE: GCN CIRCULAR NUMBER: 38635 SUBJECT: GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits DATE: 24/12/19 14:52:37 GMT FROM: Brajesh Kumar at SWIFAR, YNU brajesh@ynu.edu.cn
Xiangkun Liu, Yu Pan, Dezi Liu, Brajesh Kumar, Xianao Wang, Chenxi Shang, Xufeng Zhu, Xingzhu Zou, Xinlei Chen, Yuanpei Yang, Yehao Cheng, Tao Wang, Guowang Du, Yuan Fang, Jinghua Zhang (all SWIFAR, YNU), Xuhui Han, Pinpin Zhang, Liping Xin, Chao Wu (all NAOC), Xiaowei Liu (SWIFAR, YNU) report on behalf of the Mephisto Team:
The field of GRB 241217A/EP241217B detected by SVOM/ECLAIRs (GCN 38594) and Einstein Probe (GCN 38606) was observed with the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. Simultaneous uvgriz band photometric observations were conducted starting from 17:09:14 2024/12/17 UT (~12 min after the SVOM/ECLAIRs trigger) and multiple frames with different exposure times were taken. We do not detect any uncatalogued sources in the stacked images within the SVOM/ECLAIRs error region and the 3 sigma upper limits are below.
UT start band Exp LimMag (AB) 2024/12/17/T17:09:14 u 300s*3 >21.6 2024/12/17/T17:09:14 g 300s*2, 50s*3 >21.6 2024/12/17/T17:09:14 i 300s*2, 79s*2 >20.6 2024/12/17/T17:13:48 v 300s*3 >21.0 2024/12/17/T17:13:48 r 300s*2, 50s*3 >21.6 2024/12/17/T17:13:48 z 300s*2, 79s*2 >20.3 ------------------------------------------------------------------------------------------------- Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6-m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The on-site telescope assemblage and commissioning were carried out in September 2022. The first light in all three channels was achieved on 2023 December 21. -------------------------------------------------------------------------------------------------
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