GCN Circular 37829
Subject
GRB 241017A/sb24101702: Mephisto optical upper limit
Date
2024-10-20T03:57:27Z (4 days ago)
From
Brajesh Kumar at SWIFAR, YNU <brajesh@ynu.edu.cn>
Via
Web form
Xiangkun Liu (SWIFAR, YNU), Brajesh Kumar (SWIFAR, YNU), Guowang Du (SWIFAR, YNU), Kaushik Chatterjee (SWIFAR, YNU), Fanchuan Kong (SWIFAR, YNU), Yaosong Yu (SWIFAR, YNU), Xingzhu Zou (SWIFAR, YNU), Yu Pan (SWIFAR, YNU), Xinlei Chen (SWIFAR, YNU), Yuanpei Yang (SWIFAR, YNU), Yehao Cheng (SWIFAR, YNU), Jinghua Zhang (SWIFAR, YNU), Yuan Fang (SWIFAR, YNU), Xuhui Han (NAOC), Pinpin Zhang (NAOC), Liping Xin (NAOC), Chao Wu (NAOC), Xiaowei Liu (SWIFAR, YNU) report on behalf of the Mephisto Team:
We performed simultaneous multi-band photometric observations of GRB 241017A/sb24101702 (Le Provost et al., GCN 37799) with the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. The observations were initiated at 15:35:30 2024-10-17 UT (~11.6 hrs after SVOM/Eclairs trigger) and several frames were taken in uvgriz bands (although affected with high background due to the moon light). We did not find any uncatalogued source in the stacked images which is consistent with the results reported by Mohan et al. (GCN 37808), Bochenek et al. (GCN 37810) and Qiu et al. (GCN 37820). The 3-sigma limiting magnitudes are below:
Mid-Time (UT) Band Total-Exp (s) Lim-mag (AB)
2024-10-17T15:53:31 u 180s x 4 >21.07
2024-10-17T15:52:06 v 180s x 4 >21.70
2024-10-17T15:52:58 g 50s x 10 >19.89
2024-10-17T15:51:33 r 50s x 10 >22.14
2024-10-17T15:53:05 i 79s x 7 >20.09
2024-10-17T15:51:40 z 79s x 7 >19.48
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Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6m 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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