Multi-band optical monitoring of AT 2025dys/ATLAS25cof
ATel #17073; Jinghua Zhang (SWIFAR, YNU), Shiyan Zhong (SWIFAR, YNU), Guowang Du (SWIFAR, YNU), Bing Yan (SWIFAR, YNU), Xin Chang (SWIFAR, YNU), Brajesh Kumar (SWIFAR, YNU), Yuan Fang (SWIFAR, YNU), Xinlei Chen (SWIFAR, YNU), Xingzhu Zou (SWIFAR, YNU), Yu Pan (SWIFAR, YNU), Helong Guo (SWIFAR, YNU), Ningchen Sun (UCAS), Xiangkun Liu (SWIFAR, YNU), Xiaowei Liu (SWIFAR, YNU)
on 10 Mar 2025; 18:34 UT
Credential Certification: Brajesh Kumar (brajesh@ynu.edu.cn)
Subjects: Optical, Supernovae, Transient
We report the optical followup observations of AT 2025dys/ATLAS25cof (TNS Astronomical Transient Report No. 247536 and TNS AstroNote 2025-83) discovered by ATLAS group in galaxy 2MASX J10502184-2219183. The 50 cm array facilities and 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang observatory were triggered for multi band observations. These observations were started at 14:41:57 and 14:43:52 UTC on 2025-03-10 under moderate sky conditions with 50 cm array and Mephisto, respectively. Multiple frames were obtained across uvgr bands (with Mephisto) and iz bands (with 50 cm array). The SN candidate is clearly detected in each frame of uvgr bands while no evident detection is noticed in iz bands. The preliminary photometry of the initial frames is below (2025/01/01T14:43:52, u, 300s*1, 18.41 +/- 0.18; 2025/01/01T14:43:53, g, 150s*1, 18.47 +/- 0.11; 2025/01/01T15:02:56, v, 300s*1, 18.39 +/- 0.14; 2025/01/01T15:02:57, r, 150s*1, 18.51+/- 0.11; 2025/01/01T14:41:59, i, 300s*2, >19.31; 2025/01/01T14:41:57, z, 300s*2 >17.84). Further observations are planned. 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.
