TITLE: GCN CIRCULAR NUMBER: 38275 SUBJECT: GRB 241030A: J-band observations DATE: 24/11/19 05:08:59 GMT FROM: dongzhn@mail2.sysu.edu.cn Zhong-Nan Dong, Yan Yu , Jia-Qi Lin, Si-Yuan Zhu, Wei-Sen Huang, Jin-Ji Li, Pu Lin, Hao-Nan Yang, Hao-Ran Zhang, Hui-Ying Deng, Pak-Hin Thomas Tam, Bin Ma (Sun Yat-sen University) report: The Sun Yat-sen University 80cm infrared telescope observed the field of GRB 241030A (Klingler et al., GCN 37956; Beardmore et al., GCN 37962; Wang et al., GCN 37972; Pillera et al., GCN 37979; Ridnaia et al., GCN 37982; Ambrosi et al., GCN 37988; Wu et al., GCN 37997; Adami et al., GCN 38041; Moskvitin & Goranskij, GCN 38016; Busmann et al., GCN 38019; Schneider et al., GCN 38021; Li et al., GCN 38027; Masi, GCN 38031; Moskvitin et al., GCN 38032, Yan et al., GCN 38035; Wang et al., GCN 38055; Pal et al., GCN 38074; Jayaraman et al., GCN 38134; Ankur et al., GCN 38220). Our observations began at 2024-10-30 13:50:49 UTC, 8.13 hours after the GRB trigger. We took 100 frames with 20s exposures in J band. The calculated position is RA = 343.1402°, Dec = +88.4499°, which corresponds to RA(J2000) = 22h 52m 33.7s, Dec(J2000) = +80° 26' 59.7". In our stacked images, we clearly detect the near-infrared transient. We observed a peak magnitude of 16.8 ± 0.1 Vega mag, followed by a decline of 1 mag over the next seven hours. We also observed the source on October 31, November 1, 3, 4, 5, and 9. However, in the stacked frames from these subsequent observations, we did not detect the source down to a 5-sigma depth of J ~ 18 Vega mag. View this GCN Circular online at https://gcn.nasa.gov/circulars/38275. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...