TITLE: GCN CIRCULAR NUMBER: 36471 SUBJECT: transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss DATE: 24/05/14 04:37:22 GMT FROM: wangbc@bao.ac.cn Y. M. Mao (NAOC), R. Wang (NAOC), B. C. Wang (NAOC), J. J. Jin (NAOC), L. Ge (NAOC), Z. Fan (NAOC), H. Wu (NAOC), J. Zheng (NAOC) report on behalf of Xinglong Nearby Galaxy Supernova Survey: We observed the field of the optical transient AT2024iss that was detected by GOTO, using a 10.6cm refraction telescope located at xinglong observatory, naoc. We obtained 9 x 120 s frames in both RGB bands, with a median time of 2024-05-12T14:35:20Z frames, i.e., 7 hr before the GOTO detection. The 7σ limiting magnitude of the stacked RGB images are 17.8, 18, and 18.2 mag, respectively. Photometry of the candidate and the field stars are obtained using SEP, and the RGB bands are calibrated using the r, V, and g band of the APASS catalog, respectively. The measured magnitudes are listed in the table below. We performed forced photometry on the data from 24h ago, and the results of the photometry in all bands were below the detection limit and no signal was detected. +-----------+---------------+--------+--------------------+ | ID | JD | filter | magnitude | +-----------+---------------+--------+--------------------+ | AT2024iss | 2460442.141 | g | >18.2 | | AT2024iss | 2460442.140 | V | >18.0 | | AT2024iss | 2460442.139 | r | >17.8 | | AT2024iss | 2460443.147 | g | 14.37 +/- 0.01 | | AT2024iss | 2460443.146 | V | 14.67 +/- 0.01 | | AT2024iss | 2460443.145 | r | 14.65 +/- 0.02 | +-----------+---------------+--------+--------------------+ Further observations are encouraged. View this GCN Circular online at https://gcn.nasa.gov/circulars/36471. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...