TITLE:   GCN CIRCULAR
NUMBER:  33761
SUBJECT: GRB 230510A: Nanshan/NEXT optical afterglow detection
DATE:    23/05/11 03:06:34 GMT
FROM:    Dong Xu at NAOC/CAS <dxu@nao.cas.cn>

S.Q. Jiang, T.H. Lu, S.Y. Fu, X. Liu, D. Xu (NAOC), Z.P. Zhu (NAOC, HUST), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:

We observed the field of GRB 230510A detected by Swift (Eyles-Ferris et al., GCN 33752) and Fermi (Fermi GBM team, GCN 33751) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. Observations started at 18:47:49.1 UT on 2023-05-10, i.e., 6.69 hr after the Swift/BAT trigger, and 12x200 s exposures have been obtained in the Sloan r-filter.

We detected an uncatalogued optical transient (OT) within the enhanced Swift/XRT error circle (Evans et al., GCN 33756) at coordinates

R.A. (J2000) = 21:12:32.87
Dec.(J2000) = +34:26:35:59

with an uncertainty of ~ 0.5 arcsec, and it has m(r) = 20.5 +/- 0.1 mag in the co-added image at 7.27 hr post-burst, calibrated with the nearby PanSTAR field. PanSTAR covers this position and is much deeper, but the OT is not present. We thus conclude that the OT is the optical afterglow of the burst.