TITLE:   GCN CIRCULAR
NUMBER:  37434
SUBJECT: EP240908a: TRT optical upper limit
DATE:    24/09/09 11:34:12 GMT
FROM:    Dong Xu at NAOC/CAS <dxu@nao.cas.cn>

S.Y. Fu, S.Q. Jiang (NAOC), S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), X. Liu, J. An, Z.P. Zhu, S.Y. Gao, D. Xu, Z. Fan, W.X. Li, N.C. Sun, Y.N. Wang (NAOC) report on behalf of a large collaboration:

We observed the field of EP240908a (Mao et al., GCN 37432) using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Sierra Remote Observatories, USA. Observations started at 07:27:05.3 UTC on 2024-09-09, and 6 x 300 s  frames in R-band were obtained.

No new optical source is detected in the stacked image within or beside the ~ 10-arcsec EP/FXT error circle (Mao et al., GCN 37432), down to a 5-sigma limiting magnitude of R ~ 21.6, calibrated with PanSTARRS sources in the field and not corrected for Galactic extinction.