GCN Circular 39536
Subject
EP250227a: TRT optical upper limit
Date
2025-02-28T17:28:36Z (25 days ago)
From
sqjiang at NAOC <sqjiang@bao.ac.cn>
Via
Web form
S.Q. Jiang (NAOC), S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), J. An, X. Liu, S.Y. Fu, Z.P. Zhu, D. Xu, Z. Fan, W.X. Li, Y.N. Wang, N.C. Sun (NAOC) report on behalf of a large collaboration:
We observed the field of EP250227a detected by EP (Wen et al., GCN 39532), using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Cerro Tololo Inter-American Observatory, Chile. Observations started at 04:10:11.093 UT on 2025-02-28, i.e., 0.98 days after the EP trigger, and a series of 300 s frames were obtained in the R band.
No uncatalogued optical source is detected in the stacked R-band image within the EP/FXT error circle (Wen et al., GCN 39532), down to the 5-sigma limiting magnitude of R ~ 22.1, calibrated with LS-DR10 stars and not corrected for Galactic extinction, being consistent with the non-detections by NOT (Malesani et al., GCN 39533) and SLT (Aryan et al., GCN 39534).