GCN Circular 37207
Subject
GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
Date
2024-08-20T13:13:35Z (2 months ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Via
Web form
S.Q. Jiang, J. An (NAOC), S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), X. Liu, S.Y. Fu, 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 GRB 240819A detected by SVOM/Eclairs using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Fresno, California, US. Observations started at 09:41:45.015 UTC on 2024-08-19, i.e., 7.107 hr after the T0 of this GRB, and 16 x 240 s frames were obtained in R-band aiming to cover the whole SVOM/Eclairs error circle.
No new optical source is detected within the X-ray error circles provided by Swift/XRT (Evans et al., GCN37203) and EP/FXT (Li et al., GCN 37206), down to the following 3-sigma optical upper limits:
Source | R.A. | Dec. | Upper Limit (mag)
--------------------------------------------------------
XRT Source1 | 311.0531 | 49.6821 | R>19.0
XRT Source2* | 310.9468 | 49.5141 | N/A
EP J204334.6+493448 | 310.8943 | 49.5800 | R>19.8
EP J204347.6+493054* | 310.9483 | 49.5149 | N/A
EP J204244.0+494023 | 310.6835 | 49.6730 | R>19.8
calibrated with PanSTARRS stars in the field and not corrected for Galactic extinction. The two sources marked with * are very likely an identical one detected by both Swift/XRT and EP/FXT, but not covered by TRT.