GCN Circular 38726
Subject
GRB 241229A: EP-FXT afterglow candidates
Date
2024-12-30T11:41:58Z (3 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
S.Q. Jiang, J. W. Hu, W. J. Zhang, X.P. Xu (NAO, CAS), W.F. Wen (SZTU), J. H. Wu (GU), H.W. Pan, Z.X. Ling (NAO, CAS), B. Cordier (CEA) on behalf of Einstein Probe teams:
We performed a follow-up observation of GRB 241229A (SVOM/ECLAIRs, Liang et al., GCN 38697) with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission. The observation started at 2024-12-29 14:11:35 (T-TGRB ~ 14.1 hr) for about 3 ks of exposure in total.
Three uncatalogued X-ray sources are detected by both FXT-A and FXT-B within the 7.6 arcmin error circle of SVOM/ECLAIRs (Liang et al., GCN 38697). We list the sources in the following table, with the seperations from the ECLAIRs source given. The observed 0.5-10 keV flux given in the table is a rough estimate assuming the same spectral paramters, and is not corrected for absorption.
| FXT source | R.A. (deg, J2000) | DEC (deg, J2000) | Sep. (arcmin) | Flux (erg/s/cm^2) |
| EPF_J125139.4+315311 | 192.9133 | 31.8867 | 2.06 | 6.82 x 10^(-14) |
| EPF_J125129.3+314453* | 192.8715 | 31.7484 | 6.61 | 7.73 x 10^(-13) |
| EPF_J125101.6+315007 | 192.7572 | 31.8356 | 7.04 | 9.25 x 10^(-14) |
* sources also detected by Swift/XRT (Evans et al., GCN 38711)
Further follow-up observation will be performed by the EP-FXT to confirm the afterglow of GRB 241229A.
The above observation was made with the EP-FXT instrument. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES.