GCN Circular 38330
Subject
GRB 241113B: EP-FXT afterglow detection
Date
2024-11-26T17:27:56Z (a month ago)
From
Damien Turpin at CEA-Saclay <dturpin-astro@hotmail.com>
Via
Web form
D. Turpin (CEA), Y.-H. I. Yin (NJU), T. Y. Lian (NAOC, CAS), Z. Y. Liu, M. Q. Huang (USTC), H. W. Pan, W. Yuan (NAOC, CAS), D. Adrien, C. Plasse (CEA/irfu), J. Guan, C. K. Li, Y . Chen, S. M. Jia, W. W. Cui, D. W. Han, W. Li, C. Z. Liu, F . J. Lu, L. M. Song, J. Wang, J. J. Xu, J. Zhang, S. N. Zhang, H. S. Zhao, X. F . Zhao (IHEP , CAS), Y . Liu, C. C. Jin, C. Zhang, Z. X. Ling, J. Wang, L. P . Xin (NAOC,CAS), E. Kuulkers, A. Santovincenzo (ESA), P . O'Brien (Univ. of Leicester), K. Nandra, A. Rau (MPE), B. Cordier (CEA) on behalf of the SVOM and Einstein Probe teams
We performed a follow-up observation of GRB 241113B (SVOM/ECLAIRs, Dagoneau et al., GCN 38196; SVOM/GRM, Liu et al., GCN 38212; EP/WXT, Liu et al. GCN 38214) with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission. The observation started at 2024-11-13T15:43:11 (T-TGRB ~ 4.3hr) for about 3ks of exposure in total.
An uncatalogued X-ray source is detected by both FXT-A and FXT-B at the position (J2000)
RA, DEC = 110.2396, 46.787 (error=10", 90% C.L.), 1.09 arcminute away from the SVOM/ECLAIRs position (Dagoneau et al., GCN 38196). This position is also consistent with the optical afterglow detected by KAIT (Zheng et al., GCN 38232) and SVOM/VT (Qiu et al., GCN 38306).
A preliminary analysis shows that the spectrum can be fitted with an absorbed power law with nH=0.72*10^21 cm^-2 and the photon index of 2.11. The observed flux in the 0.5-10.0 keV is 1.7(-0.4/+0.4)*10^-13 erg/s/cm^2.
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.