GCN Circular 45543
Subject
GRB 260909A: EP-FXT follow-up observation
Event
Date
2026-09-10T01:38:50Z (5 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
X. Mao, Q. H. Lao (NAO, CAS), M. Y. Wang (XMU), L. N. Xu (USTC), S. Y. Fu, A. D. Zhu (HUST), H. H. Zhang (NJU), M. Nie (YNAO, CAS), X. H. Tang (THU), C. C. Jin (NAO,CAS) on behalf of the Einstein Probe (EP) team:
EP-FXT performed a follow-up observation of GRB 260909A, detected by SVOM/ECLAIRs (sb26090910; Saccardi et al., GCN 45534), SVOM/MXT (Saccardi et al., GCN 45534) and SVOM/GRM (Wang et al., GCN 45538), and observed in optical by COLIBRI (Guan et al., GCN 45535), Xinglong (Ma et al., GCN 45536), Mondy (Pankov et al., GCN 45537), SVOM/VT (Li et al. GCN 45539). The observation started at 2026-09-09 12:49:58 (UTC), about 1.53 hours after the SVOM/ECLAIRs trigger, with an exposure time of 6002 s.
On-ground analysis of the EP-FXT data found an uncataloged fading X-ray source within the SVOM/MXT error region (Pankov et al., GCN 45537). The preliminary results for the X-ray source are as follows:
Source name: EPF_J005208.3+241147
R.A., Decl. (J2000) = 13.0345, 24.1964 deg
Localization error radius = 10 arcsec
0.5-10 keV flux = 4.07e-12 erg/cm^ 2/s
Flux error = 2.48e-13 erg/cm^2/s (1 sigma)
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).