GCN Circular 45587
Subject
GRB 260915A: EP-FXT follow-up observation
Event
Date
2026-09-15T14:28:31Z (4 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
R.Shi, Y. F. Liang, J. Y. Liu (PMO, CAS), Y. Q. Zhao (PRIC, USTC), F. F. Song (YNAO, CAS), C. C. Jin (NAO, CAS) on behalf of the Einstein Probe (EP) team:
EP-FXT performed a follow-up observation of GRB 260915A, detected by SVOM/ECLAIRs and SVOM/GRM (sb26091501; Liang et al., GCN 45570), which was also observed in optical (Yin et al., GCN 45573; Wu et al., GCN 45575; Li et al., GCN 45581; Ducoin et al., GCN 45580; Zhu et al., GCN 45577; Perez-Garcia et al., GCN 45578). The observation started at 2026-09-15 02:51:49 (UTC), about 1.66 hours after the SVOM/ECLAIRs trigger, with an exposure time of 5195 s.
On-ground analysis of the EP-FXT data found two uncataloged X-ray sources within the SVOM/ECLAIRs error region (Liang et al., GCN 45570). Both show no clear decay. The preliminary results for the X-ray sources are as follows:
Source 1: EPF_J003237.9+081455
R.A., Decl. (J2000) = 8.1577, 8.2486 deg
Localization error radius = 10 arcsec
0.5-10 keV flux = 7.80e-12 erg/cm^ 2/s
Flux error = 4.12e-13 erg/cm^2/s (1 sigma)
Separation = 1.72 arcmin
Source 2: EPF_J003224.9+081259
R.A., Decl. (J2000) = 8.1037, 8.2161 deg
Localization error radius = 10 arcsec
0.5-10 keV flux = 5.43e-13 erg/cm^ 2/s
Flux error = 1.37e-13 erg/cm^2/s (1 sigma)
Separation = 2.20 arcmin
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).