GCN Circular 41199
Subject
GRB 250727A: EP-FXT follow-up observation
Event
Date
2025-07-30T06:15:15Z (20 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
Y.-H. I. Yin (NJU), R. D. Liang, W. Yuan (NAO, CAS) on behalf of the Einstein Probe (EP) team:
EP-FXT performed a follow-up observation of the SVOM/ECLAIRs-detected burst GRB 250727A (SVOM/sb25072701) (Cao et al. GCN 41176) at 2025-07-29T10:57:54 (UTC), about 48 hours after the SVOM/ECLAIRs trigger, with an exposure time of 3878s. Three FXT candidate sources (Yin et al. GCN 41182) are not detected in this observation. The upper limits are listed as follows.
Source 1: EPF_J234436.3-810410
RA (J2000): 356.1514
Dec (J2000): -81.0694
Flux upper limit: 8.78 x 10^-14 erg/s/cm2 (0.5-10 keV)
Source 2: EPF_J234357.8-811244
RA (J2000): 355.9909
Dec (J2000): -81.2121
Flux upper limit: 1.03 x 10^-13 erg/s/cm2 (0.5-10 keV)
Source 3: EPF_J234541.4-811245
RA (J2000): 356.4225
Dec (J2000): -81.2124
Flux upper limit: 6.40 x 10^-14 erg/s/cm2 (0.5-10 keV)
Note: This source is spatially consistent with the candidate counterpart Source 1 (SWIFT J234539.1-811248) detected by Swift/XRT.
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).