GCN Circular 41257
Subject
EP250802a: EP-FXT follow-up observation
Event
Date
2025-08-07T08:39:07Z (23 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
Y.-H. I. Yin (NJU), X. Mao, T. Zhao, C. C. Jin (NAO, CAS) on behalf of the Einstein Probe (EP) team:
EP-FXT performed a follow-up observation of EP250802a (GCN 41221) at 2025-08-04T04:10:31 (UTC), about 42 hours after the WXT detection, with an exposure time of 1.5 ks. The source was also followed by several optical telescopes (GCN 41222, GCN 41223, GCN 41224, GCN 41227). Three uncatalogued sources are detected within the WXT error circle, among which Source 1 is spatially consistent with a known star TYC 2158-1481-1. Preliminary analysis on these sources are automatically conducted, and the details are listed as follows.
Source 1: EPF_J201319.4+244937
RA (J2000): 303.3308
Dec (J2000): 24.8268
Flux: 4.63 x 10^-13 erg/s/cm^2 (observed, 0.5-10 keV)
Flux_err: 1.25 x 10^-13 erg/s/cm^2 (1 sigma)
Note: This source is spatially consistent with the a known star TYC 2158-1481-1.
Source 2: EPF_J201330.2+244901
RA (J2000): 303.3759
Dec (J2000): 24.8168
Flux: 2.21 x 10^-13 erg/s/cm^2 (observed, 0.5-10 keV)
Flux_err: 6.99 x 10^-14 erg/s/cm^2 (1 sigma)
Source 3: EPF_J201318.2+245121
RA (J2000): 303.3260
Dec (J2000): 24.8559
Flux: 3.56 x 10^-13 erg/s/cm^2 (observed, 0.5-10 keV)
Flux_err: 9.84 x 10^-14 erg/s/cm^2 (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).