GCN Circular 38339
Subject
EP241126a: EP-FXT follow-up observation update
Date
2024-11-27T09:51:05Z (a month ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
T. C. Zheng, D. F. Hu (PMO, CAS), B.-T. Wang (YNAO, CAS), M. J. Liu, H. Q. Cheng, C. C. Jin (NAO, CAS) on behalf of the Einstein Probe team
Following the detection of the fast X-ray transient EP241126a (Hu et al., GCN 38335), we performed an observation of EP241126a with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe. The observation started at 2024-11-27T03:08:53 (UTC), about 7.5 hours after the EP-WXT detection, with an exposure time of 2980 seconds. An uncatalogued X-ray source is detected at R.A. = 33.7444 deg, DEC = 11.7013 deg (J2000) with an uncertainty of 10 arcsec in radius (90% C.L. statistical and systematic). The average FXT spectrum in 0.5-10 keV band can be fitted by an absorbed power law with a photon index of 2.2(+0.7/-0.7) (with a column density fixed at the Galactic one of 7.4 x 10^20 cm^-2), giving an average unabsorbed flux of 1.3(+1.1/-0.5) x 10^(-13) erg/s/cm^2 in the 0.5-10 keV band. The FXT position is ~10 arcsec away from the likely optical counterpart detected by TRT (Fu et al., GCN 38337) and LCO (Li et al. GCN 38338). We thus suggest the FXT detection being associated with EP241126a.
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).