GCN Circular 43465
Subject
EP260119a: update of EP-FXT follow-up observation
Event
Date
2026-01-20T03:17:16Z (4 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
Y. H. Jiang (NJU), D. Zhu, K.J. Zhang ,Y.H. Cheng (SWIFAR,YNU), R. X. Hu (WHU)，H. Sun (NAO, CAS) on behalf of the Einstein Probe (EP) team:
EP-FXT performed a follow-up observation of EP260119a (detected by EP-WXT, GCN #43447; and followed by COLIBRI telescope, LCO telescope, MASTER-Net observations, SAO RAS and NOT; GCN #43450, GCN #43455, GCN #43452, GCN #43454, GCN #43463, GCN #43464) about 7.5 hours after the WXT detection, with an exposure time of 6.0 ks. The FXT telemetry data show that an uncatalogued source was detected within the WXT error circle at R.A. = 158.1047, DEC = 65.4975 (J2000) with an uncertainty of 10 arcsec (radius, 90% C.L. statistical and systematic, reported by Cheng et al ., GCN #43449). The FXT X-ray spectrum of this uncatalogued source can be fitted with an absorbed powerlaw with a hydrogen column density fixed at the Galactic value of 1.20 x 10^20 cm^-2 and a photon index of 1.99 (+/- 0.13). The derived unabsorbed 0.5-10 keV flux is approximately 5.69 (+0.60/-0.55) x 10^-13 erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters.
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).