GCN Circular 43751
Subject
EP260214a: refined analysis of the EP-FXT observation
Event
Date
2026-02-15T13:22:15Z (a day ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
A. Li (BNU), J. Yang (ZZU), Y. H. Jiang (NJU), Y. Liu (NAOC) on behalf of the Einstein Probe (EP) team:
The fast X-ray transient EP260214a triggered the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission (Li et al., GCN 43742). It was followed by Global MASTER-Net (Lipunov et al., GCN 43743) and SVOM-VT (Li et al., GCN 43746). The refined analysis of the WXT data shows that the event started at T0=2026-02-14T20:37:00 (UTC), and lasted for approximately 60 seconds. The average WXT 0.5-4 keV spectrum can be fitted with an absorbed power law with a fixed Galactic hydrogen column density of 4.6×10^20 cm^-2 and a photon index of 0.8 (-0.6/+0.7). The derived average unabsorbed 0.5-4 keV flux is 9.7 (-0.3/+0.4) × 10^(-11) erg/s/cm^2.
The autonomous observation by the Follow-up X-ray Telescope (FXT) was performed at 2026-02-14T20:39:31 (UTC), 2.5 minutes after T0. The effective exposure time of the observation is around 3.3 ks. On-ground analysis of the FXT data found an uncatalogued source at R.A. = 201.2305, DEC = -29.0431 (J2000) with an uncertainty of 10 arcsec in radius (90% C.L. statistical and systematic). The average 0.5-10 keV spectrum can be fitted with an absorbed power law with a fixed Galactic hydrogen column density of 1.6 × 10^20 cm^-2, and a photon index of 2.3 (-0.3/+0.3). The derived average unabsorbed 0.5-10 keV flux is 1.4 (-0.1/+0.2) ×10^(-11) erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters.
Further FXT follow-up observations have been arranged.
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).