GCN Circular 45958

Z. -X. Li, G. -L. Huang (IHEP), R. -Z. Li (YNAO), M. Nie (YNAO) and H. Sun (NAOC) on behalf of the Einstein Probe (EP) team:
 
We report on the detection of an X-ray transient, designated EP261015b, by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission. The transient was detected by EP-WXT during an observation starting from 2026-10-15T13:56:38 (UTC), and identified by ground-based telemetry analysis. The WXT position of the source is R.A. = 0.581 deg, DEC = 30.973 deg (J2000) with an uncertainty of 2.83 arcmin in radius (90% C.L. statistical and systematic). No cataloged X-ray sources have been found within the WXT error circle. 

The average WXT 0.5-4 keV spectrum can be fitted by an absorbed power-law model with a Galactic hydrogen column density of 4.83e20 cm^-2 and a photon index of 2.11 (-0.81/+0.96). The derived average unabsorbed 0.5-4 keV flux is 3.50 (-1.27/+2.03) e-11 erg cm^-2 s^-1. All uncertainties are reported in 90% C.L.
 
We have arranged a follow-up observation with the Follow-up X-ray Telescope onboard EP and will update the information upon receiving the data. Multi-wavelength observations are strongly encouraged.
 
Launched on 2024 January 9, Einstein Probe is a space-based X-ray observatory designed to monitor the dynamic X-ray sky and perform rapid follow-up observations of newly discovered transients (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics).