{
  "createdOn": 1780492913313,
  "body": "J. W. Hu (NAO, CAS), Z. X. Li, G. L. Huang, J. Y. Cao (IHEP, CAS), Y. Liu (NAO, CAS) on behalf of the Einstein Probe (EP) team:\n\nThe X-ray transient EP260602b was detected by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission (Hu et al., GCN 44786) at 2026-06-02T17:53:12 (UTC). \n\nFollow-up observation by the Follow-up X-ray Telescope (FXT) on board EP was performed at 2026-06-03T04:30:31(UTC), ~10.5 hours after the WXT detection. The exposure time of the observation is around 4 ks. The on-ground analysis of the FXT data found an uncatalogued source at R.A. = 273.4737 deg, DEC = 7.5702 deg (J2000) with an uncertainty of 10 arcsec (radius, 90% C.L. statistical and systematic), which is consistent with the position of the optical counterpart (He et al., GCN 44780). The average FXT 0.5-10 keV spectrum can be fitted with an absorbed power law with a fixed Galactic hydrogen column density of 1.9×10^21 cm^-2, and a photon index of 2.0 (-0.7, +0.8). The derived average unabsorbed 0.5-10 keV flux is 1.4 (-0.6, +1.1)×10^(-13) erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters. \n\nLaunched 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).",
  "circularId": 44802,
  "submittedHow": "web",
  "submitter": "EP Team at NAOC/CAS <ep_ta@bao.ac.cn>",
  "subject": "EP260602b: EP-FXT follow-up observation",
  "eventId": "EP260602b",
  "format": "text/plain"
}