TITLE: GCN CIRCULAR NUMBER: 38415 SUBJECT: EP241201a: EP detection of a fast X-ray transient DATE: 24/12/02 07:27:17 GMT FROM: EP Team at NAOC/CAS ep_ta@bao.ac.cn
W. Chen, T. Zhao(NAO,CAS), C. Zhou(HUST), G. Y. Zhao(SYSU), W. D. Zhang(NAO,CAS) report on behalf of the Einstein Probe team:
We report the detection of an X-ray transient EP241201a by EP-WXT, which triggered the on-board processing unit at 2024-12-01T21:01:22 (UTC) (trigger ID: 01709126276). We analysed the telemetry data of WXT, and found in the lightcurve a fast X-ray flare that started at 2024-12-01T20:59:16 (UTC) and lasted for about 230 seconds. The position is R.A. = 282.596 deg, DEC = 66.081 deg (J2000) with an uncertainty of about 2.343 arcmin (radius, 90% C.L. statistical and systematic). The average 0.5-4 keV spectrum that was extracted from the time interval of the flare can be fitted with an absorbed power law with a photon index of 3.9(-1.4,+1.6) and a column density of 1.5(-0.6,+0.8)e22 cm^-2. The unabsorbed flux in 0.5-4 keV is 7.1(-4.9,+32.7)e-9 erg/s/cm^2.
We plan to perform a target of opportunity observation with the Follow-up X-ray Telescope (FXT) on board EP. Further follow-up observations are encouraged to explore the orgin of EP241201a.
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).
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