TITLE:   GCN CIRCULAR
NUMBER:  46226
SUBJECT: EP261111a: Einstein Probe detection of an X-ray transient
DATE:    26/11/11 14:03:15 GMT
FROM:    EP Team at NAOC/CAS <ep_ta@bao.ac.cn>

G. L. Huang, Z. X. Li (IHEP, CAS), Y. J. Zhang (THU), W. D. Zhang (NAO, CAS) on behalf of the Einstein Probe (EP) team:

We report on the detection of an X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP261111a. The transient triggered EP-WXT (ID: 01709322401) at 2026-11-11T13:25:10 (UTC). The WXT position of the source is R.A. = 43.118 deg, DEC = 44.444 deg (J2000) with an uncertainty of 3 arcmin in radius (90% C.L. statistical and systematic).

A follow-up observation with the Follow-up X-ray Telescope (FXT) was performed automatically. Within the WXT error circle, an uncatalogued X-ray source was detected at R.A. = 43.1202 deg, DEC = 44.4365 deg (J2000) with an uncertainty of 20 arcsec in radius (90% C.L. statistical and systematic).

Further information will be updated when the telemetry data is received.

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).