GCN Circular 37669

X. Mao (NAOC, CAS), R.-Z. Li (YNAO, CAS), Y.-H. I. Yin (NJU), X. Tian (GXU), H. L. Peng (NNU), H. W. Pan, W. Yuan, C. C. Jin, H. Y. Liu, Y. Liu, Z. X. Ling, C. Zhang, H. Q. Cheng, W. Chen, C. Z. Cui, D. W. Fan, H. B. Hu, J. W., Hu, M. H. Huang, D. Y. Li, M. J. Liu, Z. Z. Lv, T. Y. Lian, X. Pan, H. Sun, W. X. Wang, Y. L. Wang, X. P. Xu, Y. F. Xu, H. N. Yang, M. Zhang, W. D. Zhang, W. J. Zhang, Z. Zhang, D. H. Zhao (NAOC, CAS), Y. Chen, S. M. Jia, W. W. Cui, D. W. Han, C. K. Li, L. M. Song, X. F. Zhao, J. Zhang, S. N. Zhang (IHEP, CAS), E. Kuulkers, A. Santovincenzo (ESA), P. O'Brien (Univ. of Leicester), K. Nandra, A. Rau (MPE), B. Cordier (CEA) report on behalf of the Eintein Probe team:

We report on the detection of an X-ray transient detected by EP-WXT, which triggered the on-board processing unit at 2024-10-01 19:00:08.6 (UTC) (trigger ID: 01709064214). The source position is R.A. = 352.558 deg, DEC = -2.614 deg (J2000) with an uncertainty of about 2.8 arcmin (radius, 90% C.L. statistical and systematic). An autonomous observation on the X-ray transient was performed by EP-FXT, which also detected an X-ray source at R.A. = 352.54575 deg, DEC = -2.6234 deg (J2000) with an uncertainty of about 30 arcsec (radius, 90% C.L. statistical and systematic), consistent with the position of the WXT transient within the uncertainties. An M-type, high proper motion star 2MASS J23301129-0237227/2RXS J233013.0-023738, is at a distance of about 46 pc and located about 5.1 arcsec away from the position detected by FXT. We suggest that this X-ray transient is most likely a stellar flare event occurred on this star.

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).