GCN Circular 37864
Subject
EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
Date
2024-10-25T04:34:13Z (2 months ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
D. Y. Li (NAO, CAS), Z. Y. Liu, M. Q. Huang (USTC), J. Q. Peng (IHEP, CAS), C. C. Jin (NAO, CAS) report on behalf of the Eintein Probe team:
We report on the detection of an X-ray transient detected by EP-WXT, EP241025a, which triggered the on-board processing unit at 2024-10-25T01:36:45 (UTC) (trigger ID: 01709111485). The trigger flux is estimated to be around 2e-10 erg/s/cm2 in 0.5-4 keV, assuming a spectral shape of absorbed power-law with a photon index of 2. An autonomous observation on the X-ray transient was performed by the EP-FXT about 3 minutes later, which also detected an X-ray source at R.A. = 333.6408 deg, DEC = 83.5772 deg (J2000) with an uncertainty of about 10 arcsecs (radius, 90% C.L. statistical and systematic), consistent with the position of the WXT transient within the uncertainties. The source flux is estimated to be around 5e-11 erg/s/cm2. We note that the trigger time and position of this X-ray transient are consistent with that of GRB 241025A (Swift GCN 37859, Fermi GBM GCN 37860, SVOM/GRM GCN 37863).
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).