GCN Circular 37997
Subject
EP241030a: EP detection of GRB 241030A X-ray Afterglow
Date
2024-10-31T06:28:02Z (3 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
H. Z. Wu (HUST), B. T. Wang (YNAO, CAS), D. F. Hu, Y. F. Liang (PMO,CAS), Q. Y. Wu, S. Q. Jiang, H. N. Yang, C. C. Jin, Z. X. Ling (NAO,CAS) report on behalf of the Einstein Probe team:
We report on the detection of an X-ray transient, designated EP241030a, by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission. The observation started at 2024-10-30T06:33:18(UTC) with an exposure of about 1.2 ks. The WXT position of EP241030a is R.A.= 343.013 deg, DEC = 80.449 deg (J2000) with an uncertainty of 2.4 arcmin (radius, 90% C.L. statistical and systematic).
The average 0.5-4 keV spectrum can be fitted with an absorbed power-law with a photon index of 2.5(+0.8/-0.7) (with a column density fixed at the Galactic value of 1.8 x 10^21 cm^-2). The derived average unabsorbed 0.5-4 keV flux is 7.5(+3.0/-2.4) x 10^-11 erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters.
EP241030a is spatially and temporally consistent with GRB 241030A (Fermi GBM Team, GCN 37955; Klingler et al., GCN 37956; Wang et al., GCN 37972; Ridnaia et al., GCN 37982). We thus consider the EP-WXT detection the X-ray afterglow of GRB 241030A. EP-FXT follow-up observation has been arranged.
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).