GCN Circular 38081
Subject
EP241104a: EP detection of GRB 241104A X-ray emission
Date
2024-11-05T13:00:44Z (2 months ago)
Edited On
2024-11-05T14:52:17Z (2 months ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
H. Zhou (PMO, CAS), R.-Z. Li (YNAO, CAS), Q. C. Liu (TSU), H. Q. Cheng, Z. X. Ling (NAO,CAS) report on behalf of the Einstein Probe team:
We report on the detection of an X-ray transient, designated EP241104a, by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission. The WXT position of EP241104a is R.A.= 32.574 deg, DEC = 31.555 deg (J2000) with an uncertainty of 2.7 arcmin (radius, 90% C.L. statistical and systematic).
The lightcurve of the transient observed by the WXT lasts around 400 seconds and has a peak flux of ~5.0 x 10^-10 erg/s/cm^2 in the 0.5-4 keV band. The average 0.5-4 keV spectrum can be fitted with an absorbed power law with a photon index of 1.3(-0.7, +0.8) and a fixed absorbing column density value of 7.8 x 10^20 cm^-2. The derived average unabsorbed 0.5-4 keV flux is 2.0(-1.1, +1.0) x 10^-10 erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters.
EP241104a is spatially and temporally consistent with GRB 241104A (Fermi GBM Team, GCN 38075; Vladimir et al., GCN 38076; Stéphane et al., GCN 38078). The EP-WXT detection is about 4 minutes after the Fermi-GBM trigger (2024-11-04T18:30:15). Before the detection, the WXT observation was interrupted by the Earth obscuration for about 1.5 ks which covered the Fermi GBM trigger time. 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).