EP240408a: EP-WXT detection of a fast X-ray transient
Abstract
We report on the detection of a fast X-ray transient EP240408a at %2024-04-08T17:56:30 (UTC) by the Wide-field X-ray Telescope (WXT) on %board the Einstein Probe (EP) mission during a calibration %observation. The position of the source is R.A. = 158.840 deg, DEC = %-35.749 deg (J2000) with an uncertainty of 3 arcmin (radius, 90% C.L. %statistical and systematic). The light curve of the source shows a %duration of approximately 10 seconds. The peak flux reaches ~1.4 x %10^-8 erg/s/cm^2 in the 0.5-4.0 keV band. The averaged spectrum can %be fitted by an absorbed power-law with NH fixed at the Galactic %value of 6.23 x 10^20 cm^-2 and a photon index of 1.1(-0.7/+0.8). The %derived average unabsorbed 0.5-4.0 keV flux is 4.0(-1.3/+1.3) x 10^-9 %erg/s/cm^2. No previously known bright X-ray sources have been found within the 3 arcmin region around the source position. The derived source parameters may be subject to larger uncertainties than those quoted here since in-orbit calibration of the instrument is still in progress. Further follow-up observations are strongly encouraged to identify the nature of this X-ray transient. The above observation was made with the WXT instrument during the commissioning phase of EP. 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). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES.
- Publication:
-
GRB Coordinates Network
- Pub Date:
- April 2024
- Bibcode:
- 2024GCN.36053....1H