TITLE:   GCN CIRCULAR
NUMBER:  38517
SUBJECT: GRB 241209A: EP-FXT follow-up observations
DATE:    24/12/10 08:36:26 GMT
FROM:    Yu-Han Yang at University of Rome Tor Vergata <yyang@roma2.infn.it>

E. Troja (U Rome), Y. L. Wang (NAO, CAS), Y. Wang (PMO, CAS), H. L. Peng (NNU), W. D. Zhang (NAO,CAS), Y. -H. Yang (U Rome), R. L. Becerra (U Rome) report on behalf of the Einstein Probe team:

We performed a follow-up observation of the short GRB 241209A detected by Fermi/GBM (GCN 38474) and Swift/BAT (GCN 38476) with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission. The observation began at 2024-12-09T18:20:45 (UTC), about ~ 12.75 hours after the trigger, for a total exposure time of 4093 seconds.

At the position of the XRT counterpart (GCN 38486), we detect no new source. Assuming a photon index of 1.5 and a Galactic absorption of NH = 2E20 cm^-2, we derive an upper limit of ~3E-14 erg/cm2/s (0.5-10 keV; 90% confidence level). 

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.