GCN 45646: EP260917a: refined analysis of the EP-FXT observations

2026-09-19T15:44:15.672Z | rev 0 | event: EP260917a

T. Wu (AHNU), Q. J. Huang (PMO, CAS), K. R. Ni (CCNU), H. W. Pan (NAO, CAS) on behalf of the Einstein Probe (EP) team:
 
We performed a follow-up observation of EP260917a (Huang et al., GCN 45621). The observation started at 2026-09-18T10:38:31 (UTC, T0+25 hours). The effective exposure time of the observation is around 6 ks. On-ground analysis of the FXT data found a weak uncatalogued source at R.A. = 335.1539, DEC = 9.4534 (J2000) with an uncertainty of 10 arcsec (radius, 90% C.L. statistical and systematic), which is consistent with the WXT position (Huang et al., GCN 45621). The average unabsorbed flux is around 5e-14 erg/s/cm^2 in the 0.5-10 keV energy band.

No counterparts were detected by COLIBRÍ (Guelfand et al., GCN 45624), WINTER (Mohan et al., GCN 45628), or SVOM/VT (Li et al., GCN 45642). 

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).