GCN Circular 45300
Subject
EP260806a: LCO likely optical counterpart
Event
Date
2026-08-07T02:28:30Z (16 days ago)
From
L. B. He at NAOC <helb@bao.ac.cn>
Via
Web form
L.B. He, J. An, S.Q. Jiang, X. Liu, Z.P. Zhu, Z. Fan, W.X. Li, D. Xu(NAOC), S.Y. Fu (HUST), Y.L. Hua (PMO) report:
We observed the field of EP260806a detected by EP (Li et al., GCN 45299), using an LCO 1m telescope located at the Teide Observatory (Spain) equipped with the SINISTRO instrument. We obtained 6x200 s exposures in the SDSS-r filter at the mid time on 2026-08-07 at 01:06:30.678 UT (2.04 hr after the trigger).
After subtracting the archival Pan-STARRS image, we found a point source lie in a brightened known galaxy, which has a redshift of ~0.136 in REGALADE (Hugo et al. 2026), within the EP/FXT error circle. The coordinates of the optical counterpart are as follows:
R.A. (J2000) = 00:49:13.554 (12.30647 deg)
Dec. (J2000) = +35:33:39.72 (35.56103 deg)
with an uncertainty of ~ 0.5 arcsec. The source had r = 19.32 +/- 0.03 mag (background subtracted), calibrated with Pan-STARRS DR2 and not corrected for Galactic extinction.
We thus think the source is likely the optical counterpart.