TITLE:   GCN CIRCULAR
NUMBER:  43745
SUBJECT: EP260214b: NOT optical counterpart detection
DATE:    26/02/15 05:27:38 GMT
FROM:    L. B. He at NAOC <helb@bao.ac.cn>

L.B. He, Z.P. Zhu, J. An, X. Liu, S.Q. Jiang, D. Xu (NAOC), S.Y. Fu (HUST), J.P.U. Fynbo (DAWN/NBI), K. Valeckas (NOT) report on behalf of a large collaboration:

We observed the field of EP260214b detected by EP/WXT (Yang et al., GCN 43744) using the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. 

In a single of 220 s Sloan r-band exposure we detect a brightened source within the EP/FXT error circle (Yang et al., GCN 43744) at coordinates:

R.A.(J2000) = 12:45:01.96 = 191.2582
Dec.(J2000) = 23:51:13.10 = 23.8536

with an uncertainty of ~0.5 arcsec. We measure r' = 20.90 +/- 0.04 at ~2.22 hrs post-trigger, calibrated with Pan-STARRS1-dr2 catalog and not corrected for Galactic extinction. The source is brighter than its underlying host galaxy by ~2.0 mag, and the galaxy has a photometric redshift  z ~ 1.04 from Legacy Survey dr9.

We suggest the source is the optical counterpart of EP260214b.