TITLE:   GCN CIRCULAR
NUMBER:  36820
SUBJECT: EP240703a/GRB 240703A: TRT optical candidate likely not real
DATE:    24/07/04 10:42:33 GMT
FROM:    Dong Xu at NAOC/CAS <dxu@nao.cas.cn>

J. An (NAOC), S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), S.Q. Jiang, X. Liu, S.Y. Fu, Z.P. Zhu, D. Xu, Z. Fan, W.X. Li, N.C. Sun, Y.N. Wang (NAOC) report on behalf of a large collaboration:

Regarding our previously reported afterglow candidate of EP240703a/GRB 240703A (An et al., GCN 36815), we have checked the five 360 s R-band TRT images one by one.

First, the candidate is only present in one of the five images, and not in the other four images. Second, it looks sharper than its neighboring sources, although it does cover multiple pixels in the image. We thus re-did cosmic ray removal with a revised script, and this time the candidate basically disappeared while its neighboring sources were almost unaffected by the same cosmic ray removal process.

We thus conclude that the candidate is very likely not real.