GCN Circular 36701

S.-Y. Wu, I. Perez-Garcia, E. Fernandez-Garcia, M. D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy and A. J. Castro-Tirado (IAA-CSIC, Granada), P. J. Meintjes and H. J. van Heerden (UFS, South Africa), A. Martin-Carrillo and L. Hanlon (UCD, Ireland), M. Gritsevich (Univ. of Helsinki), D. R. Xiong (Yunnan Observatories of CAS) and C. J. Perez del Pulgar (UMA, Malaga), on behalf of a larger collaboration, report:

Following the detection of the fast X-ray transient EP240618a by the Einstein Probe (Sun et al. GCNC 36690), the BOOTES-6/DPRT 0.6m robotic telescope at Boyden Observatory in Maselspoort (South Africa) observed the fast X-ray transient location starting on June 18, 20:52 UT (~ 15.1 h after trigger) in different optical bands. No new optical source is detected on the co-added images (clear-filter) within the EP/FXT 30” radius error box down to 20.2 mag.

We thank the staff at Boyden Observatory for their excellent support.