TITLE:   GCN CIRCULAR
NUMBER:  33663
SUBJECT: GRB 230420A: BOOTES-5/JGT optical afterglow detection
DATE:    23/04/21 07:47:36 GMT
FROM:    Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>

Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado, I. Perez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy (IAA-CSIC), D. Hiriart and W. H. Lee (UNAM), C. J. Perez del Pulgar (UMA) and I. Carrasco (SMA) and I. H. Park (SKKU), on behalf of a larger collaboration, report:

Following the detection of GRB 230420A by Swift (Klingler et al. GCNC 33658), the BOOTES-5/JGT 0.6m robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) automatically observed the GRB location starting on Apr. 20, 10:21:03 UT (~ 122 s after trigger). A series of images in clear filter were gathered. A new optical transient was found within the enhanced Swift/XRT position (Osborne et al. GCNC 33661) for which we measure a magnitude of 17.7 on the initial 10 s exposure frame, which we propose to be the optical afterglow for GRB 230420A.

We thank the staff at Observatorio Astronomico Nacional in San Pedro Martir for their excellent support.