TITLE: GCN CIRCULAR NUMBER: 40220 SUBJECT: EP250421a: Nickel optical upper limit DATE: 25/04/23 23:13:36 GMT FROM: Weikang Zheng at UC Berkeley <weikang@berkeley.edu> Katherine Mora, Eyouel Abate, Ansel Parke, WeiKang Zheng and Alex Filippenko (UC Berkeley) report on behalf of the KAIT GRB team: We observed the field of EP250421a (Zhao et al., GCN 40198) with the 1-m Nickel telescope located at Lick observatory, California. Observations were performed in the R band with 600s x 6 exposures. In our coadd image, we do not detect the optical afterglow (Lee et al., GCN. 40192; Fu et al., GCN 40193; Liu et al., GCN 40197), with an upper limit of R > 20.5 (Vega) at a mid-time of 14.9 hours after the trigger. View this GCN Circular online at https://gcn.nasa.gov/circulars/40220. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...