{
  "body": "Katherine Mora, Eyouel Abate, Ansel Parke, WeiKang Zheng\n\nand Alex Filippenko (UC Berkeley) report on behalf of the\n\nKAIT GRB team:\n\n\nWe observed the field of EP250421a (Zhao et al., GCN 40198)\n\nwith the 1-m Nickel telescope located at Lick observatory,\n\nCalifornia. Observations were performed in the R band with\n\n600s x 6 exposures. In our coadd image, we do not detect the\n\noptical afterglow (Lee et al., GCN. 40192; Fu et al., GCN\n\n40193; Liu et al., GCN 40197), with an upper limit of R >\n\n20.5 (Vega) at a mid-time of 14.9 hours after the trigger.\n",
  "circularId": 40220,
  "submittedHow": "email",
  "createdOn": 1745450016545,
  "bibcode": "2025GCN.40220....1M",
  "subject": "EP250421a: Nickel optical upper limit",
  "eventId": "EP250421a",
  "submitter": "Weikang Zheng at UC Berkeley <weikang@berkeley.edu>"
}