{
  "subject": "GRB 250507A: KAIT optical upper limit",
  "eventId": "GRB 250507A",
  "createdOn": 1746729451483,
  "submitter": "Weikang Zheng at UC Berkeley <weikang@berkeley.edu>",
  "bibcode": "2025GCN.40400....1Z",
  "circularId": 40400,
  "body": "WeiKang Zheng (UCB), Xuhui Han (NAOC), Pinpin Zhang (NAOC) and\n\nAlexei V. Filippenko (UCB) report on behalf of the KAIT GRB team:\n\n\nThe 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at\n\nLick Observatory, observed the field of SVOM GRB 250507A (Wang\n\net al., GCN 40374) starting at 06:37:30, May 07 UT, 165 seconds\n\nafter the burst. Observations were performed in 3 x 3 tiling mode,\n\nand a set of clear (roughly R) filter images were obtained.\n\nPreliminary analysis do not reveal any new optical counterpart\n\ncandidate within the X-ray afterglow error circles (Maggi et al.,\n\nGCN 40381; Zhang et al., GCN 40385; Osborne et al., GCN 40389),\n\nneither in single image, nor in the co-add images. We estimate\n\nthe limiting magnitude of our coadd image to be ~20.0 mag at a\n\nmid-time of 15.0 minutes after the burst, consistent with the\n\nupper limit reported by other groups (Ducoin et al., GCN 40376;\n\nXin et al., GCN 40379; Brivio et al., GCN 40380)\n",
  "submittedHow": "email"
}