{
  "submitter": "Zipei Zhu at NAOC <zpzhu@nao.cas.cn>",
  "bibcode": "2024GCN.38703....1Z",
  "subject": "GRB 241228A: NOT optical upper limits",
  "circularId": 38703,
  "body": "Z.P. Zhu (NAOC), J. T. Palmerio (CEA/Irfu), J. An, D. Xu (NAOC), D. B. Malesani (DAWN/NBI and Radboud Univ.), T. Pursimo (NOT) report on behalf of a large collaboration:\n\nWe observed the field of GRB 241228A detected by Swift (D'Elia et al., GCN 38681), using the ALFOSC instruments mounted on the Nordic Optical Telescope (NOT), with 3 x 300 s in the SDSS-r band and 5 x 200 s photometry in the SDSS-z band. Observations started at 21:10:46 UT on 2024-12-28, i.e. 0.72 day after the trigger.\n\nNo new source is detected within the Swift/XRT enhanced error circle (Evans et al., GCN 38683), being consistent with the previous reports (Kuin et al., GCN 38685; Mohan et al., GCN 38689; Lipunov et al., GCN 38693), down to the 5-sigma upper limits of r > 22.0 (AB) and z > 20.5 (AB), calibrated with nearby Pan-STARRS stars without Galactic extinction correction.\n\n\n",
  "eventId": "GRB 241228A",
  "submittedHow": "email-legacy",
  "createdOn": 1735466647792
}