{
  "submitter": "Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197@gmail.com>",
  "body": "Viraj Karambelkar (Caltech), Kaew Tinyanont (NARIT), Sam Rose (Caltech),\nTomas Ahumada (Caltech), Robert Stein (Caltech), Nathan Lourie (MIT),\nDanielle Frostig (MIT), Geoffrey Mo (MIT), Robert Simcoe (MIT), Mansi\nKasliwal (Caltech)\n\nWe observed the field of the long GRB 240418A (GCN 36162; GCN 36166; GCN\n36177; GCN 36184) in the near-infrared K-prime band with the NIRES\nacquisition camera on the Keck II telescope starting at UTC\n2024-04-19T09:56:00 (~14 hours since trigger). The observations lasted for\n300 sec. (25 sec, 12 coadds).\n\nWe find an uncataloged source at RA = 239.3744, Dec = 23.5961 that is 3.1\narcsec from the centroid of the GRB position and within its 3.6 arcsec\nlocalization (from GCN 36166). This source has m_Kp ~ 20.9 +/- 0.1 mag\n(AB). There is no source at this location in an archival Ks-band image from\nthe UKIRT hemisphere survey (Lucas et al. 2008), and a deep optical image\nfrom the Legacy Survey. However, we note that our NIRES observations are\nmore sensitive than the archival UKIRT observations, so it is possible that\nthe NIRES source is an unrelated background source.\n\nWe also observed this source in the J-band with the WINTER camera on the\nPalomar 40-inch telescope (Lourie et al. 2021) on 2024-04-19T09:00:14 and\ndid not detect it to a limiting magnitude of m_J ~ 19 mag.\n\nFurther observations are encouraged.\n",
  "circularId": 36199,
  "subject": "GRB240418A - Candidate afterglow from NIRES",
  "submittedHow": "email-legacy",
  "createdOn": 1713641735212,
  "eventId": "GRB 240418A",
  "bibcode": "2024GCN.36199....1K"
}