{
  "bibcode": "2018GCN.22806....1W",
  "body": "Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), William\nH. Lee (UNAM), Carlos Rom��n-Z����iga (UNAM), Alexander Kutyrev (GSFC), and\nEleonora Troja (GSFC) report:\n\nWe observed the field of GRB 180620A (Evans et al., GCN 22798) with the\nCOATLI 50-cm telescope and interim imager at the Observatorio\nAstron��mico Nacional on the Sierra de San Pedro M��rtir\n(http://coatli.astroscu.unam.mx) from 2018-06-20 08:35:37 to 11:17:31\n(from 39.2 seconds after the trigger or 21.1 seconds after the alert to\n2.7 hours after the trigger), obtaining a total of 6250 seconds of\nexposure in the w filter.\n\nWe detect the source reported by Butler et al. (GCN Circ. 22799) with\n\nw = 18.00 +/- 0.02\n\nThis magnitude is in the USNO system and is not corrected for Galactic\nextinction in the direction of the GRB.\n\nOur light curve shows a sharp initial fall from 16.5 mag to 17.3 mag,\nfollowed by a slower rise to 16.7 mag (also seen by Butler et al.),\nfollowed by a monotonic fall to 19.0 mag.\n\nWe thank the COATLI technical team (Fernando ��ngeles, Oscar Chapa,\nSalvador Cuevas, Alejandro Farah, Jorge Fuentes, Rosal��a Langarica,\nFernando Quir��s, and Carlos Tejada) and the staff of the Observatorio\nAstron��mico Nacional.",
  "circularId": 22806,
  "createdOn": 1529507815000,
  "email": "alan@astro.unam.mx",
  "subject": "GRB 180620A: COATLI Detection and Light Curve",
  "submitter": "Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>",
  "eventId": "GRB 180620A"
}