{
  "bibcode": "2018GCN.22910....1W",
  "body": "Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Carlos\nRom��n-Z����iga (UNAM), and William H. Lee (UNAM) report:\n\nWe observed the field of the GRB 180706A (Stamatikos et al., GCN Circ.\n22909) with the COATLI 50-cm telescope and interim imager (Watson et al.\n2016, Proc. SPIE, 9908, 50) at the Observatorio Astron��mico Nacional on\nthe Sierra de San Pedro M��rtir from 2018-07-06 08:25:26.83 (29.5 seconds\nafter alert and 46.4 seconds after trigger) to 08:50:34, obtaining 795\nseconds of exposure in the w filter.\n\nWe detect an uncatalogued source in the XRT error region with a\npreliminary magnitude of\n\n  w = 18.73 +/- 0.08\n\nThis magnitude is calibrated against the USNO-B1 catalog (adjusted to an\napproximate AB system) and is not corrected for Galactic extinction in\nthe direction of the GRB.\n\nAt the moment we have no information on fading. Further observations are\nplanned.\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": 22910,
  "createdOn": 1530867777000,
  "email": "alan@astro.unam.mx",
  "subject": "GRB 180706A: COATLI Optical Detection",
  "submitter": "Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>",
  "eventId": "GRB 180706A"
}