{
  "bibcode": "2019GCN.26010....1W",
  "body": "Alan M. Watson (UNAM),  Nat Butler (ASU), Rosa L. Becerra (UNAM), Diego Gonz��lez\n(UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Margarita Pereyra\n(UNAM), and Eleonora Troja (GSFC) report:\n\nAlan M. Watson (UNAM),  Nat Butler (ASU), Rosa L. Becerra (UNAM), Diego Gonz��lez\n(UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Margarita Pereyra\n(UNAM), and Eleonora Troja (GSFC) report:\n\nWe observed the field of GRB 191016A (Gropp et al., GCN Circ. Gropp) with the\nCOATLI 50-cm telescope and interim imager at the Observatorio Astron��mico\nNacional on the Sierra de San Pedro M��rtir (http://coatli.astroscu.unam.mx) from\n2019-10-16 04:40:19 (378.7 seconds after the trigger and 21.8 seconds after the\nalert) to 04:49, obtaining a total of 1200 seconds of exposure in the w filter.\n\nWe detect a bright uncataloged source at 02:01:04.75 +24:30:36.8 J2000 (+/- 0.5\narcsec), about 91 arcsec from the BAT position. The source rises from w = 16.5\nto w = 15.0 before fading. We suggest this is the afterglow.\n\nOur w magnitudes are calibrated against the Pan-STARRS1 catalog, are on an\napproximate AB system (Becerra et al., 2019, ApJ, 872, 118), and are not\ncorrected for Galactic extinction in the direction of the GRB.\n\nObservations are continuing.\n\nWe thank the COATLI technical team and the staff of the Observatorio Astron��mico\nNacional.",
  "circularId": 26010,
  "createdOn": 1571202218000,
  "email": "alan@astro.unam.mx",
  "subject": "GRB 191016A: COATLI Optical Observations and Detection of the Afterglow",
  "submitter": "Alan M Watson at UNAM  <alan@astro.unam.mx>",
  "eventId": "GRB 191016A"
}