{
  "bibcode": "2019GCN.26015....1W",
  "body": "Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H.\nLee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska\n(UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen\nLittlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jes��s Gonz��lez (UNAM), Carlos\nRom��n-Z����iga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou\n(U. Wash.), and Vicki Toy (UMD) report:\n\nWe observed the field of GRB 191016A (Gropp et al., GCN Circ. 26008) with the\nReionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m\nHarold Johnson Telescope at the Observatorio Astron��mico Nacional on Sierra San\nPedro M��rtir from 2019/10 16.18 to 2019/10 16.26 UTC (0.12 to 2.13 hours after\nthe BAT trigger), obtaining a total of 0.99 hours exposure in the r and i bands\nand 0.54 hours exposure in the Z, Y, J, and H bands.\n\nWe detect a source coincident with the COATLI afterglow candidate (Watson et\nal., GCN Circ. 26010). In comparison with the SDSS DR9 and 2MASS catalogs, we\nobtain the following detections:\n\n  r\t= 16.42 +/- 0.00\n  i\t= 16.16 +/- 0.00\n  Z\t= 15.91 +/- 0.01\n  Y\t= 15.78 +/- 0.01\n  J\t= 15.42 +/- 0.01\n  H\t= 15.10 +/- 0.01\n\nThese magnitudes are in the AB system and are not corrected for Galactic\nextinction in the direction of the GRB.\n\nThe light curve shows similar behaviour to that reported by Watson et al. We see\nthe source rise from r = 16.8 to r = 15.3 before falling to r = 17 at the end of\nthese observations.\n\nIn subsequent observations we added images in the g filter and determined that\nthe g - r color is 0.44 +/- 0.01. This strongly suggests that the GRB is at z <\n4 (Littlejohns et al. 2014).\n\nWe thank the staff of the Observatorio Astron��mico Nacional in San Pedro M��rtir.",
  "circularId": 26015,
  "createdOn": 1571275875000,
  "email": "alan@astro.unam.mx",
  "subject": "GRB 191016A: RATIR Optical and NIR Observations",
  "submitter": "Alan M Watson at UNAM  <alan@astro.unam.mx>",
  "eventId": "GRB 191016A"
}