{
  "bibcode": "2019GCN.24690....1W",
  "body": "Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Diego\nGonz��lez (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM),\nMargarita Pereyra (UNAM), and Eleonora Troja (GSFC) report:\n\nWe observed the field of Fermi GBM/LAT GRB 190530A (Fermi GBM Team, GCN\nCirc. 24676; Longo et al., GCN Circ. 24679) with the COATLI 50-cm\ntelescope and interim imager at the Observatorio Astron��mico Nacional on\nthe Sierra de San Pedro M��rtir (http://coatli.astroscu.unam.mx) from\n2019-05-31 03:33 to 06:27 (from 17.2 to 20.1 hours after the trigger),\nobtaining a total of 8190 seconds of exposure in the w filter.\n\nWe detect the afterglow (Lipunov et al., GCN Circ. 24680; Melandri et\nal., GCN Circ. 24689) at\n\n  w = 18.18 +/- 0.01\n\nDuring our observations, the afterglow fades with a power-law index of\n-1.05 +/ 0.25.\n\nOur w magnitudes are calibrated against the Pan-STARRS1 catalog, are on\nan approximate AB system, and are not corrected for Galactic extinction\nin the direction of the GRB.\n\nWe thank the COATLI technical team and the staff of the Observatorio\nAstron��mico Nacional.",
  "circularId": 24690,
  "createdOn": 1559284882000,
  "email": "alan@astro.unam.mx",
  "subject": "GRB 190530A: COATLI Optical Detection of the Fading Afterglow",
  "submitter": "Alan M Watson at UNAM  <alan@astro.unam.mx>",
  "eventId": "GRB 190530A"
}