{
  "bibcode": "2021GCN.29935....1P",
  "body": "Margarita Pereyra (UNAM), Nat Butler (ASU), Alan M. Watson (UNAM),\nEleonora Troja (GSFC/UMD),  Simone Dichiara (GSFC/UMD), Rosa L. Becerra\n(UNAM), William H. Lee (UNAM), Oc��lotl L��pez,  Diego Gonzalez (UNAM),\nAlexander Kutyrev (GSFC/UMD), and Srihari Ravi (ASU), report:\n\nWe observed the field of the likely long Fermi GRB 210503A (trigger\n641763254, GCN #29927, Fermi GBM Team) with the DDOTI/OAN wide-field imager\nat the Observatorio Astron��mico Nacional on Sierra San Pedro M��rtir (\nhttp://ddoti.astroscu.unam.mx) on 2021-05-04 from 07:02 to 11:38 UTC (11.5\nto   16 hours after the event).\n\nWe observed a region of 20.4 degrees in RA by 20.4 degrees in declination,\nwith a 3 x 2 grid, centered on the Fermi GBM Final Position 328.93d\n+66.03d (J2000). This region contains 6 instrumental fields or about 400\nsquare degrees. We obtained 1560 seconds of exposure per instrumental field\nin the w filter. We obtained AB photometry by calibration against the APASS\ncatalog.\n\nWe detect no likely candidate for the afterglow to our 10-sigma upper\nlimits of\n\nw = 19.32 to 19.93 (interquartile range).\n\nWe thank the staff of the Observatorio Astron��mico Nacional in San Pedro\nM��rtir.\n\n--",
  "circularId": 29935,
  "createdOn": 1620168503000,
  "email": "mpereyra@astro.unam.mx",
  "subject": "Fermi GRB 210503A: DDOTI Upper Limits on the Afterglow",
  "submitter": "Emma Margarita Pereyra Talamantes at IA-UNAM Ensenada  <mpereyra@astro.unam.mx>",
  "eventId": "GRB 210503A"
}