{
  "bibcode": "2021GCN.30078....1P",
  "body": "Margarita Pereyra (UNAM), Nat Butler (ASU), Alan M. Watson (UNAM), Eleonora\nTroja (GSFC/UMD),  Simone Dichiara (GSFC/UMD), Rosa L. Becerra (UNAM),\nWilliam H. Lee (UNAM), Oc��lotl L��pez,  Diego Gonzalez (UNAM), Alexander\nKutyrev (GSFC/UMD), and Srihari Ravi (ASU), report:\n\nWe observed the field of the likely long Fermi GRB 210524B  (trigger\n643548039, GCN #30074, 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 2021-05-25 from 03:32:24 to 04:48:24 UTC\n(16.19 to 17.46 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 RA: 148.460\nDEC: 7.79 (J2000 degrees). This region contains 6 instrumental fields or\nabout 400 square degrees. We obtained 600 to 720 seconds of exposure per\ninstrumental field in the w filter. We obtained AB photometry by\ncalibration against the APASS catalog.\n\nWe detect no likely candidate for the afterglow to our 10-sigma upper\nlimits of w = 18.52 - 18.84 (inter-quartile).\n\nWe thank the staff of the Observatorio Astron��mico Nacional in San Pedro\nM��rtir.",
  "circularId": 30078,
  "createdOn": 1621959945000,
  "email": "mpereyra@astro.unam.mx",
  "subject": "Fermi GRB 210524B: DDOTI Upper Limits on the Afterglow",
  "submitter": "Emma Margarita Pereyra Talamantes at IA-UNAM Ensenada  <mpereyra@astro.unam.mx>",
  "eventId": "GRB 210524B"
}