{
  "bibcode": "2021GCN.29760....1W",
  "body": "Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Simone Dichiara\n(GSFC/UMD), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), Oc��lotl Lopez\n(UNAM), Diego Gonzalez (UNAM), Margarita Pereyra (UNAM), Srihari Ravi (ASU), and\nEleonora Troja (GSFC/UMD) report:\n\nWe observed the field of the Fermi/GBM GRB 210404.141 (trigger 639199407) with\nthe DDOTI wide-field imager at the Observatorio Astron��mico Nacional on Sierra\nSan Pedro Martir (http://ddoti.astroscu.unam.mx) from 2021-04-04 04:37 UTC to\n2021-04-04 12:14 UTC (from 1.2 to 8.9 hours after the trigger).\n\nWe observed a region covering aproximately 21 degrees in RA and 20 degrees in\ndeclination (about 420 square degrees) centered on the Fermi GBM ground position\nof 12:26:43 -01:18:00 (J2000). We obtained between 2600 and 3400 seconds of\nexposure per pointing in the w filter. We calibrated our images against the\nAPASS catalog.\n\nWe do not detect any fading sources to our 10-sigma limit, which varies over the\nfield between 20.31 and 20.71.\n\nWe thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir.",
  "circularId": 29760,
  "createdOn": 1617559156000,
  "email": "alan@astro.unam.mx",
  "subject": "GRB 210404.141: DDOTI Upper Limits",
  "submitter": "Alan M Watson at UNAM  <alan@astro.unam.mx>",
  "eventId": "GRB 210404.141"
}