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GCN Circular 29993

Fermi GRB 210510A: DDOTI Upper Limits on the Afterglow
2021-05-11T19:55:18Z (3 years ago)
Emma Margarita Pereyra Talamantes at IA-UNAM Ensenada <>
Margarita Pereyra (UNAM), Nat Butler (ASU), Alan M. Watson (UNAM),
Eleonora Troja (GSFC/UMD),  Simone Dichiara (GSFC/UMD), Rosa L. Becerra
(UNAM), William H. Lee (UNAM), Oc��lotl L��pez,  Diego Gonzalez (UNAM),
Alexander Kutyrev (GSFC/UMD), and Srihari Ravi (ASU), report:

We observed the field of the likely short Fermi GRB 210510A (trigger
642367205, GCN #29981, Fermi GBM Team) with the DDOTI/OAN wide-field imager
at the Observatorio Astron��mico Nacional on Sierra San Pedro M��rtir ( on 2021-05-11 from 03:24 to 10:45 UTC (8.1
to  15.4 hours after the event).

We observed a region of 20.4 degrees in RA by 20.4 degrees in declination,
with a 3 x 2 grid, centered on the Fermi GBM Final Position RA = 192.330,
Dec = +44.860 (J2000 degrees). This region contains 6 instrumental fields
or about 400 square degrees. We obtained 2280 to 2400 seconds of exposure
per instrumental field in the w filter. We obtained AB photometry by
calibration against the APASS catalog.

We detect no likely candidate for the afterglow to our 10-sigma upper
limits of w = 20.20 to 20.42 (interquartile range).

We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
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