[vsnet-grb-info 27903] GRB 210512.786: DDOTI Upper Limits on the Afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30006
SUBJECT: GRB 210512.786: DDOTI Upper Limits on the Afterglow 
DATE:    21/05/13 16:05:14 GMT
FROM:    Alan M Watson at UNAM  <alan at astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Simone Dichiara
(GSFC/UMD), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), Océlotl Lopez
(UNAM), Diego Gonzalez (UNAM), Margarita Pereyra (UNAM), Srihari Ravi (ASU), and
Eleonora Troja (GSFC/UMD) report:

We observed the field of the Fermi/GBM GRB 210512.786 (trigger 642538568) with
the DDOTI wide-field imager at the Observatorio Astronómico Nacional on Sierra
San Pedro Martir (http://ddoti.astroscu.unam.mx) from 2021-05-13 04:27 to 06:59
UTC (from 9.5 to 12.1 hours after the trigger).

We observed a region covering aproximately 20 degrees in RA and 20 degrees in
declination (6 instrumental fields or about 400 square degrees) centered on the
final GBM position of 09:11:43.20 +14:09:36.0 J2000 and obtained 1680 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 = 19.65 to 20.00 (interquartile range).

We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir.