TITLE:   GCN CIRCULAR
NUMBER:  28987
SUBJECT: GRB 201203A: DDOTI Observations 
DATE:    20/12/03 08:54:12 GMT
FROM:    Alan M Watson at UNAM  <alan@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 Swift/BAT GRB 201203A (Dichiara et al., GCN Circ.
28985) with the DDOTI wide-field imager at the Observatorio Astronómico Nacional
on Sierra San Pedro Martir (http://ddoti.astroscu.unam.mx) from 2020-12-03
06:57 UTC to 08:31 UTC (from 5.5 to 99 minutes after the trigger).

We observed a region covering aproximately 7 degrees in RA and 10 degrees in
declination (about 70 square degrees), including the entire BAT uncertainty
region centered on 02:32:19.18 -26:32:15.0 (J2000). We obtained 4290 seconds of
exposure in the w filter at high airmass and with almost full Moon. We
calibrated our images against the APASS DR10 catalog. Our 5-sigma limiting
magnitudes is 19.9.

Compared to the USNO-B1, Pan-STARRS DR1, and APASS DR10 catalogs, we detect no
uncataloged sources to our 5-sigma limit in the BAT 90% uncertainty region. No
XRT detection is available at this moment.

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