[vsnet-grb-info 27854] HAWC GRB 210507.443: DDOTI Upper Limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29957
SUBJECT: HAWC GRB 210507.443: DDOTI Upper Limit 
DATE:    21/05/07 13:29:22 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 HAWC GRB 210507.443 (run 1010067 event 1345) with the
DDOTI wide-field imager at the Observatorio Astronómico Nacional on Sierra San
Pedro Martir (http://ddoti.astroscu.unam.mx) from 2021-05-10 10:44 to 11:36 UTC
(7 to 59 minutes after the trigger) and obtained 2520 seconds of exposure in the
w filter.

We observed a region covering aproximately 7 degrees in RA and 10 degrees in
declination (about 70 square degrees) including the entire HAWC uncertainty
region of 34.1 arcmin radius (90% containment, accounting for statistical
uncertainty only and assuming a Gaussian uncertainty). We calibrated our images
against the APASS catalog.

We do not detect any credible uncataloged sources to our 10-sigma limiting AB
magnitude of w = 20.55.

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