[vsnet-grb-info 27895] GRB 210511B: DDOTI Upper Limits on the Afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29998
SUBJECT: GRB 210511B: DDOTI Upper Limits on the Afterglow
DATE:    21/05/12 00:14:52 GMT
FROM:    Kin O. C. L. Mendoza at Instituto de Astronoma, UNAM  <koclopez at astro.unam.mx>

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

We observed the field of the Fermi - GBM event GRB 210511B (Fermi
Collaboration, GCN Circ. 29988) with the DDOTI wide-field imager at the
Observatorio Astronómico Nacional on Sierra San Pedro Martir (
http://ddoti.astroscu.unam.mx) from 2021-05-11 11:49:26 to 12:01:38 UTC
(0.38 to 0.58 hours after the trigger) and obtained 6 minutes of exposure
in the w filter. The images were obtained after the astronomical twilight.

We observed a region covering approximately 14 degrees in RA and 10 degrees
in declination, with a 2 x 1 grid, including the entire initial uncertainty
region distributed in the GCN Notice (Fermi Collaboration, GCN Circ. 29988)

Comparing to the Pan-STARRS DR1 catalog, we detect no uncatalogued point
sources to a 10-sigma limiting magnitude of w = 18.39.

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