TITLE:   GCN CIRCULAR
NUMBER:  27156
SUBJECT: GRB 200219C: DDOTI Observations 
DATE:    20/02/20 18:58:16 GMT
FROM:    Alan M Watson at UNAM  <alan@astro.unam.mx>

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

We observed the field of 200219C, detected by both Fermi/GBM (Fermi GBM
Team, GCN Circ. 27145) and Fermi/LAT (Dirirsa et al., GCN Circ. 27151),
with the DDOTI/OAN wide-field imager at the Observatorio Astronomico
Nacional on Sierra San Pedro Martir (http://ddoti.astroscu.unam.mx) on
the night of 2020-02-20 UTC.

We observed from 2020-02-20 11:37 UTC to 2020-02-13 13:08 UTC (from 11.7
to 13.2 hours after the event) obtaining 72 minutes of exposure in the w
filter. We calibrate our images against the APASS catalog. Our 5-sigma
limiting magnitude is w = 20.4.

Comparing our observations to the USNO-B1 and PanSTARRS PS1 DR2
catalogs, we detect no uncatalogued sources in the Fermi/LAT error
region (Dirirsa et al., GCN Circ. 27151) to our 5-sigma limit.

The Fermi/LAT error includes the probably XRT afterglow candidate (Evans
et al., GCN Circ. 27152) at 17:30:02.34 +10:32:22.9 J2000 (source #2
at https://www.swift.ac.uk/xrt_products/TILED_GRB00088/). We see no
evidence for an optical counterpart at this position to our 5-sigma
limit.

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