TITLE:   GCN CIRCULAR
NUMBER:  31775
SUBJECT: GRB220319A: Optical observations from NOT
DATE:    22/03/20 13:47:37 GMT
FROM:    Antonio de Ugarte Postigo at OCA  <deugarte@oca.eu>

A. de Ugarte Postigo (OCA) and R. Clavero Jimenez (NOT) 
report on behalf of a larger collaboration:

We observed the field of GRB220319A (Page et al. GCN31769) 
with the 2.5m Nordic Optical Telescope equipped with AlFOSC. 
Observations consisted of 3x300s in r and 5x200s in z. Due to variable 
weather conditions, the observation was attempted twice, between 
22:12 and 22:47 UT and between 00:10-00:48 UT (starting 4.53 and 
6.49 hr after the burst). We also note the high background due to the 
illumination from the almost full Moon. The first attempt had a seeing 
of 1.5��� in r and 1.3��� in z and was affected by some dome vignetting 
due to the low elevation. The second observation had better conditions 
with 1.2��� seeing in r and 1.1��� in z. 

In a preliminary reduction, we do not detect any new source within or 
near the refined XRT position (Goad et al. GCN 31771) in any of the 
images. We estimate a 3-sigma limit of z > 21.5 mag in the first epoch 
and > 22.5 mag in the second epoch.