TITLE:   GCN CIRCULAR
NUMBER:  30080
SUBJECT: GRB 210306A: LBT observations of the likely host galaxy
DATE:    21/05/26 12:33:42 GMT
FROM:    Andrea Rossi at INAF  <andrea.rossi@inaf.it>

A Rossi (INAF-OAS) and D. B. Malesani (DTU space) report on behalf of 
the CIBO collaboration:

We observed the field of GRB 210306A (D'Elia et al., GCN 29597) 
simultaneously in the r' and z' bands with the LBC imager mounted on LBT 
(Mt Graham, AZ, USA). We obtained 20min of imaging on 2021-05-10, 65 
days after the burst trigger and 60 days after our first observation 
(Rossi et al., GCN 29645). Observations were performed under good 
weather conditions with an average seeing of ~1.3".

At the location of the optical afterglow, we detected an object which is 
likely the GRB host galaxy. We measure the following AB magnitudes:

r=24.6+-0.2
z=24.4+-0.4

calibrated against SDSS field stars.

We acknowledge the excellent support from the LBTO and LBT-INAF staff, 
particularly A. Cardwell, S. Allanson, F. Cusano, S. Paiano and D. 
Paris, in obtaining these observations.