[vsnet-grb-info 27976] ZTF21aayokph (AT2021lfa): LBT optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30079
SUBJECT: ZTF21aayokph (AT2021lfa): LBT optical observations
DATE:    21/05/26 08:07:05 GMT
FROM:    Andrea Rossi at INAF  <andrea.rossi at inaf.it>

A. Rossi, E. Palazzi, F. Cusano (INAF-OAS) report on behalf of the 
GRAWITA collaboration:

We observed the field of ZTF21aayokph/AT2021lfa (Yao et al., GCN 29938) 
simultaneously in the r' and z' bands with the LBC imager mounted on LBT 
(Mt Graham, AZ, USA). We obtained 20min of imaging on 2021-05-11 and 
starting at 6:26 UT, 6 days after the first communication by ZTF. 
Observations were performed under good weather conditions with an 
average seeing of ~1.1".

We clearly detect the host galaxy at the position of the afterglow and 
we preliminary measure the following AB magnitudes
r=23.9+-0.1
z=24.1+-0.2
calibrated against SDSS field stars.

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