[vsnet-grb-info 20890] GRB 180720B: LCO optical afterglow observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22988
SUBJECT: GRB 180720B: LCO optical afterglow observations
DATE:    18/07/21 04:59:42 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani at dark-cosmology.dk>

Nicolas Crouzet (IAC) and Daniele B. Malesani (DAWN/NBI and DARK/NBI) 
report:

We observed the optical afterglow of GRB 180720B (Siegel et al., GCN 
22973; Martone et al., GCN 22976) using the 0.4-m telescope located at 
the Teide Observatory, part of the Las Cumbres Observatory (LCO) 
telescope network.

A single 600-s exposure in the SDSS r band was obtained with mean time 
July 21.094 UT (0.495 days after the GRB). The PSF of the image is not 
optimal, being double-peaked.

Aperture photometry, compared to nearby stars from the Pan-STARRS 
catalog, provides for the afterglow a preliminary magnitude r = 17.85 +- 
0.10 AB.