[vsnet-grb-info 28171] GRB 210619B: Liverpool Telescope r -band observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30274
SUBJECT: GRB 210619B: Liverpool Telescope r'-band observations
DATE:    21/06/20 15:37:41 GMT
FROM:    Martin Blazek at HETH/IAA-CSIC  <alf at iaa.es>

M. Blazek, D. A. Kann (both HETH/IAA-CSIC), A. de Ugarte-Postigo (HETH/IAA-CSIC,
DARK/NBI), C. Thoene and J.F. Agui Fernandez (both HETH/IAA-CSIC) report:

We observed the afterglow of GRB 210619B (Swift detection: D'Avanzo et al., GCN
30261; GECAM detection: Zhao et al., GCN 30264; Fermi-LAT detection: Axelsson et
al., GCN 30270; Afterglow detections: Lipunov et al., GCN 30259; D'Avanzo et
al., GCN 30261; Lipunov et al., GCN 30262; Jelinek et al., GCN 30263; Kong, GCN
30265; Pellegrin et al., GCN 30268; Perley, GCN 30271; Zheng & Filippenko, GCN
30273; Redshift: de Ugarte Postigo, GCN 30272) with the 2-m Liverpool Telescope
located in La Palma, Spain using IO:O camera. The observation started at
02:57:49 UT on June 20, 2021 (t-t0 = 2.97 hours). We obtained 60x45 seconds
exposures in r'. The afterglow is clearly detected in each image. Comparing
to 33 check stars from the PanSTARRS catalogue we derived the decay starting with

r' = 17.91 +- 0.01 mag

and ending at 03:45:43 UT (t-t0 = 3.77) hours with

r' = 18.10 +- 0.02 mag

Magnitudes are given in AB photometric system. These values have not been
corrected for Galactic extintion.