[vsnet-grb-info 28172] GRB 210619B: CAHA 2.2m photometric monitoring

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30275
SUBJECT: GRB 210619B: CAHA 2.2m photometric monitoring
DATE:    21/06/20 15:53:18 GMT
FROM:    Alexander Kann at IAA-CSIC  <kann at iaa.es>

D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, 
DARK/NBI), M. Blazek, C. Thoene, J.F. Agui Fernandez, Ginger (all 
HETH/IAA-CSIC), and J. I. Vico Linares (CAHA) 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; Blazek et al., GCN 
30274; Redshift: de Ugarte Postigo, GCN 30272) with CAFOS mounted at the 
2.2m Calar Alto telescope (Almeria, Spain). After a weather-induced 
delay, we obtained 80 x 60 s images in Ic. The afterglow is clearly 
detected in each image.

The sequence starts at 01:23 UT and ends at 03:43 UT on 2021-06-20 
(0.05836 to 0.15479 d after burst trigger). Comparing to a single star 
with a magnitude derived from PanSTARRS and transformed following Lupton 
(2005), we find the afterglow decays from Ic (AB) = 16.75 +/- 0.05 mag 
to Ic (AB) = 17.45 +/- 0.05 mag.

Further observations are planned.