[vsnet-grb-info 25364] GRB 200325B: Tautenburg observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27464
SUBJECT: GRB 200325B: Tautenburg observations
DATE:    20/03/28 20:01:16 GMT
FROM:    Sylvio Klose at TLS Tautenburg  <klose at tls-tautenburg.de>

S. Klose, B. Stecklum, A. Nicuesa Guelbenzu, S. Melnikov, and F. Ludwig
(all Tautenburg) report:

We observed the field of GRB 200325B (Ferni GBM team, GCN 27441) with the 
Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6k x 6k CCD 
camera and the wide V-band filter (VB). The transmission curve of this 
filter closely follows the Gaia GBP filter. Observations were performed 
during several epochs starting 1.2 days after the burst.

The optical transient discovered by the MASTER Global Robotic Net (Lipunov 
et al., GCN 27446) is clearly detected (see also Pozanenko et al., GCN 
27452; Belkin et al., GCN 27455; Strausbaugh et al., GCN 27456; D'Avanzo 
et al., GCN 27457). Aperture photometry was performed using several Gaia 
DR2 stars in the field. Between dt = 1.2 and 2.4 days the optical 
transient was fading by 1.3 mag. During our last observation (2.4 days 
post burst) it had reached VB = 20.7 +/- 0.2 mag.