GCN Circular 17738
Subject
GRB 150423A: VLT detection
Date
2015-04-23T20:20:49Z (9 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann (TLS Tautenburg), T. Kruehler (ESO Chile), S. Klose (TLS
Tautenburg) and J. Greiner (MPE Garching) report:
We obtained a photometry sequence in BVRIz with VLT FORS2 of the optical
afterglow (Varela et al., GCN # 17729, # 17732; Perley, GCN # 17733;
Littlejohns et al., GCN # 17736) of the short GRB 150423A (Swift-638808,
Pagani et al., GCN # 17728).
Observations started on April 23, 2015, 08:02:19 UT, 94 minutes after the
GRB. Seeing was 1".0 and airmass was 1.7.
The afterglow is clearly detected in BVR. Analysis of Iz is pending.
We find Rc = 22.8 +/- 0.1 in the first image (calibrated against SDSS
standard stars transformed to Rc) and find it fades by approximately 0.4
magnitudes in the course of an hour (see also Perley, GCN # 17733;
Littlejohns et al., GCN # 17736).
We are indebted to Jonathan Smoker and Fernando Selman for VLT UT1 support.