TITLE:   GCN CIRCULAR
NUMBER:  24762
SUBJECT: GRB 190604B: VLT Afterglow Detection
DATE:    19/06/06 16:39:16 GMT
FROM:    Alexander Kann at IAA-CSIC  <kann@iaa.es>

L. Izzo, D. A. Kann (both HETH/IAA-CSIC), D. B. Malesani (DTU Space), D. 
Hartmann (Clemson University), A. de Ugarte Postigo (HETH/IAA-CSIC, 
DARK/NBI), and N. R. Tanvir (Univ. Leicester) report on behalf of the 
Stargate Consortium:

We observed the field of GRB 190604B (Page et al., GCN 24742) with 
X-shooter mounted on the ESO VLT UT2 (Kueyen). Images were obtained in 
SDSS g'r'z', as well as a deeper 300 s r' exposure, centered at 05:24:16 
UT on June 05, 2019 (0.8483 days after the GRB trigger).

At the position of the UVOT afterglow (Breeveld et al., GCN 24747) and 
within the XRT error circle (Evans et al., GCN 24746), we detect a faint 
source only in the latter image.

Using a recent computation of the X-shooter acquisition camera 
zero-point value, the total number of counts, a seven arcsec radius 
aperture and the exposure time of 300 s, we derive a magnitude of r'(AB) 
= 23.27 +/- 0.09 mag.

Because of source faintness, no spectroscopy was attempted.