[vsnet-grb-info 19198] GRB 170311A: VLT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20858
SUBJECT: GRB 170311A: VLT observations
DATE:    17/03/13 12:54:51 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani at dark-cosmology.dk>

D. Malesani (DARK/NBI), H. Flores (GEPI/Paris obs.), A. J. Levan (Univ. 
Warwick), D. Xu (NAOC/CAS), N. R. Tanvir (Univ. Leicester), and J. P. U. 
Fynbo (DARK/NBI), report:

We observed the field of GRB 170311A (Cummings et al., GCN 20846) with 
the VLT/UT2 (Kueyen), using the acquisition camera of the X-shooter 
spectrograph. Observations started approximately on March 11.366 UT, 
that is around 38 min after the GRB trigger. Imaging was carried out 
using the SDSS z filter.

No source is detected within or close to the UVOT-enhanced XRT position 
(Osborne et al., GCN 20850), down to a 3-sigma limiting magnitude z = 21 
AB, calibrated against nearby stars from the Pan-STARRS catalog 
(Chambers et al. 2016, arXiv: 1612.05560). Our result is consistent with 
other reports (e.g., Wiseman & Schady, GCN 20853).

We acknowledge excellent support from the ESO observing staff at 
Paranal, in particular Marcelo Lopez, Joe Anderson, and George Hau. We 
also acknowledge the team of the Gaia-ESO survey (ESO program 
197.B-1074, PI Gilmore), for generously and consistently accepting to 
carry out ToO observations during their allocated nights.