[vsnet-grb-info 16242] GRB 150301B: X-shooter spectroscopy

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17523
SUBJECT: GRB 150301B: X-shooter spectroscopy
DATE:    15/03/02 02:07:10 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte at iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), T. Kruehler (ESO), 
H. Flores (GEPI/Obs. de Paris), and J.P.U. Fynbo (DARK/NBI) 
report on behalf of a larger collaboration:

We observed the afterglow of GRB 150301B (Lien et al. GCN 17515, 
Buckley et al. GCN 17518, Kann et al. GCN 17522) with X-shooter at the 
Very Large Telescope (Paranal Observatory, Chile). Observations started 
at 00:45 UT (5.12 hr after the burst), and consisted of 6x600 s exposures 
covering the spectral range between 3 000 and 18 000 Angstroms.

In the acquisition image the afterglow is detected with R(Vega) = 21.0 mag, 
as compared to stars of the USNOB-1.0 catalogue.

On a preliminary reduction we detect a weak continuum with absorption 
features of FeII, MgII and MgI at a common redshift of z = 1.5169, which 
we suggest as the redshift of the GRB.

We acknowledge the excellent support provided by Paranal staff, and in 
particular Andrea Mehner, Tayyaba Zafar, and Marcelo Lopez.