GCN Circular 15571
Subject
GRB 090530: X-shooter redshift
Date
2013-12-03T18:31:28Z (10 years ago)
From
Paolo Goldoni at U.Paris/APC <goldoni@apc.univ-paris7.fr>
P. Goldoni (APC/Irfu - CEA), A. de Ugarte Postigo (IAA - CSIC and DARK/NBI) and J.P.U. Fynbo (DARK/NBI) report on behalf of the X-shooter GRB collaboration :
We reduced with the most recent pipeline the observations of the optical afterglow of GRB 090530 (Cannizzo et al., GCN 9438) made using the ESO VLT equipped with the X-shooter spectrograph. The observations were performed during commissioning with the instrument not fully calibrated. The observations started on 2009-05-30 at 23:56 UT (i.e., 20.63 hr after the burst). A total exposure of 1x900 s + 4x1200 s was obtained, covering the spectral range from ~3000 to ~24000 Ang.
The afterglow is detected in the UVB and VIS arms with a faint continuum. Superposed on the continuum we detected spectral features consistent with MgII, MgI, SiII, FeII and AlIII at a redshift ~1.266 fully consistent with the photometric redshift 1.28 (+0.16, -0.15) (Kruehler et al. 2011, A&A 526, 153).