TITLE:   GCN CIRCULAR
NUMBER:  17710
SUBJECT: GRB 150413A: Refined redshift
DATE:    15/04/16 20:59:00 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI) and L. Tomasella (INAF-OAPd) 
report:

We have reanalysed the spectra of the afterglow of GRB 150413A (Markwardt 
et al. GCN 17688, Ivanov et al. GCN 17689) obtained by the Asiago Transient 
Classification Program (Tomasella et al. 2014, AN, 335, 841) with the Asiago 
1.82 m Copernico Telescope +AFOSC (Tomasella et al. ATel 7391). In addition 
to the Ly-alpha feature already reported, we identify absorption features of SiII, 
SiII*, CII, SiIV, CIV, FeII and AlII at a common redshift of 3.139+/-0.003, slightly 
lower than previously reported by Sanchez-Ramírez (GCN 17697) and by 
Tomasella et al. (ATel 7391). In addition we report a tentative detection of a MgII 
intervening absorber at z=0.950+/-0.003.