J. Gorosabel (IAA-CSIC/UPV-EHU), A. de Ugarte Postigo (IAA-CSIC/DARK-NBI),
C. Thoene (IAA-CSIC), D. Perley (Caltech), A. Garcia Rodriguez (GTC),
report on behalf of a larger collaboration:
We observed the optical candidate iPTF14eag of the Fermi GRB140808A
(Singer et al. GCN 16668; Zhang, GCN 16669; Page et al. GCN 16670) with
the 10.4m GTC (+OSIRIS). Spectroscopic observations were carried out at
21:43:48--22:29:36 UT (20.8-21.9 hours post burst).
Three 900s spectra were obtained with the R1000B grism, covering the range
between 3630 and 7500 A, at a resolution of ~1000. A preliminary reduction
based on archival calibration lamps, reveals a strong DLA and several
absorption metallic lines (CII, SiIV, SiII, CIV, AlII) consistent with a
common redshift of z=3.29, which we identify as the redshift of the GRB.