[vsnet-grb-info 14608] GRB 140304A: 10.4m GTC redshift z = 5.39

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15922
SUBJECT: GRB 140304A: 10.4m GTC redshift z = 5.39
DATE:    14/03/04 22:01:48 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct at iaa.es>

S. Jeong, R. Sánchez-Ramírez (IAA-CSIC), A. J. Castro-Tirado (IAA-CSIC,
UMA), J. Gorosabel (EHU-UPV, IAA-CSIC), M. Jelinek, J. C. Tello, P.
Ferrero, O. Lara-Gil, R. Cunniffe (IAA-CSIC), D. Pérez-Ramírez (U. Jaén),
S. Guziy (Nikolaev Univ.), J. M. Castro Cerón (ESAC), A. Fernández-Soto
(UV), J. Cepa (IAC), M. A. Rivero and G. Gómez-Velarde (GTC), on behalf of
a larger collaboration, report:

“Following the detection of the optical afterglow (Gorbovskoy et al. GCNC
15914) to GRB 140304A (Evans et al. GCNC 15915), we have obtained an
optical spectrum with the 10.4 m GTC (+OSIRIS) starting aprox. 8.2 hr
postburst, covering the 5700-10000 wavelength range. The continuum is
detected only redwards of aprox. 7750 A, with several absorption metallic
lines (N V, Si II and Si IV amongst others) at a common redshift of z =
5.XX which we propose to be the redshift of GRB 140304A. This is
consistent with the Swift/UVOT upper limits (Marshall et al. GCNC 15920)
and the NOT optical observation (de Ugarte Postigo et al. GCNC 15921).”