[vsnet-grb-info 16932] GRB 150818A: Spectroscopic confirmation of the SN from GTC

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18213
SUBJECT: GRB 150818A: Spectroscopic confirmation of the SN from GTC
DATE:    15/08/31 17:49:21 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte at iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), Z. Cano (U. Iceland), 
D. A. Perley (DARK/NBI), S. Schulze (PUC, MAS), D. Xu (NAOC/CAS), 
R. Sanchez-Ramirez (IAA-CSIC), D. Malesani (DARK/NBI), G. Lombardi 
(GRANTECAN, IAC, ULL), and A. Garcia (GRANTECAN), R. Scarpa 
(GRANTECAN) report on behalf of a larger collaboration:

We observed the counterpart of GRB 150818A (D'Elia et al. GCN 18152; 
Marshall et al. GCN 18155; McCauley et al. GCN 18161; Mazaeva et al. 
GCN 18175; Sanchez-Ramirez et al. GCN 18177; Mazaeva et al. GCN 
18182, GCN 18189, GCN 18205; Schulze et al. GCN 18179) with the 
10.4 m GTC telescope (+OSIRIS) on the 29th August 2015 (11.4 days 
after the burst). The observation consisted of 3x900 s spectroscopy using 
the R1000B grism (3700-7800 AA coverage with a resolution of ~1000) 
plus g-, r- and i-band imaging. We detect a point-like source at the location 
of the afterglow superposed on top of an extended source. 

The combined spectrum shows broad features typical of a broad-lined 
Type Ic SN near maximum light, thus confirming the detection of a rising 
supernova proposed by Mazaeva et al. (GCN 18205). The spectrum also 
shows narrow emission features of [OII], [OIII] and H-beta at z=0.282 
(Sanchez-Ramirez et al. GCN 18177).