TITLE:   GCN CIRCULAR
NUMBER:  17278
SUBJECT: GRB 150101B: potential host galaxy redshift by GTC
DATE:    15/01/04 12:07:07 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

A. J. Castro-Tirado (IAA-CSIC, ISA-UMA), R. Sanchez-Ramirez, J.
Gorosabel (IAA-CSIC, UPV/EHU) and R. Scarpa (GTC), on behalf of a
larger collaboration, report:

Following the detection of the short-duration GRB 150101B by Swift/BAT
(Cummings et al. 2015, GCNC 17267) and Fermi (Stanbro et al. GCNC 17276),
we have obtained an optical spectrum with the 10.4 m GTC (+OSIRIS)
starting on Jan 4, 5:41 UT (i.e. 38.1 hr postburst), covering the
3700-10000 A wavelength range, under poor weather conditions (passing
clouds) and bad (>2.5”) seeing. The slit included the position of the
proposed optical afterglow (Fong et al. GCNC 17271) as well as the
putative host galaxy also detected by Swift/UVOT (Cummings et al. GCNC
17258). We detect a faint emission line consistent with [OII] at z =
0.093, which we propose to be that of the potential host galaxy. If the
association is confirmed, this would make of GRB 150101B the nearest
short-duration GRB found to date. Observations at all wavelengths are
encouraged.