[vsnet-grb-info 15162] GRB140606B/iPTF14bfu: Keck detection of an associated supernova

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16454
SUBJECT: GRB140606B/iPTF14bfu: Keck detection of an associated supernova
DATE:    14/06/25 05:24:36 GMT
FROM:    Daniel Perley at Caltech  <dperley at astro.caltech.edu>

D. A. Perley (Caltech), M. L. Graham, A. V. Filippenko (UC Berkeley), 
and S. B. Cenko (GSFC) report:

We acquired a single 1200-second spectrum of iPTF14bfu (Singer et al., 
GCN 16360; Perley et al., GCN 16365), the optical transient associated 
with GRB 140606B (Burns et al., GCN 16363), using the Low Resolution 
Imaging Spectrometer (LRIS) on the Keck I 10-meter telescope.  The 
observation was conducted starting at 13:00 UT on 2014-06-24, 18.4 days 
after the GBM trigger, and covers a wavelength range from 320-1028 
nanometers.

The spectrum shows several broad emission features and a significant 
decrease in flux toward both the blue and red ends.   A comparison with 
SN 1998bw* using superfit (Howell et al. 2005, ApJ 634, 1190) shows a 
good match between the observed features and the spectrum of SN 1998bw 
near maximum light, indicating that the transient has evolved into a 
Type Ic-BL supernova.

* http://www.astro.caltech.edu/~dperley/grb/140606b/140606b_98bw.png