[vsnet-grb-info 5133] GRB 070714B: host galaxy spectroscopic redshift

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6836
SUBJECT: GRB 070714B: host galaxy spectroscopic redshift
DATE:    07/10/02 00:36:25 GMT
FROM:    John Graham at STScI  <graham at stsci.edu>

J. F. Graham (STScI/JHU), A. S. Fruchter (STScI), A. J. Levan (U. 
Warwick), M. Nysewander (STScI), N. R. Tanvir (U. Leicester), T. Dahlen 
(STScI), D. Bersier (Liverpool John Moores U.), A. Pe'er (STScI) report 
on behalf of a larger collaboration:

Gemini Nod & Shuffle spectroscopy on the host of GRB 070714B shows a 
single emission line at 7165 A.  A photometric redshift based on Gemini 
grizJHK observations with GMOS and NIRI strongly implies that this is 
the 3727 A [O II] line.  This places the host at a redshift of z=.92

The Swift BAT discovery data show the burst to have had a short, hard 
main component of three seconds duration followed by a soft, longer 
duration tail (Sakamoto et al. GCN 6623).  The main component also shows 
a small spectral lag (Norris et al. GCN 6631).  Both of these 
observations are consistent with GRB 070714B being a short GRB.  This 
then would be the highest spectroscopically confirmed redshift of a 
short burst.

The observed fluence of 7.2 x 10^-7 erg/cm^2 (Barbier et al. GCN 6638) 
at a redshift of z=.92 corresponds to an isotropic energy release of 
Eiso = 1.6 x 10^51 erg.