[vsnet-grb-info 8316] GRB090817: Keck/LRIS Spectroscopy

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9841
SUBJECT: GRB090817: Keck/LRIS Spectroscopy
DATE:    09/08/26 08:22:47 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko at srl.caltech.edu>

S. B. Cenko, L. M. Walkowicz (UC Berkeley), M. M. Kasliwal, V. Bhalero, S.
R. Kulkarni, F. A. Harrison (Caltech), I. Arcavi (Weizmann Institute) and
W. H. Baumgartner (GSFC/UMBC) report on behalf of a larger collaboration:

We have obtained a spectrum of the putative host galaxy of GRB09817
(Holland et al., GCNs 9831 and 9834) with the Low Resolution Imaging
Spectrometer mounted on the 10 m Keck I telescope.  Our spectra were taken
in twilight conditions at Aug 25.55 UT and cover a wavelength range from
3500 - 9000 A.

After correcting for the large Galactic extinction, the source exhibits
a blue continuum with superposed absorption features from the H Balmer
series (H-alpha, -beta, -gamma, and -delta) and Ca (H+K and the NIR
triplet), all consistent with their rest wavelengths.  As suggested by
Halpern and Ruan (GCN 9837), the object is therefore a foreground star
(likely a hot, ~ A-type) and likely unrelated to GRB090817.