GCN Circular 10752
Subject
GRB 100513A: Gemini/GMOS Spectroscopic Redshift
Date
2010-05-13T07:39:53Z (14 years ago)
From
S. Bradley Cenko at Caltech <cenko@srl.caltech.edu>
S. B. Cenko, D. A. Perley, A. N. Morgan, C. R. Klein, J. S. Bloom, N. R.
Butler, and B. E. Cobb (UC Berkeley) report on behalf of a larger
collaboration:
We have obtained an optical spectrum of the afterglow (Morgan et al., GCN
10747) of GRB 100513A (Baumgartner et al., GCN 10746) with the Gemini
Multi-Object Spectrograph mounted on the 8 m Gemini North
telescope. Observations began at 6:13 UT on 13 May (~ 4.1 hours after the
GRB) and cover the wavelength range from 6000-10000 A.
The spectrum exhibits a strong break at approximately 7000 A which we
associate with a damped Ly-alpha system at z ~ 4.8. We identify a series
of narrow absorption features redward of Ly-alpha, including O I 1302, Si
II 1304, C II 1334, C II* 1335, Si IV 1393, 1402, Si II 1526, and C IV
1548, 1550 all at a common redshift of z = 4.772. The presence of C II*,
along with Ly-alpha forest continuum emission blueward of 7000 A, strongly
suggest this is the redshift of the GRB host galaxy.
The presence of the Ly-alpha break at 7000 A further explains the
relatively faint R-band afterglow observed by Perley et al (GCN 10750;
also Updike et al., GCN 10748).
We wish to thank the entire Gemini staff, in particular Richard McDermid,
for the prompt execution of these observations.