GCN Circular 12763
Subject
GRB111228A: TNG spectroscopy analysis
Date
2011-12-29T12:36:46Z (12 years ago)
From
Dino Fugazza at INAF-OAB <dino.fugazza@brera.inaf.it>
E. Palazzi (INAF-IASFBo), D. Fugazza (INAF-OAB), S. Piranomonte
(INAF-OAR) on behalf of a larger collaboration report:
The afterglow of GRB 111228A (Ukwatta et al. GCN 12737) was observed
with the DOLORES instrument mounted at the Telescopio Nazionale Galileo
on La Palma, Canary Islands. Starting on December 29.1200 (~11 hour
after the burst), a series of three spectra of 1800s each were secured
with LR-B grism (range 3500-8000 Angstroms).
Preliminary reduction of the spectra reveals absorption features that we
identify with the following absorption lines:
Lines ID Lambda_observed
(Angstroms)
FeII_2344.21 4019.83
FeII_2374.46 4073.40
FeII_2382.76 4088.32
FeII_2585.65 4436.05
FeII_2600.17 4460.64
MgII_2795.50 4795.65
MgII_2802.70 4808.58
MgI_2852.96 4891.53
CaII_3933.68 6756.61
CaII_3968.49 6807.44
The derived redshift is z=0.7156 � 0.0005 which confirms the results
obatined by Dittman et al. (GCN 12759) and Cucchiara et al (GCN 12761).
In addition to the GRB afterglow we observed the SDSS galaxy reported by
Guver (GCN 12741). We detect many emission lines (OII_3726+3728, Hbeta,
OIII_4958, OIII_5006, Halpha) at a common redshift of 0.218 � 0.001
which is in agreement with the reported photometric redshift. This
galaxy is therefore not related to the GRB.
We acknowledge the excellent support from the TNG staff, in particular
Walter Boschin and Gianni Tessicini
[GCN OPS NOTE(22jan12): Per author's request, the affilation was changed
from "U.Milano-Bicocca,INAF/Brera" to "INAF-OAB".]