TITLE: GCN CIRCULAR
NUMBER: 7286
SUBJECT: GRB 080210: VLT redshift
DATE: 08/02/10 12:22:25 GMT
FROM: Pall Jakobsson at U Hertfordshire
Pall Jakobsson (U. Hertfordshire), Paul M. Vreeswijk, Daniele Malesani
(DARK, NBI), Andreas O. Jaunsen (U. Oslo), Johan P. U. Fynbo, Jens
Hjorth (DARK, NBI) and Nial R. Tanvir (U. Leicester) report on behalf
of a larger collaboration:
Using FORS2 on the Very Large Telescope, we have obtained a 10 min
spectrum (grism 300V) of the optical afterglow of GRB 080210 (Grupe et
al., GCN 7281).
The acquisition image shows the UVOT optical afterglow candidate to
have R = 18.8 on Feb 10.351 UT (0.597 hours after the GRB) using
photometric zeropoints from the ESO webpages. We also obtained an
R-band image at 1.65 hours after the GRB indicating a decay index of
0.76 +/- 0.04.
The spectrum is rich in absorption features, including Ly-alpha, Si II,
C II, Si IV, C IV, Fe II and Al II, corresponding to a redshift of
z = 2.641. This is consistent with the redshift upper limit (z < 3.5)
reported by GROND (Kuepcue Yoldas et al., GCN 7283). There is also a
tentative detection of Ly-alpha in emission superimposed on the DLA
trough.
We thank the Paranal staff for excellent support, especially Paul
Lynam.