[AAVSO-HEN] GRB 090926B: VLT spectroscopy

[grb at aavso.org]

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TITLE:   GCN CIRCULAR
NUMBER:  9947
SUBJECT: GRB 090926B: VLT spectroscopy
DATE:    09/09/27 11:21:59 GMT
FROM:    Pall Jakobsson at U of Iceland  <pja at raunvis.hi.is>

Johan P. U. Fynbo, Daniele Malesani (DARK/NBI), Pall Jakobsson
(U. Iceland) and Valerio D'Elia (ASDC and INAF/OAR) report on
behalf of a larger collaboration:

We observed the afterglow of GRB 090926B (Grupe et al, GCN 9935;
Morii et al., GCN 9943). Using FORS2 on the Very Large Telescope,
we have obtained 3*30 min spectra (300V grating) of the optical
afterglow candidate (Malesani et al., GCN 9944). Observations
commenced roughly 8 hours after the burst.

The combined spectrum shows an emission line, presumably
corresponding to [O II] 3727 at z = 1.24. At his redshift we
find several other absorption features, including Mg II, Fe II
and Al III. Hence, we interpret the spectrum as a combination
of the GRB afterglow and the host galaxy.

We acknowledge excellent support from the ESO observing staff,
in particular Yuri Beletsky and Stephane Brillant.