[vsnet-grb-info 4209] GRB 070110: VLT absorption redshift

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6010
SUBJECT: GRB 070110: VLT absorption redshift
DATE:    07/01/11 11:23:49 GMT
FROM:    Daniele Malesani at Niels Bohr Inst,Dark Cosmology Center  <malesani at astro.ku.dk>

A.O. Jaunsen (Univ. Oslo), D. Malesani, J.P.U. Fynbo, J. Sollerman
(DARK/NBI), P.M. Vreeswijk (ESO), report on behalf of a larger
collaboration.

We observed the optical afterglow of GRB 070110 (Krimm et al., GCN 6005;
Roming et al., GCN 6009) with the ESO VLT equipped with FORS2.
Observations started on 2007 Jan 11.04 UT (17.6 hr after the GRB). Three
1800-s spectra were acquired in the range 3800-8500 AA.

Based on the detection of a DLA and several metallic lines (among which
SiII 1260, SiIV 1394,1403, CIV 1548,1551 and many others), we infer a
redshift z = 2.352 +- 0.001. We also detect Lyalpha in emission
superimposed on the DLA trough. We caution that the wavelength calibration
has been performed using archival lamps.

We acknowledge the excellent support from the ESO/Paranal staff.