GCN Circular 10684
Subject
GRB 100425A: VLT/X-shooter redshift
Date
2010-04-25T12:27:35Z (14 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
P. Goldoni (APC/Univ. Paris 7 and SAp/CEA), H. Flores (Paris Obs.), D.
Malesani (DARK/NBI), A. J. Levan (Univ. Warwick), N. R. Tanvir (Univ.
Leicester), J. P. U. Fynbo (DARK/NBI), report on behalf of a larger
collaboration:
We observed the optical afterglow of GRB 100425A (Grupe et al., GCN
10673; Malesani et al., GCN 10680; Olivares et al., GCN 10683) with th
ESO VLT equipped with the X-shooter spectrograph. Four spectra lasting
10 minutes each were obtained, covering the spectral range 3000-25000
AA, starting on 2010 April 25, at 6:53 UT (4.0 hr after the GRB).
We detect the traces of both objects lying within the XRT error circle.
Preliminary inspection of the spectrum of the afterglow reveals several
absorption features which we interpret as due to Mg II and Fe II, at a
common redshift z = 1.755.
We caution that the data reduction was carried out using archival
calibration files. We acknowledge a particularly helpful and attentive
support from the ESO staff in Paranal, especially Jonathan Smoker,
Lorena Faundez, Manuel Olivares and Steffen Mieske.