GCN Circular 9409
Subject
GRB 090519: VLT spectroscopic redshift
Date
2009-05-20T08:54:17Z (15 years ago)
From
Paolo D'Avanzo at INAF-OAB <paolo.davanzo@brera.inaf.it>
A. J. Levan (Univ. Warwick), P. Jakobsson (U. Iceland), C. C. Thoene
(INAF/OAB), P. D'Avanzo (U. Bicocca & INAF/OAB), A. De Cia (U. Iceland),
J. P. U. Fynbo, J. Hjorth, D. Malesani (DARK/NBI), D. Fugazza (INAF/OAB),
N. R. Tanvir (U. Leicester) report on behalf of a larger collaboration:
Using FORS2 on the ESO Very Large Telescope, we have obtained
low-resolution spectra (3 x 30 min) of the optical afterglow of GRB
090519 (Perri et al., GCN 9400; Thoene et al., GCN 9403) with the grism
300V, covering the wavelength range 3500-9200 AA. In the acquisition
image the afterglow has a magnitude of R ~ 23.5. The first spectrum
was taken approximately 4 hours after the burst.
In a preliminary analysis we detect a break around 4400 AA and strong
absorption features around 5000 AA and 5900 AA. We interpret these
features as the Lyman limit, Lyman-beta and Lyman-alpha at a redshift of
z = 3.85. This is in agreement with the photometric redshift reported by
Rossi et al. (GCN 9408).
We thank the Paranal staff for excellent support, in particular Gianni
Marconi, Kieran O'Brien and Patricia Guajardo.
[GCN OPS NOTE(20may09): Per the original first-author's (CCT) request,
the author list was changed.]