GCN Circular 3176
Subject
GRB 050401: VLT spectroscopic redshift
Date
2005-04-03T19:59:02Z (19 years ago)
From
Jens Hjorth at U.Copenhagen <jens@astro.ku.dk>
Johan P. U. Fynbo, Brian L. Jensen, Jens Hjorth (Niels Bohr Institute),
Klaas Wiersema, Rhaana Starling (U. Amsterdam), Paul Vreeswijk (ESO),
Evert Rol, Andrew Levan (U. Leicester), Sara Ellison (U. Victoria),
Nicola Masetti (IASF-Bologna) report on behalf of a larger collaboration:
"Using FORS2 on the Very Large Telescope we have obtained spectra of the
afterglow of GRB 050401 (GCN 3161, 3162, 3163) on 2005, April 2. We detect
several absorption lines consistent with two absorption systems at redshifts
z = 2.50 and z = 2.90. The likely redshift of GRB 050401 is hence z = 2.90.
For a standard cosmology (H_0 = 70 km/s/Mpc, Omega_m = 0.3, Omega_w = 0.7,
w = -1) the Swift fluence (GCN 3173) corresponds to an isotropic energy
release of 2.6 x 10^53 erg.
We thank Paul Price for providing a finding chart for the optical afterglow
and the ESO staff for excellent support."