GCN Circular 3732
Subject
GRB 050730: Preliminary Analysis of MIKE Spectrum
Date
2005-08-02T06:00:34Z (19 years ago)
From
Jason Prochaska at UCO/Lick Obs <xavier@ucolick.org>
J. X. Prochaska (UCO/Lick), H.-W. Chen (MIT), J. S. Bloom (UCB),
J. O'Meara (MIT), S. M. Burles (MIT), I. Thompson (OCIW)
report on behalf of the GRAASP collaboration:
"We have performed preliminary analysis of our MIKE spectrum of
the afterglow of GRB 050730. A profile fit to the Lya and Lyb
absorption lines of the sightline through the host galaxy gives
N(HI) = 22.15 +/- 0.05. The simple and narrow metal-line profiles
give a redshift z=3.96855 +/- 0.00005. We estimate a neutral gas
metallicity of S/H ~ 1/100 solar which is lower than the
mean metallicity of damped Lya system at this redshift. More
strikingly,
we identify fine-structure lines of SiII*, OI*, OI**, and FeII*, the
majority of which are saturated. Also, we identify absorption
features near 6150A which we interpret as the NV absorption doublet.
Finally, we identify an intervening damped Lya system at
z=3.5650 +/- 0.0001 with log N(HI)= 20.30 +/- 0.15 and low metallicity
as well as a z=1.773 MgII absorber.
A full analysis is underway.
Figures can be found at this following site:
http://www.graasp.org/Data/index.html