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GCN Circular 3710

GRB050730: confirmation of redshift
2005-07-31T02:25:13Z (19 years ago)
Evert Rol at U.Leicester <>
E. Rol (U. of Leicester), R. Starling, K, Wiersema (U. of Amsterdam),
P. Vreeswijk (ESO), Andrew Levan (U. of Leicester), Neil O'Mahony
(ING), C. Tadhunter, Javier Rodriguez (Sheffield University), Rosa
M. Gonzlez Delgado (IAA CSIC) report for a larger collaboration:

We have observed the optical afterglow (GCN 3705) of GRB 050730 (GCN
3704) using the ISIS spectrograph on the William Herschel Telescope at
the Observatorio del Roque de los Muchachos on La Palma.

The mid-point of our observations is at 0.143 days after burst. We
obtained 1260+1800 seconds exposures in both the 300B and 300R grisms
with a 2.5 arcsec slit. Though data were taken under high airmass, a
high signal to noise spectrum was obtained.

We find strong damped Ly alpha and Ly beta systems, as well as a
multitude of metallic lines in the spectrum, from which we determine a
redshift of 3.97, confirming the redshift reported in GCN 3709.

We thank the staff of the WHT for outstanding support for these
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