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GCN Circular 606

Subject
GRB 000301C: Optical Spectrum and Redshift
Date
2000-03-10T13:52:14Z (24 years ago)
From
LIfan Wang at U.Texas <lifan@astro.as.utexas.edu>
Feng, M., Wang, L., and Wheeler, J. C., University of Texas at Austin report:

We obtained a low resolution (resolving power about 70) spectrum of 
GRB 000301c with the 2.7 meter telescope at McDonald Observatory on 2000 
March 3.47. The total exposure time was 3900 seconds with wavelength 
coverage from 318 nm to 589 nm. The low S/N (about 2-4) spectrum can be 
fitted with a power law of spectral index beta = -1.1 witn no obvious
breaks after correcting for interstellar extinction assuming R = 3.1, 
E(B-V) = 0.05 (cf GCN 585). The flux level is around 2.5E-17 ergs/cm2/sec/A. 
This puts any possible Lyman break at wavelengths shorter than 318 nm.  
The object is thus at a redshift lower than 2.5. This is consistent with 
the report by Smette et al. (GCN 603).

The spectrum may reveal two absorption features at 336.0 nm and 
352.2 nm.  If identified with Lyman alpha, the redshifts of these features 
are 1.76 and 1.89.  The data also show another absorption feature at 
367.1 nm, but with even lower confidence level.  This feature yields 
a redshift of 2.02 if identified with Lyman alpha.  Another possible
feature is an absorption at 405.8 nm which might be identified with 
C II 133.5 nm at a redshift of 2.04.

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