[vsnet-grb-info 24439] GRB 191221B: Swift/UVOT redshift

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26538
SUBJECT: GRB 191221B: Swift/UVOT redshift
DATE:    19/12/22 01:33:28 GMT
FROM:    Paul Kuin at MSSL  <npkuin at gmail.com>

N. P. M. Kuin (UCL-MSSL) reports on behalf of the Swift/UVOT team:

The Swift/UVOT obtained a 49s grism spectrum of GRB 191221B
242 s after the BAT trigger (Laha et al., GCN Circ. 26534).
The spectrum shows a clear break at 2008 Angstrom, suggesting
a redshift of z=1.19. At that redshift, the line of He II 1640A is well
defined
and N II 2143A is present, as well as possibly N V at 1243 A.