[vsnet-grb-info 21530] GRB 180106A: update of the Xinglong-2.16m spectroscopy

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23629
SUBJECT: GRB 180106A: update of the Xinglong-2.16m spectroscopy
DATE:    19/01/07 05:25:15 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu at nao.cas.cn>

D. Xu, Z.P. Zhu, Y. Wang, J.B. Zhang (NAOC), J.H. Liu, X. Zhang (XAO) 
report:

We have re-reduced the 3600s+3000s spectra taken from the Xinglong-2.16m 
telescope (Zhu et al., GCN 23623), with the calibration frames taken in 
the same night. The Signal-to-Noise of the spectrum increased compared 
with the previous 3600s one, and the resolution is not high due to 
seeing~2.0".

We only consider relatively prominent absorption features and thus only 
six features are left, which can be interpreted as Fe II 1547.62, 
1550.19, 2585.88, 2599.40, and Mg II doublet 2795.53, 2802.71 
(wavelength in air), at an updated and consistent redshift of z=1.86.