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GCN Circular 22320

GRB180111A: Xinglong TNT possible optical detection
2018-01-11T23:20:38Z (6 years ago)
L.P. Xin at NAOC <>
L. P. Xin,   C. Liu,  J. Y. Wei,  Y. L. Qiu, J. S. Deng,  
J. Wang,  X. H. Han, X. M. Meng and C. Wu report:
We began to observe GRB 180111A (Lien et a l., GCN22318)  
with Xinglong  0.8-m TNT telescope at 2018-01-11, 14:43:34(UT),
about 93 sec the burst.
We obtained several white and R-band images.
In any single white band frame, no any new optical transient 
was detected within UVOT circle and XRT circle 
(Lien et a l., GCN22318, Evens et al., GCN 22319) 
down to 18.5 magnitude at the mid time of 113 sec after the burst  .

However, there is a marginal source in the 20*20sec coadded image 
within the XRT circle  (Evens et al., GCN 22319),  whose position is consistent 
with  the location of the reported optical counterpart (Lien et a l., GCN22318). 
The brightness is about 20.0+/-0.3 calibrated by the local USNO B1.0 R2 mag
at the mid time of 300 sec after the burst. 

We are making further analysis for the possible low S/N detection 
since there is a bright star near the GRB location.
The message may be cited.

[GCN OPS NOTE(11jan18):  The latter 'A' was added to the GRB name
in the Subject-line.]
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