TITLE:   GCN CIRCULAR
NUMBER:  16320
SUBJECT: GRB 140521A : Xinglong TNT upper limit
DATE:    14/05/23 07:50:38 GMT
FROM:    L.P. Xin at NAOC  <xlp@bao.ac.cn>

L. P. Xin,   X. F. Wang,  J. Y. Wei,  Y. L. Qiu, J. S. Deng,  
J. Wang, X. H. Han and C. Wu on behalf of EAFON report:

We began to observe GRB 140521A (Troja et al., GCN 16311)  
with Xinglong  0.8-m TNT telescope at 15:35:50 (UT) , 
92 sec after the burst.

No any optical transient was detected in our single or stacked image.
The 3-sigma upper limit magnitude is about 18.4 mag at the mean time of
7.3 min , calibrated by nearby USNO B1.0 R2 mag.

The message may be cited.