[vsnet-grb-info 7587] GRB090417B: Xinglong TNT optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9142
SUBJECT: GRB090417B: Xinglong TNT optical upper limit
DATE:    09/04/18 05:03:56 GMT
FROM:    L.P. Xin at NAOC  <xlp at bao.ac.cn>

L. P. Xin, X. F. Wang, W. K. Zheng, Y. L. Qiu, J. Y. Wei,
J. Wang, J. S. Deng, Y. Urata and J. Y. Hu
on behalf of EAFON report:

We have observed GRB 090417B (Sbarufatti et al., GCN 9135)
with Xinglong TNT telescope from  Apr.17,15:34:38(UT),
14.5 min after the burst. The weather was cloudy.
After combined  white and R band images, 
no new source was found in our combined images. 
The 3 sigma upper limits derived from USNO-B1.0 R2 
magnitudes were shown as following:
--------------------------------------------------------
MeanTime exposure  Band   Mag    UpperLimit?   coadded?
--------------------------------------------------------
16.5min    8*40s   white  20.1       yes          yes
1.63hr    29*300s   R     21.6       yes          yes
-------------------------------------------------------

We also notice that in the location of XRT error circle,
a extended object was likely to be present,
as found by Fynbo et al (GCN 9140).
However, the S/N is very low that we could not make sure.

This message may be cited.

For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org/grb/