L.P. Xin, Z. X. Ling, Y.L. Qiu, J.Y. Wei, J. Wang, J.S. Deng,
C. Wu, X. H. Han, J.Y. Hu on behalf of EAFON report:
We began to observe GRB100805A (Hoversten E. A. et al., GCN 11047 )
with Xinglong TNT telescope at 12:29:52 (UT), 8.28h after
the burst. Nine R band images were obtained. The exposure time for
each frame is 600 sec. The afterglow (Hoversten E. A. et al., GCN 11047)
with a brightness of 21.3+/-0.2 mag was detected with the combined
9*600s white-band data at the mean time of 8.95h after the burst.
The reference star is a nearby USNO-B1.0 star with a coordinates
of 19:59:33.3, +52:37:54.0, and a brightness of R2=17.41 mag.
Combining TNT data and other data reported in the previous GCN circulars
(Cenko, GCN 11050, GCN 11051;Gomboc et al. GCN11052;
Nissinen et al. GCN 11056; Gorosabel et al. GCN 11060; Wren et al. GCN 11064 ),
we infer that the brightness of OT was decaying with a power-law decay index of
alpha~0.73 from 100sec to 8.9h after the burst, consistent with
the reports of Cenko, GCN Circ. 11051 and Gomboc et al. GCN 10052.
This message may be cited.
For more information about Xinglong GRBs Follow-up
observations, please visit the website: