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GCN Circular 13221

GRB 120404A : TNT optical observation
2012-04-05T00:44:27Z (12 years ago)
L.P. Xin at NAOC <>
L.P. Xin, J. Y.Wei, Y.L. Qiu, J. Wang,  J.S. Deng, 
C. Wu,  X. H. Han on behalf of EAFON report:
We began to observe GRB 120404A (Stratta et al., GCN Circ. 13208)
with Xinglong TNT telescope in R-band at 19:33:05(UT),   6.7 hours after 
the burst. The optical counterpart (Stratta et al., GCN Circ. 13208, Guidorzi et al. GCN Circ. 13209) 
was marginal detected with a brightness of 20.3 +/- 0.2 mag 
calibrated to USNO B1.0 R2 mag, at the mean time of 7.4 hours after the burst.

Combined with the report by Guidorzi et al. ( GCN Circ. 13209 ), the brightness of this burst
decayed by 1.5 magnitude in R-band during 4 min and 7.4 hour after the burst,
corresponding to a shallow decay index of about 0.3 during this phase. 
Further observations are encouraged. 

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For more information about Xinglong GRBs Follow-up
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We thank Liang Ma for performing these observations.
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