GCN Circular 27571
Subject
GRB 200412B: Xinglong TNT optical observations
Event
Date
2020-04-14T04:22:19Z (6 years ago)
From
Liping Xin at NAOC, SVOM <xlp@nao.cas.cn>
L. P. Xin, X. F. Wang, J. Zheng, Y. L. Qiu, J. Y. Wei, J. Wang,
L. H. Li , C. Wu, X. H. Han and J. S. Deng, report:
We began to observe GRB 200412B (The Fermi GBM team,
GCN 27547; Longo et al. GCN 27557)
with Xinglong TNT telescope at 18:09:54 (UT), 13th. Apr. 2020,
about 33 hours after the burst.
10 x 300 sec R band images were obtained.
The optical afterglow (Lipunov et al., GCNs 27555, 27556; Kumar et al., GCN
27564; Belkin et al., GCN 27566, Stecklum et al., GCN 27567,
Moskvitin GCN 27570) is clearly detected in individual
images with the brightness of R = 20.0 +/- 0.1.
The photometry is based on R2 magnitudes of nearby USNO-B1 stars.
With the reports from (Kumar et al., GCN
27564; Belkin et al., GCN 27566, Stecklum et al., GCN 27567,
Moskvitin GCN 27570), the brightness is fading with a slope of -1.5
for a single power law (t~t^a) from 10 hours to 39 hours after the burst trigger.