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GCN Circular 30774

GRB 210827B: GECAM detection
2021-09-05T15:56:03Z (3 years ago)
Y Q Zhang at IHEP <>
J. C. Liu, S. L. Xiong, X. Y. Zhao, Y. Huang, X. Y. Song, C. Cai, S. Xiao,
S. L. Xie, Y. Q. Zhang, Y. Zhao, Z. W. Guo, C. Zheng, W. C. Xue, C. Y. Li,
C. W. Wang, Q. B. Yi, B. X. Zhang, P. Zhang, W. X. Peng, R. Qiao, D. Y. Guo,
X. B. Li, X. Ma, P. Wang, J. Wang, Z. Zhang, S. J. Zheng, W. Chen, J. J. He, 
G. Y. Zhao, Y. Q. Du, H. Wu, J. Liang, Q. Luo, X. L. Zhang,
L. M. Song, F. J. Lu, S. N. Zhang (IHEP), report on behalf of GECAM team:

During the commissioning phase, GECAM-B was triggered in-flight by a long
burst, GRB 210827B, at 2021-08-27T10:10:16.60 UTC (denoted as T0), 
which was also observed by Fermi/GBM (GCN #30726). 
GECAM alert data was downlinked to the ground through the short message
service of BeiDou Navigation Satellite System (BDS) within ~60 s after T0.

According to the BDS alert data, this burst mainly consists of a broad pulse
with a duration of about 20 s. 

The GECAM light curve could be found here:

Using the automatic on-ground localization pipeline with the BDS alert data, 
GECAM-B localized this burst to the following position (J2000): 
Ra: 307.5 deg 
Dec: -19.2 deg
Err: 3.5 deg (1-sigma, statistical only)
The current systematic error of location is estimated to be several degrees 
which could be minimized by the ongoing calibration.

The GECAM preliminary location could be found here:

GECAM location is consistent with the Fermi/GBM position within the error.

Please note that all GECAM results here are preliminary. The final analysis
will be published in journal papers or GECAM online catalog.

Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor
(GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in
Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time),
which was funded by the Chinese Academy of Sciences (CAS).
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