[vsnet-grb-info 28242] GRB 210627B: GECAM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30345
SUBJECT: GRB 210627B: GECAM detection
DATE:    21/06/30 04:07:22 GMT
FROM:    Wangchen Xue at IHEP  <xuewc at ihep.ac.cn>

W. C. Xue, S. L. Xiong, X. Y. Song, Y. Huang, S. L. Xie, S. Xiao, C. Cai,
J. C. Liu, C. Y. Li, Y. Q. Zhang,  Y. Zhao, Z. W. Guo, X. Y. Zhao, C. Zheng,
Z. H. An, C. Chen, G. Chen, W. Chen, M. Gao, K. Gong, D. Y. Guo, J. J. He,
B. Li, C. Li, J. H. Li, Q. X. Li, X. B. Li, X. Q. Li, Y. G. Li, X. H. Liang,
J. Y. Liao, J. C. Liu, X. J. Liu, Y. Q. Liu, F. J. Lu, Q. Luo, X. Ma,
G. Ou, W. X. Peng, R. Qiao, D. L. Shi, J. Y. Shi, L. M. Song,
G. X. Sun, X. L. Sun, Y. L. Tuo, C. W. Wang, J. Z. Wang,
P. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, S. Yang, M. Yao, Q. B. Yi,
B. X. Zhang, C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang, H. M. Zhang,
K. Zhang, P. Zhang, S. N. Zhang, Z. Zhang, S. Y. Zhao, S. J. Zheng,
X. Zhou (IHEP), report on behalf of GECAM team:

During the commissioning phase, GECAM-B was triggered in-flight by a long
burst, GRB 210627B, at 2021-06-27T17:57:21.550 UTC (denoted as T0), which was
also observed by Fermi/GBM (GCN #30332).

According to the GECAM-B light curves in about 20-500 keV, 
this burst mainly consists of multiple pulses with a duration of 14.33 s.

The GECAM light curve could be found here:
http://twiki.ihep.ac.cn/pub/GECAM/GRBList/multiLCvsE_tn210627_175830.png

GECAM-B localized this burst to the following position (J2000):
Ra: 240.1 deg
Dec: 2.0 deg
Err: 5.3 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. This position is 
consistent with the Fermi GBM localization (GCN #30332 and #30333) within
the error.

The location map could be found here:
http://twiki.ihep.ac.cn/pub/GECAM/GRBList/tn210627_175830_locationSatB_map.png

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).