TITLE:   GCN CIRCULAR
NUMBER:  31397
SUBJECT: GECAM observation of a burst from SGR J1555.2-5402
DATE:    22/01/07 09:32:07 GMT
FROM:    Y Q Zhang at IHEP  <yqzhang@ihep.ac.cn>

Y. Q. Zhang, S. Xiao, S. L. Xiong, C. Cai, P. Zhang, 
C. Y. Li, S. L. Xie, X. Y. Zhao, Y. Huang, X. Y. Song,
J. C. Liu,  Y. Zhao, Z. W. Guo, C. Zheng, W. C. Xue, C. W. Wang, 
Q. B. Yi, B. X. Zhang,  W. X. Peng, R. Qiao, D. Y. Guo, X. B. Li, 
X. Ma, L. M. Song, 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, 
H. M. Zhang, Z. H. An, M. Gao, K. Gong, B. Li, C. Li, J. H. Li, 
X. Q. Li, Y. G. Li, X. H. Liang, X. J. Liu, Y. Q. Liu, X. L. Sun, 
Y. L. Tuo, J. Z. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, S. Yang, 
C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang,
X. Zhou, 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 bright short burst from SGR J1555.2-5402 at 2022-01-06T13:33:47.500 UTC (T0).

According to the GECAM-B light curves in about 15-65 keV, this burst mainly
consists of a single pulse with a duration about 100 ms.

The GECAM light curve could be found here: 
http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_lc_grd_all_combine_95175227.png

GECAM-B localized this burst to the following position (J2000): 
Ra: 261.9 deg 
Dec: -46.7 deg
Err: 13.4 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 location given by 
GECAM-B alone is consistent with SGR J1555.2-5402 within the error.

In addition, according to our multiple-mission joint analysis system
(ETJASMIN, S. Xiao et al., submitted to MNRAS, S. Xiao et al., 2021, ApJ, 920 43) 
using GECAM-B and Fermi/GBM public data, this burst is localized to an annulus which is 
very consistent with SGR J1555.2-5402. 

The GECAM-GBM joint location could be found here:
http://twiki.ihep.ac.cn/pub/GECAM/GRBList/SGR20220106T133347.500-JointLoc.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).