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GCN Circular 30140

GECAM Sub-Threshold Detection of new magnetar Swift SGR J1555.2-5402
2021-06-07T08:25:44Z (3 years ago)
Ce Cai at IHEP <>
C. Cai, S. L. Xiong, Y. Huang, S. L. Xie, S. Xiao, Y. Zhao, J. C. Liu,
C. Y. Li, Y. Q. Zhang, W. C. Xue, C. Zheng, Z. W. Guo, X. Y. Zhao,
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,
X. Y. 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:

Regarding the new magnetar SGR J1555.2-5402 discovered by Swift/BAT 
(GCN #30120), there was no GECAM in-flight trigger or on-ground automated 
blind search trigger around the BAT trigger time (2021-06-03T09:45:46). 
Thus, we implemented a targeted search for sub-threshold burst signals 
from +/-35 s around BAT trigger time, using an improved coherent search 
algorithm (C. Cai, In preparation, L. Blackburn et al.). 

From the targeted search, we found a short soft burst at 
2021-06-03T09:45:46.670, with the most significant timescale of 10 ms. 
Its location is consistent with the Swift/BAT position (GCN #30120) and 
the spectrum is soft (Band function with Epeak = 70 keV, alpha = -1.9, 
beta = -3.7). We conclude this bursts is from SGR J1555.2-5402.

The GECAM light curve could be found here:

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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