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TITLE:   GCN CIRCULAR
NUMBER:  29101
SUBJECT: GRB 201221B: Fermi GBM Final Real-time Localization
DATE:    20/12/21 14:23:08 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely SHORT GRB

At 14:11:43 UT on 21 Dec 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 201221B (trigger 630252708.014426 / 201221591).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 110.6, Dec = 32.0 (J2000 degrees, equivalent to J2000 07h 22m, 32d 00'), with a statistical uncertainty of 4.1 degrees.

The angle from the Fermi LAT boresight is 14.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201221591/quicklook/glg_skymap_all_bn201221591.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201221591/quicklook/glg_healpix_all_bn201221591.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201221591/quicklook/glg_lc_medres34_bn201221591.gif

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TITLE:   GCN CIRCULAR
NUMBER:  29147
SUBJECT: GRB 201221B: Insight-HXMT/HE detection
DATE:    20/12/23 11:32:53 GMT
FROM:    Ce Cai at IHEP  <caice@ihep.ac.cn>

C. Cai, S. Xiao, Y. F. Du, Y. G. Zheng, Q. Luo, Q. B. Yi, 
Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, 
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team:

At 2020-12-21T14:11:43.00 (T0), Insight-HXMT/HE detected 
GRB 201221B (trigger ID: HEB201221591) in a routine search of the data, 
which also triggered Fermi/GBM (GCN #29101).

The Insight-HXMT/HE light curve mainly consists of a single 
pulse with a duration (T90) of 0.03 s measured from T0-0.00 s. 
The 1-ms peak rate, measured from T0-0.005 s, is 9739 cnts/sec. 
The total counts from this burst is 193 counts. 
URL_LC: http://twiki.ihep.ac.cn/pub/HXMT/GRBList/HEB201221591_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (deposited energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 
 
Insight-HXMT is the first Chinese space X-ray telescope, which was 
funded jointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information about it could be found at: 
http://www.hxmt.org.