TITLE:   GCN CIRCULAR
NUMBER:  28586
SUBJECT: IceCube-200926A: Upper limits from Insight-HXMT Observations 
DATE:    20/10/09 06:14:34 GMT
FROM:    Donglian Xu at Tsung-Dao Lee Institute  <donglianxu@sjtu.edu.cn>

Yu-Ling Chang (TDLI), Jinyuan Liao (IHEP), Chen Wang (NAOC), Yi Nang (IHEP), Na Sai (IHEP), Youli Tuo (IHEP), Ju Guan (IHEP), Chengkui Li (IHEP), Yuan Liu (NAOC), Jianyin Nie (IHEP), Donglian Xu (TDLI), Marcos Santander (U. Alabama), Wenlian Li (TDLI), Lian Tao (IHEP), Shijie Zheng (IHEP), Shaolin Xiong (IHEP), Shuangnan Zhang (IHEP), report on behalf of the TDLI and Insight-HXMT teams

Insight-HXMT observed the field of IceCube-200926A (GCN Circ. 28504) from 01:34:59 UTC September 29, 2020 to 10:49:34 UTC October 1, 2020 collecting a total of 8-epoch of data spanning ~2.5 days. The observations were done with small-sky scan mode with a scanning radius ~7 degrees and a total observation time of 20 ks.

We searched for emission from a new X-ray transient source. Preliminary analysis indicates no significant (> 5 sigma) new excess emission in all three bands, LE, ME, and HE of Insight-HXMT, at the IceCube-200926A best-fit position. 

Assuming an absorbed power-law spectrum (photon power-law index = 1.9 and nH column density = 3.14e21 fixed) for a point source at the position of this neutrino event, the 5-sigma flux upper-limits are reported below:

LE Band (1-6 keV):
6.2e-11 erg cm^-2 s^-1 

ME Band (7-40 keV):
2.5e-10 erg cm^-2 s^-1   

HE Band (25-100 keV):
1.1e-10 erg cm^-2 s^-1  


All measurements above are made with the NaI detectors operating in the
regular mode with the energy range of about 1-250 keV (record energy).

Insight-HXMT is the first Chinese space X-ray telescope, which was 
fundedjointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org.