IceCube-200926A: Upper limits from Insight-HXMT Observations

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.