Investigating gamma-ray bursts by joining Insight-HXMT and other gamma-ray spacecraft

The Chinese mission Insight–HXMT allows for a high sensitivity study of the X–ray sky in 1250 keV, thanks to a smart combination of collimated detectors operating in different energy bands and providing a source location accuracy of 1 arcmin for a 20-σ source. In addition to observing Galactic sources, the HXMT High Energy (HE) instrument also operates in the so-called GRB mode, that makes it possible to detect and characterise GRB prompt emission from 200 keV to 3 MeV with an effective area as high as 2000 cm2 , thus filling the sensitivity gap of presently flying main GRB detectors in this energy range. We report the results of intensive simulations of the expected performances of HXMT for GRB science, showing how, especially in combination with, e.g., Swift/BAT and Fermi/GBM, the HXMT/HE will provide a significant improvement in the characterisation of temporal and spectral properties of the prompt emission of long GRBs, as well as an improved detection rate and better spectral characterisation of short GRBs.