The scientific results from the X-ray observatory Hitomi

Abstract

Hitomi is the 6th Japanese X-ray astronomy satellite launched on 2016 Feb 17. Although it was unfortunately lost about 1 month from the launch, Hitomi produced many new scientific results, owing to extremely high spectral resolution of the non-dispersive SXS detector (X-ray microcalorimeter). From the observations of the Perseus cluster, a stringent upper limit of the turbulent pressure, only <7% of that of the thermal pressure, is obtained, and the metal abundance in ICM is found consistent to that of the solar vicinity. Power of the high resolution spectroscopy even with small photon counts is demonstrated in N132D and IGR J16318-4848. Emission/absorption line search was performed in Crab and G21.5−0.9. A result is obtained to support that the Crab nebula was born from an electron-capture supernova. New absorption line structures are detected from G21.5−0.9, although they need further confirmation because of low statistical significance of 3-4σ. To fulfill the calorimeter science, the XRISM project has been ongoing. Following XRISM, we have started preparing the next generation hard X-ray mission FORCE that is a successor of the hard X-ray imager onboard Hitomi, but with much better spatial resolution of 15 arcsec in HPD. They are planned to be launched by the end of March 2022 and late 2020's, respectively.