Balloon-borne hard X-ray imaging observations of non-thermal phenomena

Non-thermal phenomena is now-a-days recognized as an important half of the energetics of the Universe. Hard X-ray emission from energetic particles is the most important clue to investigate the non-thermal phenomena. Hard X-ray imaging telescopes are known to improve the sensitivity of hard X-ray observations dramatically. Since hard X-rays above 25 keV can be observed at the altitude of 40 km, we are performing hard X-ray imaging balloon experiments as the path finders Of future satellite missions of hard X-ray imaging. Major fields we are looking into are non-thermal components from SNR and Cluster of galaxies and the power law components from AGN even with thick column. The former are related to acceleration mechanisms of high energy particles responsible for hard X-ray power law components. The latter is the complete search of emission from massive blackholes which contribute most to the cosmic X-ray background. Our current balloon programs are InFOC mu S experiment and SUMIT project. NeXT is the hard X-ray imaging mission proposed as the next Japanese X-ray mission.