X-ray observations of accretion disks

Abstract Present understandings of accretion disks based on X-ray observations are reviewed. The main focus is observational properties around black holes in binaries and their phenomenological interpretations. Since there several excellent reviews hole already, we here pick up a limited number important works which introduced key clues widen and/or deepen the understanding disks, recalling histories binary sources with astronomy satellites successively launched from United States, European countries, Japan. We at certain points compare some evidence similar phenomena observed weakly magnetized neutron star, to clarify basic nature disks. also try understand environments active galactic nuclei by applying what have learned them.