MAXI: Monitor of All-Sky X-ray Image

Monitor of All-sky X-ray Image (MAXI) is the X-ray all-sky monitor on the International Space Station (ISS). It has been continuously scanning almost the entire sky in every ISS orbit (92 minutes) since August, 2009. MAXI has two instruments; Gas Slit Camera (GSC) and Solid-state Slit Camera (SSC). Both utilize slit-camera optics. For the one-dimensional position sensitive X-ray detector, GSC uses gas proportional counters while SSC uses CCDs. The 3-σ detection limit in 3-10 keV for one GSC scan and for one day are 60-100 mCrab and 12–15 mCrab, respectively. The MAXI/GSC Nova-Alert System is used for the automated nova search. MAXI detected X-ray time variabilities from a variety of objects from flaring stars to extragalactic objects. As of September, 2022, MAXI has discovered 31 new X-ray objects including 14 black-hole binaries, 13 neutron-star binaries, and one white-dwarf binary. The 7-year GSC catalog (3MAXI), 4-year SSC catalog (1MAXIS) and CCD diffuse X-ray map were compiled.