Monitor of All-sky X-ray Image (MAXI) Mission on the International Space Station

Abstract

The Monitor of All-sky X-ray Image (MAXI) is an X-ray all-sky monitor that will be attached to the Japanese Experiment Module (Kibo) of the International Space Station (ISS). MAXI will be transported by an H-II Transfer Vehicle (HTV) or the space shuttle in 2008. It employs X-ray slit cameras composed of slat collimators and a one-dimensional position-sensitive detector, with a field of view (FOV) of 1° x 160°. This narrow FOV sweeps almost the entire sky due to the orbital motion of the ISS without any pointing mechanism. The latitude of the source from the orbital plane is determined by a one-dimensional position-sensitive X-ray detector. The spatial resolution is 1.5 degrees in full width at half maximum (FWHM). MAXI employs two types of X-ray detectors, the CCD detector and the gas proportional counter. The CCD covers 0.5 to 12 keV with a moderate energy resolution of ＜ 150 eV in FWHM at 5.9 keV, and the gas counter covers 2 to 30 keV with an effective area of 5350 cm2. This large area provides unprecedented sensitivity as an all-sky monitor, and enables us to systematically monitor faint sources such as extra-galactic objects for the first time. The data transferred to the ground station will be analyzed automatically to detect transient sources, such as X-ray novae. Observers will be informed of the position and flux of the sources as soon as possible via the Internet. All observed data will also be made public in an appropriate data format.