The MAXI Mission on the ISS: Science and Instruments for Monitoring All-Sky X-Ray Images

Abstract

The Monitor of All-sky X-ray Image (MAXI) mission is the first astronomical payload to be installed on the Japanese Experiment Module — Exposed Facility (JEM-EF or Kibo-EF) on the International Space Station. It has two types of X-ray slit cameras with wide FOVs and two kinds of X-ray detectors consisting of gas proportional counters covering the energy range of 2 to 30 keV and X-ray CCDs covering the energy range of 0.5 to 12 keV. MAXI will be more powerful than any previous X-ray All Sky Monitor payloads, being able to monitor hundreds of Active Galactic Nuclei. A realistic simulation under optimal observation conditions suggests that MAXI will provide all-sky images of X-ray sources of $\sim $20 mCrab ($\sim $7 $\times$ 10$^{-10} $erg cm$^{-2} $s$^{-1}$ in the energy band of 2–30 keV) from observations during one ISS orbit (90 min), $\sim $4.5 mCrab for one day, and $\sim $2 mCrab for one week. The final detectability of MAXI could be $\sim $0.2 mCrab for two years, which is comparable to the source confusion limit of the MAXI field of view (FOV). The MAXI objectives are: (1) to alert the community to X-ray novae and transient X-ray sources, (2) to monitor long-term variabilities of X-ray sources, (3) to stimulate multi-wavelength observations of variable objects, (4) to create unbiased X-ray source cataloges, and (5) to observe diffuse cosmic X-ray emissions, especially with better energy resolution for soft X-rays down to 0.5 keV.

Methods and results of a search for gravitational waves associated with gamma-ray bursts using the GEO 600, LIGO, and Virgo detectors

“…The GRB events were obtained from the gamma-ray burst coordinates network (GCN) [77], supplemented by the Swift and Fermi on-line catalogues, 4 as well as the published Fermi four-year catalogue [78]. Most of the GRBs in our sample were detected by Swift and Fermi; a few of the GRBs were detected by other space borne experiments such as INTEGRAL [79], AGILE [80], or MAXI [81].…”

Determination of parameters of Long-Term variability of the X-ray pulsar LMC X-4

“…To check whether the solution for the precessional modulation obtained in the 15-50 keV X-ray band was applicable to the measurements in the soft X-ray band (2-20 keV), we used data from the Japanese MAXI all-sky monitor (Matsuoka et al 2009) installed on the Japanese experimental module of the International Space Station. The monitor has been observing LMC X-4 since August 2009 and, thus, allows an independent time series of data completely overlapping in time with the BAT/Swift data to be obtained.…”

Latest Results of the Maxi Mission

“…Moreover, Aql X-1 and 4U 1608-52 have a third, very dim state. We interpret it as the propeller effect in the unified picture of LMXB by Matsuoka et al (2009). Cir X-1 is a peculiar source, in the sense that the long-term behavior is not like typical LMXBs.…”

“…MAXI is the fist astronomical mission on the ISS, and started observation in August 2009 (Matsuoka et al, 2009). MAXI is attached to the exposed facility of the Japanese experiment module.…”