§1. Introduction of MAXI

1. an X-ray source slit Solid-state Slit Camera (GSC) Gas Slit Camera (GSC) collimator position sensitive detector Forward FoV Zenithal FoV MAXI Earth Scanning direction Celestial sphere GSC SSC Detector Energy Effective Area Field of View Energy Resolution Position Accuracy Proportional counter (Xe + CO2 gas) 2 – 30 keV 5350 cm2 1.5 x 160 degree 18 % at (Mo-Ka) 0.1 degree X-ray CCD 0.5 – 10 keV 200 cm2 1.5 x 90 degree 140 eV 0.1 degree Chandra, Newton, Suzaku etc : low monitoring efficiency All Sky Monitors (RXTE ASM etc.) : low detection sensitivity ( ) P : period, r : separation between two black holes, G : gravitational constant M : mass of primary black hole, m : mass of secondary black hole, M◎ : solar mass Kepler’s 3rd law. OJ287 : 11.65 yr (Sillnapaa et al 1988) AO 0235+16 : 5.7 yr (Raiteri et al. 2001) Mrk501 : 23.6 day (Osone et al 2001) P = 2pr2/3G-1/2 (M+m)-1/2 = 1.7 yr(r / 1016 cm)2/3 (M / 108M◎)-1/2 (1+m/M)-1/2 Exploring an evidence of supermassive black hole binaries in AGN with MAXINaoki Isobe (RIKEN, isobe@crab.riken.jp ) and the MAXI Team §1. Introduction of MAXI • Instrument on MAXI MAXI carries two kinds of X-ray instruments, Gas Slit Camera (GSC) and Solid-state Slit Camera (SSC). • Monitor of All Sky X-ray Image (MAXI) • X-ray observatory, to be mounted on the Japanese Experimental Module (JEM) of the International Space Station (ISS). • MAXI scans all over the sky in every 90 minutes. • Operation start : 2008. • Mission life time : 2 years (minimum). • Sensitivity : 10 mCrab in one orbit, 1 m Crab in a week significantly higher than those of previous X-ray monitors (such as RXTE ASM). • Everyone will be able to access the data (lightcurves, images, and spectra) with MAXI, through the internet. The concept of GSC and SSC. GSC and SSC consist of a narrow slit, slat collimators and position sensitive detectors. Both instruments have two field of views, toward horizontal and zenithal directions. Simulated all sky X-ray image, in 5 month observation with MAXI GSC SSC Slit and collimator Galactic plane JEM A4-size window Proportional counter A schematic view of ISS The structure of MAXI CCD Chip • What to be explored with MAXI • Continuous monitoring of variable X-ray sources, such as black holes, and especially, active galactic nuclei (AGNs) • Prompt alert of transient X-ray sources, such as X-ray burst, flaring stars, and supernovae. • Mapping the distribution of distant AGNs by probing the cosmic X-ray background. • Mapping the distribution of hot plasma (and elements such as Si, S and Fe) in the Galactic plane. • etc. §2. Periodicity in AGN - as an evidence of super massive black hole binaries in AGN- • Periodic variation has been discovered in a few AGNs, in optical, radio or X-ray observations. • Such periodicity is frequently interpreted on the basis of Keplerian motion of supermassive black hole binary in AGNs (and associated helical motion of jets). (e.g. Sillnapaa et 1988, Sudou et al. 2003 ). • Search for X-ray flux periodicity with MAXI • X-ray observation of AGNs is important to probe into the central regions close to the black hole, such as accretion disk. • However, previous X-ray observatories are not adequate to systematic search for X-ray periodicity. • MAXI can measure X-ray flux of more than 100 AGNs, weekly or even daily, thanks to its unprecedentedly high sensitivity. Examples MAXI is the first ideal observatory to systematically search for X-ray flux periodicity of AGNs, as an evidence of supermassive binary black hole. ＊ : Galactic sources ＋ : AGNs ○ : Clusters of Galaxies Periodic elliptical motion of a radio core in 3C66B (Sudou et al. 2003) Sensitivity of RXTE ASM M～ 4.4x109M◎ , r～ 5.5 x 1016 cm Sensitivity of MAXI (1 week) Historical light curve of a famous BL Lac object OJ 287 in optical V band (Valtaoja et al. 2000). 11.65 yr X-ray flux of famous X-ray sources, plotted against the distance to them. Simulated lightcurve of an X-ray source, with a flux of about 1 mCrab. Although periodicity is not introduced in the simulation, MAXI can explore periodicity in these sources. (1 mCrab = 2.4 x 10-8 erg s-1 cm-2 in 2 – 10 keV) Sources, from which periodicity is indicated in other wavelength. Almost all of these source is detected with MAXI. M～ 5 x109M◎ , r～ 3 x 1017 cm