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The Suzaku Images of the Galactic Center X-ray Emission (GCXE). Spatial distribution of the GCXE and stars ( Uchiyama+11). Average spectrum of the GCXE (Uchiyama+13). Strong Fe XXV Kα , S XV Kα , and Fe I Kα the GCXE consists of
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The Suzaku Images of the Galactic Center X-ray Emission (GCXE) Spatial distribution of the GCXE and stars (Uchiyama+11) Average spectrum of the GCXE (Uchiyama+13) • Strong Fe XXV Kα, S XV Kα, and Fe I Kα the GCXE consists of • High Temperature Plasma (HP), Low Temperature Plasma (LP), and • Cold Gas . • The GCXE is not integral emission of unresolved X-ray stars. X-ray surface brightness of Fe XXV Kα Fe XXV Kα Fe I Kα factor 3-4 of discrepancy S XV Kα
Variable XRN Sgr B2 (Nobukawa+11) 1 X-ray Reflection Nebula (XRN): Echo of Past Sgr A* Flares Line of sight Positions of XRNe (Ryu+13) 700 yr activity history of Sgr A* (Ryu+13) • Suzaku and other satellites found time variability • of Fe I Kα and hard X-ray from molecular clouds • (MCs, e.g. Muno+07, Inui+09, Ponti+10). • X-ray light echoes of past flares of super massive black hole Sgr A* at the center of our Galaxy. • Key information for activity history of Sgr A*. Accurate past light curve of Sgr A* (in time and fluxes) depends on 3-d distribution of the MCs (e.g. Ryu+13).
2-2 Hint of a RP from a Close Vicinity of Sgr A* Suzaku spectrum near Sgr A* (l = 0°.1, b = -0°.1) If Sgr A* was very active about a few 105 years ago as is suggested by the GC south plasma, it might also leave a RP at a close vicinity of Sgr A*. Suzaku found a hint of RP near Sgr A* (l = 0°.1, b = -0°.1 ). The plasma also shows a hint of Compton shoulder of the 6.4 keV line. • The fitting of a CIE plasma model leaves residuals at ~ 6.7 keV and ~ 6.3 keV. • RP model and Compton shoulder of the 6.4 keV line significantly improve the fitting.
o.2 0.1 0.0 -0.1 -0.2 (deg) New Sciences of the GCXE to be unveiled by ASTRO-H Galactic longitude Proposed 3 positions overlaid on Suzaku XIS images Fe XXV Kα line image Fe I Kα line image (3) GC West (3) GC West (1) Sgr A* (1) Sgr A* (2) GC East (2) GC East HXI FOV SXS FOV 10 pc o.2 0.1 0.0 -0.1 -0.2 (deg) Galactic longitude We propose three pointing observations, which play complementary roles. (1) The Sgr A* region is for the study of Sgr A* and its vicinity. (2) The GC East region is the strongest in Fe I Kα (XRN) (“MC1” in Ponti+10). (3)The GC West is the region of pure HP and LP components with no bright XRN.
Suzakuspectrum shows a hint of the Compton shoulder of Fe I Kα. We can obtain pure Fe I Kα spectrum by subtracting (3) GCWestdata from (2) GC East data. The shape of the Compton shoulder gives 3-D position of the MC.Then we can obtain more accurate light curve of Sgr A*. SXS simulation spectrum of (2) – (3) 1. Accurate History of Past Sgr A* Flares Fe I Kα Fe I Kβ Compton shoulder of Fe I Kα In a photo-ionized plasma formed by a past Sgr A* flare, the temperature ratio of ionization (kTz) to electron (kTe) should be higher near Sgr A*. We can see the difference of kTz/kTe between (1) Sgr A* and(3) GC Westregions. 2. Plasma Diagnostic for Sgr A* Activities SXS simulation spectrum of (1)vs.(3) Sgr A* region (kTz/kTe = 3.0) GC West (kTz/kTe = 1.5) Fe XXV Kα complex Fe XXVI Lyα
SXS & HXI wide-band simulation spectrum from (1) 3. Non Thermal Emission and a Coming Sgr A* Flare • High-quality spectra of the GCXE with SXS/SXI/HXI give us the first opportunity to investigate • exact nature of hard X-ray (possibly non-thermal) emission with no energy gap between 0.5 and 50 keV. • coming flare of the nearest massive black hole Sgr A* (Gillesen et al. 2012). 4. Dynamics of the GCXE Plasma and XRNe SXS simulation spectrum of (1),(2),and (3) Fe XXVI Lyα1 & Lyα2 50 km/s blue shift (2) 100 km/s red shift 200 km/s broadening (1) (3) Doppler shift of the GCXE lines tell the dynamics of the GC plasma and XRNe. Do they show the same Galactic rotation curves as stars ?
5. The GC: a Treasure Box in Astrophysics We have made many “unexpected” discoveries from the GC with Ginga, ASCA, and Suzaku, such as the GCXE, XRNe, RP and etc. The high-quality spectra of ASTRO-H will surely provide new “unexpected” discoveries, because the GC is full of mystery and a treasure box in astrophysics.