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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 - PowerPoint PPT Presentation
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Fe XXV Kα Fe I Kα
S XV Kα
•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
factor 3-4 of discrepancy
Average spectrum of the GCXE (Uchiyama+13)
Spatial distribution of the GCXE and stars (Uchiyama+11)
The Suzaku Images of the Galactic Center X-ray Emission (GCXE)
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).
1 X-ray Reflection Nebula (XRN): Echo of Past Sgr A* Flares
Line of sight Positions of XRNe (Ryu+13)
Variable XRN Sgr B2 (Nobukawa+11)
700 yr activity history of Sgr A* (Ryu+13)
2-2 Hint of a RP from a Close Vicinity of Sgr A*
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.
Suzaku spectrum near Sgr A* (l = 0°.1, b = -0°.1)
New Sciences of the GCXE to be unveiled by ASTRO-H
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.
Galactic longitude
Fe XXV Kα line image Fe I Kα line image
(2) GC East
(3) GC West
SXS FOVHXI FOV 10 pc
(1) Sgr A* (2) GC East
(3) GC West
(1) Sgr A*
Proposed 3 positions overlaid on Suzaku XIS images
o.2 0.1 0.0 -0.1 -0.2 (deg)
o.2 0.1 0.0 -0.1 -0.2 (deg) Galactic longitude
1. Accurate History of Past Sgr A* FlaresSXS simulation spectrum of (2) – (3)
Compton shoulder of Fe I Kα
Fe I KαFe I Kβ
SXS simulation spectrum of (1) vs.(3)
Fe XXV Kαcomplex
Fe XXVI Lyα
Suzaku spectrum shows a hint of the
Compton shoulder of Fe I Kα.
We can obtain pure Fe I Kα spectrum by subtracting (3)
GC West data 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*.
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 West regions.
2. Plasma Diagnostic for Sgr A* Activities
Sgr A* region (kTz/kTe = 3.0) GC West (kTz/kTe = 1.5)
CIE RP
kTz/KTe=1.0 1.5 3.0
G ratio
(x+y+z)/w0.70±0.04 0.88±0.0
41.84±0.0
7
3. Non Thermal Emission and a Coming Sgr A* Flare
Fe XXVI Lyα1 & Lyα2
100 km/s red shift
50 km/s blue shift
200 km/s broadening
SXS simulation spectrum of (1), (2), and (3)
SXS & HXI wide-band simulation spectrum from (1)
(1)
(3) (2)
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).
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 ?
4. Dynamics of the GCXE Plasma and XRNe
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.