X-ay Study of 3-D View of the Galactic Center Region and 1000-yr Activity History of Sagittarius A*

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1 1 X-ay Study of 3-D View of the Galactic Center Region and 1000-yr Activity History of Sagittarius A* Takeshi Go Tsuru (Kyoto University) on behalf of the Suzaku GC team _GC2013_v1.key

2 Observation of the GC region with Suzaku 2 1deg R: keV G: keV B: keV Suzaku is the best observatory to observe diffuse emission from the Galactic center region. High Spectral Resolution, Large Collecting Area, Low and Stable Non-X-ray Background 204pointings, 5.96Msec SWG, AO, LP, KP x2 ( l <3.5, b <5 ) 36 refereed papers, 7 Doctor Theses.

3 Suzaku Spectrum of the GC region 3 Counts s 1 kev deg Narrow Line Mapping He-like S Kα (2.45-keV line) Neutral Fe Kα (6.4-keV line) He-like Fe Kα (6.7-keV line) Energy (kev) 10

4 6.7-keV Line Image (He-like Fe Kα) 4 6.7keV (Continuum subtracted) Photons cm -2 s -1 arcmin ly r 500ly GC F=10 exp( l/0.6deg) + exp( l/50deg) GR Sgr A* 6.7-keV Distance from Sgr A * along the longitude (degree) l* (deg, from Sgr A*) Uchiyama+11, +12 Thermal Plasmas smoothly distribute in the GC region. The origin is still under debate. - Truly diffuse plasma filling in the GC region. - Or, collection of faint unresolved point sources.

5 6.4-keV Line Image (Neutral Fe Kα) FeI 6.4 kev Map by Suzaku 5-0.0º M Sgr B2 Sgr B1 Sgr A* Sgr C b 1.0º 0.5º 0º -0.5º -0.9º CS ( J=1 0) Map by Tsuboi+1999 l Sgr B Sgr A* Sgr C 300 pc of the Central Molecular Zone l b 6.4-keV line generally traces the distribution of the molecular clouds. 6.4-keV fluorescence line is emitted from MC. What is the ionizing particles? Electrons or X-rays?

6 X-ray Reflection Nebula 6 Sgr (a) B2 Sgr B2 Koyama+07 Equivalent Width : 1 2keV 6.4-keV line K-edge : N H = 2 10 x cm -2 Time Variable : Size ~10 lys, τ ~ 10 yrs (a) Sgr B2 Deep absorption edge 4 6 (kev) Inui+09, Nobukawa (year) Ionizing particle is X-ray X-ray Reflection Nebula () Need a source with LX ~ ergs/s No such bright source. Sgr A* is only one possible source. Echo of the past activity of Sgr A*

7 Long Term Light Curve of Sgr A* 7 d is echo. Collecting the data of e allows us to obtain past activity of Sgr A* reaching ~1000yr. Very Unique Study Face on (Top View) Sgr A* Only Sgr A* allows us to access such a long-term activity of a SMBH. L X(Sgr A*) LX() x Mass() x d^2 Distance d between and Sgr A* Look back time. The line of sight position of is necessary.

8 X-ray Tomography 8 The GC thermal plasma distributes smoothly. Far An (e.g. Molecular Cloud: MC) is located in the GC thermal plasma. If an (MC) is located in the near side of the thermal plasma, then soft X-rays from the plasma is absorbed by the due to photo-absorption. In the case that the (MC) is located in the far side of the thermal plasma, soft X-rays from the plasma is un-absorbed. Thermal Plasma Absorbed GC Near Observer Thermal Plasma

9 6.4-keV () Cosmic X-ray Tomography 100 ly 2.45-keV (Plasma) 100 ly 100光年 Absorbed Sgr A* GC Sgr C Thermal Plasma 6.7-keV (Plasma) Far Thermal Plasma Sgr B2 100 ly Strongly Absorbed 9 Sgr A* Near A* 超巨大BH Observer Sgr Quantitative studies allow us to obtain the line of sight postions of the e. Less Absorbed

10 Spectral Modeling X-ray spectrum as a function of the line of sight position of. Spectral Model Continuum of Plasma Emission Fe I 6.4 kev Fe XXV 6.7 kev Plasma Emission R 1.0 Far Center Decrease Energy (kev) Observer Near Ryu+09, +13

11 Spectral Fitting 11 GC Plasma 1-R R ISM Foreground-E V Observer Abs2 Abs1 Flux (E) = Abs1 (GC-Plasma-E R) + Abs1 Abs2 (GC-Plasma-E (1 R)+ E ) + Foreground-E + CXB

12 3-D distribution of e 12 Edge- on view Face- on view far near Ryu+0.9, +13

13 Radio Central Molecular Zone Line of Sight Position Y (ly) with Tomography v.s. MC with Radio Kinematics 13 (Binney+91, Sofue+95) (a) Face-on View far X2 Orb Assuming the kinematics model, with the observed line of sight of speed of MCs, the structures of - X1 elliptical orbit - Arm I & II are obtained. Y (ly) Y (ly) near D B2 X1 major axis Arm II B1 M 0.74 Sgr A* ~15º C3 Arm I To Sun X (ly) C2 C1 Galactic longitude X (ly) E X1 Orb NH N ( cm 2 ) The X-ray and radio result are consistent with the each other. Note that X-ray result is obtained without radio information.

14 Light curve of Sgr A* in the past 14 Ryu+0.9, +13 time variability With 90% errors L X Past Sgr A* is very quiet at present. Time (year) Current Sgr A* had been in active phase from 50 to 600 years ago with ~10^39ergs/s. Sgr A* made nearly one order of magnitude variation in a short time (<10 years) at a couple of times. How about before 600 yrs ago?

15 Access the activity of 1500 yrs ago 15 ASCA GIS : Center of Fe line complex ( keV) 12CO (Oka+98) Maeda89 l = 3.2 Clump 2 Sgr C Sgr B l = 3.5 exhibits especially strong 6.4 kev line MC called Clump 2 is located at the Galactic longitude of 3.2 deg. The ASCA data suggest strong 6.4keV line, which would be due to Clump 2. We would be able to access the activity of 1500 yrs ago (if it would be an ). making Suzaku observation now.

16 S2 A cloud falling into Sgr A* 16 d 0.2 Declination (arcsec) S2 Sgr A* Right ascension (arcsec) Gillessen+2012 A cloud is passing at ~3100 times the event horizon of Sgr A*.

17 Summary 17 Developed X-ray Tomography. Obtained 3-D position of each with it. Obtained the X-ray light curve of Sgr A* in the past 600 yrs for the first time. Sgr A*has made a number of flares (L X ~10 39 ergs/s) continuously in the past 600 yrs. Sgr A* became quiet (L X ~10 33 ergs/s) in the last 100 yrs.

18 Thank you.