1X-ay Study of
3-D View of the Galactic Center Region
and1000-yr Activity History of Sagittarius A*

Takeshi Go Tsuru (Kyoto University)
on behalf of the Suzaku GC team.
20130530_Vulcano2013_v9.key

Observation of the GC region with Suzaku

1deg

2

R: 0.5-2.0keV
G: 2.0-5.0keV
B: 5.0-8.0keV

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 Background204pointings, 5.96Msec
SWG, AO, LP, KP x2 (|l|<3.5°, |b|<5°)

36 refereed papers,
7 Doctor Theses.

30.1

He-like S Kα
(2.45-keV line)

Neutral Fe Kα(6.4-keV line)

1deg

Narrow Line

0.01

−1Counts s keV−1

1

Suzaku Spectrum of the GC region

Mapping

1He-like Fe Kα(6.7-keV line)

25Energy (keV)106.7-keV Line Image (He-like Fe Kα)4

6.7keV (Continuum subtracted)

CHAPTER 2. REVIEWSgr A*

Photons cm-2 s-1 arcmin-2

1010(a)-5•
6.7-keVFe XXV K-610-810-9•

GC10-7

GRr〜500ly-

F=10×exp(–l/0.6deg) + exp(–l/50deg)

0.01

0.1

1

10

S XV K(b)ThermalPlasmas
10-5
smoothly
distribute in-6
10
the GC region.
-7
10
The origin is still underdebate.
-8
10
Truly
diffuse plasma-910filling in the GC region.
Or, collectionof faint 1
0.01
0.1
*
unresolved
point
Distancefrom Sgr A along thsources.

Photons cm-2 s-1 arcmin-2

100ly

100

*

Distance from Sgralong
theSgrlongitudel* A(deg,fromA*) |l* | (degree)

Uchiyama+11, +12-

56.4-keV Line Image (Neutral Fe Kα)

FeI 6.4 keV Map by Suzaku- 0.0ºSgr B2
M0.74–0.09

Sgr B10.5º

1.0º

Sgr A*b

Sgr C0º-0.5º

Sgr A*

Sgr Cl-0.9º

CS ( J=1–0) Map by Tsuboi+1999

Sgr Bb300 pc of the Central Molecular Zonel• 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 ?

counts/sec/ke10 36X-ray Reflection Nebula

HAPTER 2. REVIEW10 42020.01

Sgr(a) B2
Sgr B2
Koyama+07

5(b) M359.47 0.15

• Equivalent Width : 1–2keV• K-edge : N = 2–10 x 10 cm
Time: region after subtra
ig. 2.20.—: X-ray spectra of giant
MCs Variablein the GC•
pectrum of Sgr B2 (Koyama et al., 2007b). (b) spectrum of M 359.43−0
counts/sec/keV

Fig. 5.

6.4-keV line

10−0.07 (a) an23H

3

10 4

Energy-2

Size ~10 lys, τ ~ 10 yrst al., 2009). TheDeep
spectralfeatures
suggest the X-ray origin (see text).
absorptionedge
46(keV)(a) Sgr B2=−

Fig. 5.
Inui+09, Nobukawa+11
1995

2000

Ionizing particle is X-ray“X-rayReflection Nebula(XRN)”
0~~
σ=±(b)Sgr A, G 0.1–0.1(c)2
Need a source.
± .
×39ergs/s
510with LX ~ 10
Energy (keV) = ==No such bright source.
−0.07 (a) andM 359.47−0.15(b).
Sgr A* is only
possiblesource.
. ± . one×2

2005 (year)•••−−−−2−−−~−−:ı:ıEcho of the past activity of Sgr A*J =l b =7Long Term Light Curve of Sgr A*dXRNisecho.

Collecting the data of XRNe
allows us to obtain past activityof Sgr A* reaching ~1000yr.

Face on(Top View)

Sgr A*Very Unique Study

Only Sgr A* allows us to access sucha long-term activity of a SMBH.

• L (Sgr A*) L (XRN) x Mass(XRN) x d^2 The line of sight• Distance “d” between XRN and Sgr A* position of XRN isX

X→ Look back time.

necessary.

8“X-ray Tomography”• The GC thermal plasma
distributes smoothly.

• If an XRN (MC) is located in thenear side of the thermal plasma,then soft X-rays from the plasma
is absorbed by the XRN due tophoto-absorption.

• In the case that the XRN (MC) islocated in the far side of thethermal plasma, soft X-rays fromthe plasma is un-absorbed.

Absorbed

XRN

GC –XRN

NearObserver

Thermal PlasmaMC) is located in the GC thermalplasma.

Thermal Plasma• An XRN (e.g. Molecular Cloud:FarCosmic X-ray Tomography

6.4-keV(XRN) XRN

Far100 ly

2.45-keV(Plasma)StronglyAbsorbed
100 ly100光年

Absorbed

Sgr A*XRN

GC –XRN
Sgr C

Thermal Plasma

6.7-keV(Plasma)

Thermal Plasma

Sgr B2100 ly

9

Sgr A*XRNNearA*
超巨大BH
Observer SgrQuantitative studies allow us to obtainthe line of sight potions of the XRNe.

LessAbsorbed

10Spectral Modeling
X-ray spectrum as a function of theline of sight position of XRN.

Cnt/s/keV

FeXXV
6.7 keV– 0.9
XRN

Plasma Emission→

Spectral ModelContinuum of0.1
Plasma Emission

FeI 6.4 keV

1.0 Far– 0.8– 0.7

XRN

– 0.6

RXRN

0.01

XRN

Decrease

13Energy (keV)

5Observer– 0.5 Center
– 0.4
– 0.3
– 0.2
– 0.1
0.0 Near
Ryu+09,	  +13

GC Plasma

Spectral Fitting

1-RXRN

Abs2

RISM

Abs1

Foreground-EV• Observer
Flux (E) = Abs1 × (GC-Plasma-E × R)
+ Abs1× Abs2 × (GC-Plasma-E × (1–R)+ XRNE )+ Foreground-E + CXB

11

123-D distribution of XRNe
Edge-­‐on	  view

Face-­‐on	  view

farnear
Ryu+0.9, +13

13Light curve of Sgr A* in the past
Ryu+0.9, +13

With 90% errors

time variability

LX

Sgr A* is very quiet at present.
← PastTime (year)

Current• Sgr A* had been in active phase 50 - 600 years ago.
• Sgr A* made nearly one order of magnitude variation in ashort time (<10 years) at a couple of times.

How about before 600 yrs ago ?

14No. 2, 1998
GALACTIC CENTER CO SURVE
Access the activityof 1500 yrsago

ASCA GIS : Center of Feline complex (6.4-6.9keV)

12CO (Oka+98)

Maeda89l = 3.2° “Clump 2”?
Sgr C
Sgr Bl = 3.5° exhibits
especially strong
6.4 keV line

• MC called “Clump 2” is located at theGalactic 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 theactivity of 1500 yrs ago (if it would bean XRN).

FIG. 2.ÈMaps of the 12CO J \ 1È0 and 13CO J \ 1È0 line emission integrated over the veloc
drawn at every 200 K km s~1 for 12CO and at every 100 K km s~1 for 13CO. Mapping areas are indbeams).

making Suzaku observation now.

S2

A “cloud” falling into Sgr A*

15

ėDeclination (arcsec)

d0.2
0.1

2011.3

Sgr A*S2m2008.3

2004.5(0lĂ

0.1

[W

0.2
0.3

0.2

0.1



0m

Right ascension (arcsec)

Gillessen+2012

A cloud is approaching Sgr A* and will pass at ~3100 times theevent horizon of Sgr A* in the summer of this year (2013).
Sgr A* will be active. Activity lasts in the next 30 years.

NMSummary• Developed “X-ray Tomography”.
• Obtained 3-D position of each XRN 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 (LX ~1039ergs/s)
continuously in the past 600 yrs.

•Sgr A* became quiet (LX ~1033 ergs/s) in the last 100 yrs.

16