1. X-ray Observations of the Dark Particle Accelerators
Hironori Matsumoto (Kyoto Univ.)

2. Outline TeV unID objects: “Dark particle accelerators”
The Suzaku satellite
Suzaku Observations
HESS J
HESS J
TeV J
HESS J
HESS J (SNR CTB37B)
HESS J 　(PWN)
Summary
(with ID objects)

3. TeV unidentified objects
TeV Galactic Plane Survey
(Aharonian et al. 2005, 2006)
HESS J
First example: TeVJ
discovered by HEGRA
(Aharonian et al. 2002)
HESS J
Many have been discovered in the Galactic Plane with H.E.S.S.
Gal. Cent.
Spatially extended
No counterpart.
HESS J
HESS J
Dark particle accelerators
HESS J

4. Implications What particles are accelerated, protons or electrons?
TeV gamma-rays  High-energy particles!
What particles are accelerated, protons or electrons?
If electrons,
X-ray … synchrotron
TeV … Inverse Compton of CMB
X-ray
TeV
E2f(E)
Electron origin
Synch IC
Flux(TeV)/F(X)
=U(CMB)/U(B)
~1 with a few micro Gauss
Energy
Electrons emit synchrotron X-rays very easily!
E2f(E) π0
Proton origin
Flux ratio (F(TeV)/F(X)) is a key to clarify the particles.
Energy

5. + The Suzaku Satellite Hard X-ray Detector (HXD) X-ray Telescope (XRT)
X-ray Imaging Spectrometer (XIS) +

6. Onboard Detectors
X-ray Telescope (XRT) + X-ray Imaging Spectrometer (XIS)
Mirror + CCD
E=0.3—12keV
Imaging & Spectroscopy
High sensitivity (low background) & High-energy resolution
Hard X-ray Detector (HXD)
Semiconductor (PIN-Si) & scintillator (BGO&GSO)
E=10—600keV
High sensitivity (low background), though no imaging capability.
Suzaku is the best tool for studying dim and diffuse objects.

7. GC spectrum XIS spectrum
Clear iron lines
6.4keV
6.7keV
6.9keV
XIS spectrum
High-energy resolution & High sensitivity (Low BGD)

8. HESSJ1614-518 Brightest among the new objects. XIS FOV 50ks HESSJ1614
HESS TeV γ-ray image (excess map)
Brightest among the new objects.
XIS FOV
50ks
HESSJ1614
(l, b)=(331.52, -0.58)

9. XIS FI (S0+S2+S3): 3-10keV band
XIS image　of HESS J1614
XIS FI (S0+S2+S3): 3-10keV band
Obs. 50ks
TeVγ-ray
Src A
Swift XRT also detected
(Landi et al. 2006)
Src B
Extended object

10. XIS spectra Featureless non-thermal Featureless, but extremely soft
Src A spectrum
HESS J1614
Src A
NH=1.2(±0.5)e22cm-2
Γ=1.7(±0.3）
F(2-10keV)=5e-13erg/s/cm2
Src B
Src B spectrum
Featureless
non-thermal
NH=1.2(±0.1)e22cm-2
Γ=3.6(±0.2）
F(2-10keV)=3e-13erg/s/cm2
Featureless,
but extremely soft

11. Plausible X-ray counterpart: src A
B=10μG
HESS J1614
Src A
Src B
B=1μG
src A
B=0.1μG
Src A
F(1-10TeV)/F(2-10keV)=34
Difficult to explain both the TeV gamma-ray and X-ray from the electron origin.
The origin of srcA is not clarified.
Matsumoto et al. 2008, PASJ, 60. S163 (Suzaku special issue No.2)

12. HESSJ1616-508 XIS FOV HESSJ1616 45ks (l, b)=(332.391, -0.138)
HESS TeV image (excess map)
(l, b)=( , )
XIS FOV
45ks
Provided by S. Funk (MPI)
HESSJ1616

13. XIS image of HESS J1616 F(TeV)/F(X)>55 45ks No X-ray counterpart
XIS FI (S0+S2+S3): 3—12keV
TeV image
F(TeV)/F(X)>55
45ks
No X-ray counterpart
F(2-10keV)<3.1e-13 erg/s/cm2

14. If we assume electrons…
Very weak B
(B<1μGauss)
realistic?
Suzaku upper limit or
Strong cut-off
HESSJ1616 SED
Matsumoto et al. 2007, PASJ, 59, 199　(Suzaku Special Issue No.1)

15. PWN of PSRJ1617-5055? INTEGRAL 18-60keV Landi et al. 2007
XMM-Newton keV
PSRJ1617
PSRJ1617
SNR RCW103
Neither radio (Kaspi et al. 1998) nor X-ray has detected the PWN.
Why is there no X-rays bridging the pulsar and HESSJ1616?
Landi et al. 2007

16. TeV J2032+4130 First TeV unID object (in 2002, HEGRA).
HEGRA TeV gamma-ray image
First TeV unID object (in 2002, HEGRA).
Cygnus region. Close to
Cyg OB2 (OB stars)
Cyg X-3 (micro-QSO)
EGRET source
Extended (~6arcmin)
No extended X-ray emission has been found before Suzaku.
Aharonian et al. (2005)

17. Suzaku observation of TeV J2032
December 2007, 40ks obs.
Two extended X-ray objects
src2
src1
TeV region
Murakami, H. et al., in preparation

18. X-ray spectrum of the sources
Murakami et al., in preparation
Both sources show power-law spectra.
src1
src2
Point sources
(Chandra)
Point sources
(Chandra) 1 2 5 10 1 2 5 10
Energy (keV)
Energy (keV) NH
(1022 cm-2) Γ FX
(10-13 erg s-1 cm-2)
Src 1
0.7
2.1
2.0
Src 2
0.5
1.8
F(TeV)/F(X; src1 or src2) = 10
proton acceleration in TeV J2032?

19. HESSJ1804-216 (l, b)=(8.401, -0.033) XIS FOV 40ks
HESS TeV γ-ray image (excess map)
Provided by S. Funk (MPI)
(l, b)=(8.401, )
XIS FOV
40ks
Softest TeV spectrum among
the new objects.
HESSJ1804

20. XIS image of HESS J1804 XIS FI (S0+S2+S3): 3-10keV src2 src1
Swift XRT (Landi et al. 2006)
Chandra (Kargaltsev et al. 2007)
TeV image
src2
src1
Src1: point src
Src2: extended
(Bamba et al. 2007)
Chandra (Kargaltsev et al. 2007)
40ks

21. XIS spectra src2 src2: extended src1 src1: point-like
HESSJ1804
src2
src2: extended
src1
src1
src2 Γ
-0.3±0.5
1.7±1.2 NH
(1022cm-2)
0.2(<2.2)
11±8
F(2-10keV)
10-13erg/s/cm2
2.5
4.3
src1: point-like
F(TeV)/F(X)
See Bamba et al. 2007, PASJ, 59,　S209 (Suzaku Special Issue No.1)

22. HESSJ1713-381 (CTB37B) HESSJ1713-381 coincides with the SNR CTB37B
Color: TeV
White: radio
SNR CTB37B
HESSJ coincides with the SNR CTB37B

23. Non-thermal hard X-ray
Suzaku keV
Nakamura, R. et al. PASJ, 2009, in print
reg1
reg2
Foreground src
Suzaku keV
Green: TeV (HESSJ1713)
Blue: radio
White: X-ray (Suzaku)
reg1
reg2
Reg1: coincides with the TeV peak
Reg2: offset hard emission

24. Diffuse thermal gas + point source
Suzaku keV
reg1
reg2
HESSJ1713
Diffuse thermal gas + point source
Thermal (kT=0.9keV)+PL(Γ=3.0)
PL: A point source discovered by Chandra (Aharonian et al. 2008).
Non-thermal X-ray Emission
Hard PL (Γ=1.5) (+ Leakage from reg1).
Roll-off (cut-off) energy > 15keV
 Very efficient acceleration.
F(TeV)/F(X)~0.2  B~8uG assuming IC.
Emax > 170 TeV

25. HESS J 1825-137 IC by high-energy electrons from the pulsar?
Spin-down luminosity
~ 2.8×1036 erg s-1
Characteristic age
21.4 kyr (Clifton 1992)
D~4kpc
30arcmin~30pc
@4kpc
HESS J
Aharonian et al. 2006
H.E.S.S TeV γ excess map
PSR J
Photon Index Γ
softening
Distance from Pulsar (deg)
IC by high-energy electrons from the pulsar?

26. Previous X-ray study (XMM-Newton)
PSR J (B )
XMM-Newton
0.5-10keV
Pulsar
PWN
H.E.S.S TeV γ excess map
Why is the X-ray image much smaller?
Gaensler et al. 2003
Photon index ~ 2.3
NH~1.4×1022/cm2
LX~3×1033 erg s-1
More extended if observed with high sensitivity?
 Suzaku observation!

27. Suzaku: Very extended PWN
TeV image
XIS 3F 1-9 keV
HESSJ1825
bgd
6arcmin
source
2006/9 50ksec
Suzaku can detect X-rays much more extended than the XMM results.
Uchiyama, H. et al., PASJ, 2009, in print

28. Galactic Ridge X-ray Emission
X-Ray Radial profile
HESSJ1825
Source
Background
1.2×
(CXB+GRXE)
CXB+GRXE
Galactic Ridge X-ray Emission
Unresolved
Point sources
CXB
X-rays are extended at least up to 15 arcmin (~17 pc)

29. X-ray spectra A B C D Region A Region B Region C Region D
Γ=1.78( )
Γ=1.99( )
Γ=2.03 ( )
=pulsar+PWN
HESSJ1825
Reg B-D: no change in photon index.  electrons reach to 17 pc before cooled.
Synchrotron cooling time~1900yrs.Velectron>9000 km/s

30. Suzaku Results X-ray F(TeV)/F(X) Origin extended 34 ? X >55 PWN?
HESS J
extended 34 ?
HESS J X
>55
PWN?
TeV J
2 extended 10
HESS J
2 objects
50 and 25
HESS J O
0.2
SNR CTB37B
efficient acceleration
HESS J
Very extended
1.2
PWN

31. What is the dark accelerators?
Old SNR? (Yamazaki et al. 2006)
Electrons lost their energy by synchrotron cooling.
Protons still keep energy due to small cooling rate.
There should be more unID objects.
(SN rate .. ~1SN/100yr  ~100 unID objects?)
GRB remnants or hyper-nova remnants? (Atoyan et al. 2006)
GRB rate in our Galaxy may be consistent with the number of unID objects.
PWN?
Not clarified! Still mystery!
We need more information from radio to TeV gamma-rays

32. Summary Suzaku results: F(TeV)/F(X) is very large.
Suggesting proton accleration.
X-ray: synchrotron from electrons.
TeV : proton + proton  π0  TeV gamma-rays
Origin is still not clarified.
Old SNR?
GRB remnant?
PWN?
Other object?