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X-ray Observations of the Dark Particle Accelerators

Hironori Matsumoto (Kyoto Univ.)

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Outline• TeV unID objects: “Dark particle accelerators”• The Suzaku satellite• Suzaku Observations

– HESS J1614-518– HESS J1616-508– TeV J2032+4130– HESS J1804-216– HESS J1713-381 (SNR CTB37B)– HESS J1825-137 　 (PWN)

• Summary

(with ID objects)

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TeV unidentified objects

•Spatially extended •No counterpart.

TeV Galactic Plane Survey(Aharonian et al. 2005, 2006)

HESS J1804-216

HESS J1616-508

HESS J1614-518

Gal. Cent.

HESS J1713-381Dark particle accelerators

HESS J1825-137First example: TeVJ2032+4130 discovered by HEGRA(Aharonian et al. 2002)

Many have been discovered in the Galactic Plane with H.E.S.S.

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Implications

What particles are accelerated, protons or electrons?

Electrons emit synchrotron X-rays very easily!

Electron origin

E2 f

(E)

E2 f

(E) Energy

Energy

π0

X-ray TeV

Proton origin

Synch IC

If electrons,X-ray … synchrotronTeV … Inverse Compton of CMB

Flux(TeV)/F(X)=U(CMB)/U(B)~1 with a few micro Gauss

Flux ratio (F(TeV)/F(X)) is a key to clarify the particles.

TeV gamma-rays High-energy particles!

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The Suzaku SatelliteHard X-ray Detector (HXD)

X-ray Telescope (XRT) X-ray Imaging Spectrometer (XIS)

+

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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.

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GC spectrum6.4keV

6.7keV

6.9keV

Clear iron lines

XIS spectrum

High-energy resolution & High sensitivity (Low BGD)

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HESSJ1614-518

(l, b)=(331.52, -0.58)

HESS TeV γ-ray image (excess map)

XIS FOV50ks

Brightest among the new objects.

HESSJ1614

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XIS FI (S0+S2+S3): 3-10keV band

Extended object

TeVγ-ray

XIS image　 of HESS J1614

Swift XRT also detected(Landi et al. 2006)

Obs. 50ks

Src A

Src B

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XIS spectra

NH=1.2(±0.5)e22cm-2

Γ=1.7(±0.3）F(2-10keV)=5e-13erg/s/cm2

NH=1.2(±0.1)e22cm-2

Γ=3.6(±0.2）F(2-10keV)=3e-13erg/s/cm2

•Featurelessnon-thermal

Featureless,but extremely soft

Src A

Src B

Src A spectrum

Src B spectrum

HESS J1614

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src A

B=10μG

B=1μG

B=0.1μG

Src A

Src B

Src AF(1-10TeV)/F(2-10keV)=34

Plausible X-ray counterpart: src A

Matsumoto et al. 2008, PASJ, 60. S163 (Suzaku special issue No.2)

•Difficult to explain both the TeV gamma-ray and X-ray from the electron origin.•The origin of srcA is not clarified.

HESS J1614

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HESSJ1616-508HESS TeV image (excess map)

(l, b)=(332.391, -0.138)

XIS FOV45ks

Provided by S. Funk (MPI)

HESSJ1616

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XIS image of HESS J1616XIS FI (S0+S2+S3): 3—12keV

•No X-ray counterpart•F(2-10keV)<3.1e-13 erg/s/cm2

TeV image

45ks F(TeV)/F(X)>55

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If we assume electrons…

Very weak B(B<1μGauss)

HESSJ1616 SED

Suzaku upper limit

Strong cut-offorrealistic?

Matsumoto et al. 2007, PASJ, 59, 199 　 (Suzaku Special Issue No.1)

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PWN of PSRJ1617-5055?INTEGRAL 18-60keV

PSRJ1617

Landi et al. 2007

XMM-Newton 0.5-10keV

PSRJ1617

Neither radio (Kaspi et al. 1998) nor X-ray has detected the PWN.Why is there no X-rays bridging the pulsar and HESSJ1616?

SNR RCW103

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TeV J2032+4130HEGRA TeV gamma-ray image

Aharonian et al. (2005)

•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.

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Suzaku observation of TeV J2032December 2007, 40ks obs.

Two extended X-ray objects

src1src2

Murakami, H. et al., in preparation

TeV region

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X-ray spectrum of the sources

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 2.0

Both sources show power-law spectra.

src1 src2

Energy (keV)Energy (keV)

1 2 5 10 10521

Murakami et al., in preparation

Point sources(Chandra)

Point sources(Chandra)

F(TeV)/F(X; src1 or src2) = 10proton acceleration in TeV J2032?

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HESSJ1804-216HESS TeV γ-ray image (excess map)

Provided by S. Funk (MPI)(l, b)=(8.401, -0.033)

XIS FOV40ks

Softest TeV spectrum among the new objects.

HESSJ1804

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XIS image of HESS J1804

XIS FI (S0+S2+S3): 3-10keV

src1

src2

Src1: point srcSrc2: extended(Bamba et al. 2007)

TeV image

40ks

Swift XRT (Landi et al. 2006)Chandra (Kargaltsev et al. 2007)

Chandra (Kargaltsev et al. 2007)

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XIS spectra

src1

src2

src1: point-like

src2: extended

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

See Bamba et al. 2007, PASJ, 59, 　 S209 (Suzaku Special Issue No.1)

F(TeV)/F(X) 50 25

HESSJ1804

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HESSJ1713-381 (CTB37B)

SNR CTB37B

HESSJ1713-381 coincides with the SNR CTB37B

Color: TeVWhite: radio

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Non-thermal hard X-rayNakamura, R. et al. PASJ, 2009, in printSuzaku 0.3-3.0keV

Suzaku 3.0-10.0keV

Green: TeV (HESSJ1713)Blue: radioWhite: X-ray (Suzaku)

reg1

reg1

reg2

reg2

Foreground src

Reg1: coincides with the TeV peakReg2: offset hard emission

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Suzaku 3.0-10.0 keVreg1

reg2•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

HESSJ1713

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HESS J 1825-137

30arcmin~30pc@4kpc

HESS J1825-137

Aharonian et al. 2006

H.E.S.S TeV γ excess map

PSR J1826-1334

Distance from Pulsar (deg)

Pho

ton

Inde

x Γ

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

softening

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Previous X-ray study (XMM-Newton)PSR J1826-1334 (B1823-13)

Photon index ~ 2.3NH~1.4×1022/cm2 LX~3×1033 erg s-1

1arcmin~1pc@4kpc

Pulsar

PWN

XMM-Newton0.5-10keV

H.E.S.S TeV γ excess map

Gaensler et al. 2003 Why is the X-ray image much smaller?

More extended if observed with high sensitivity? Suzaku observation!

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Suzaku: Very extended PWN

XIS 3F 1-9 keV

source

6arcmin~6pc@4kpc

2006/9 50ksec

bgd

Suzaku can detect X-rays much more extended than the XMM results.

TeV image

Uchiyama, H. et al., PASJ, 2009, in print

HESSJ1825

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1.2×(CXB+GRXE)

CXB+GRXE

Galactic Ridge X-ray Emission

CXB

BackgroundSource

X-Ray Radial profile

UnresolvedPoint sources

X-rays are extended at least up to 15 arcmin (~17 pc)

HESSJ1825

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X-ray spectraRegion A Region B

Region C Region D

Γ=1.78(1.68-1.88) Γ=1.99(1.91-2.08)

Γ=2.03 (1.95-2.14) Γ=2.03 (1.95-2.14)

A

BC

D

Reg B-D: no change in photon index. electrons reach to 17 pc before cooled.

=pulsar+PWN

Synchrotron cooling time~1900yrs.Velectron>9000 km/s

HESSJ1825

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Suzaku ResultsX-ray F(TeV)/F(X) Origin

HESS J1614-518 extended 34 ?

HESS J1616-508 X >55 PWN?

TeV J2032+4130 2 extended 10 ?

HESS J1804-216 2 objects 50 and 25 ?

HESS J1713-381 O 0.2 SNR CTB37B

efficient acceleration

HESS J1825-137 Very extended 1.2 PWN

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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?

We need more information from radio to TeV gamma-rays

Not clarified! Still mystery!

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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?