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Suzaku Observations of HESS sources

Hironori Matsumoto (Kyoto Univ.)

Hideki Uchiyama (Kyoto Univ.), Aya Bamba, Ryoko Nakamura, Takayasu Anada (ISAS/JAX

A), and the Suzaku team

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Outline• HESS unID objects: “Dark particle accelerators”• Suzaku Observations

– HESSJ1614-518– HESSJ1616-508– HESSJ1713-381 (CTB37B)– HESSJ1804-216– HESSJ1825-137– HESSJ1837-069

• Summary

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HESS Galactic Plane Survey

First systematic Galactic plane survey with TeV γ-ray (>200GeV)

New TeV objects with no obvious counterpart.

(Aharonian et al. 2005, 2006)

HESSJ1804-216

HESSJ1616-508

HESSJ1614-518

Gal. Cent.

HESSJ1713-381

HESSJ1837-069

Dark particle accelerators

HESSJ1825-137

4/25

HESSJ1614-518

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

HESS TeV γ-ray image (excess map)

XIS FOV50ks

Brightest among the new objects.

HESSJ1614

5/25

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

Extended object

TeVγ-ray

XIS image

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

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H.E.S.S.

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.

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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 imageXIS 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

10/25

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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PSRJ1617-5055?INTEGRAL 18-60keV

PSRJ1617

Landi et al. 2007

XMM-Newton 0.5-10keV

PSRJ1617

Why is there no trace in X-ray band?Why is there no clear PWN in the radio (Kaspi et al. 1998) and X-ray bands?

SNR RCW103

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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 2008 in preparationSuzaku 0.3-3.0keV

Suzaku 3.0-10.0keV

Green: TeV (HESS)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

•Thermal (kT=0.9keV)+PL(Γ=3.0)•A point source discovered by Chandra (Aharonian et 1l. 2008) contributes much to the PL component.

Hard PL (Γ=1.5) + Leakage from reg1 due to PSF.•Roll-off energy > 15keV•The hard PL suggests efficient acceleration.

F(TeV)/F(X)~0.2 B~8uG assuming IC.Emax > 170 TeV

15/25

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

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

src1

src2

src1: point-likesrc2: extended or multiple

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

18/25

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!

20/25

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

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1.2×(CXB+GRXE)

CXB+GRXE

Galactic Ridge X-ray Emission

CXB

BackgroundSource

Radial profile

UnresolvedPoint sources

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

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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 15pc before cooled.

=pulsar+PWN

Synchrotron cooling time~1400yrs.Velectron~10000 km/s

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HESSJ1837-069

HESS image

INTEGRAL/ISGRI(Malizia et al. 2005)

1degx1deg

X-rays were detected up to 300 keV by INTEGRAL

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AXJ1838.0-0655

AXJ1837.3-0652

X-ray counterparts are offset from the TeV gamma-ray peak.

TeV peak

Pulsations of 70.5 ms were recently discovered from AXJ1838 with RXTE (Gotthelf et. al. 2008).

Offset pulsar wind nebulaAnada et al. in preparation

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SummaryX-ray Origin

HESSJ1614-518 O ?

HESSJ1616-508 X ?

HESSJ1713-381 O SNR CTB37B

Efficient acceleration

HESSJ1804-216 2 ?

HESSJ1825-137 Very extended PWN

HESSJ1837-069 2 extended Offset PWN

Can you construct a “Grand Unification Theory (GUT)” of the dark particle accelerators?