1/25 X-ray Observations of the Dark Particle Accelerators Hironori Matsumoto (Kyoto Univ.)

2/25 Outline TeV unID objects: “Dark particle accelerators” The Suzaku satellite Suzaku Observations –HESS J –HESS J –TeV J –HESS J (CTB37B) –HESS J –HESS J –HESS J Summary

3/25 TeV unidentified objects Many new TeV objects with no obvious counterpart. TeV Galactic Plane Survey (Aharonian et al. 2005, 2006) HESS J HESS J HESS J Gal. Cent. HESS J HESS J Dark particle accelerators HESS J First example: TeVJ discovered by HEGRA (Aharonian et al. 2002)

4/25 Implications What particles are accelerated, protons or electrons? Electrons emit synchrotron X-rays very easily! Electron origin E 2 f(E) Energy π0π0 X-rayTeV Proton origin Synch IC If electrons, X-ray … synchrotron TeV … 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!

5/25 The Suzaku Satellite Hard X-ray Detector (HXD) X-ray Telescope (XRT) X-ray Imaging Spectrometer (XIS) +

6/25 Onboard Detectors X-ray Telescope (XRT) + X-ray Imaging Spectrometer (XIS) Mirror + CCD E=0.3—10keV 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) Suzaku is the best tool for studying dim and diffuse objects.

7/25 HESSJ (l, b)=(331.52, -0.58) HESS TeV γ-ray image (excess map) XIS FOV 50ks Brightest among the new objects. HESSJ1614

8/25 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

9/25 XIS spectra NH=1.2(±0.5)e22cm -2 Γ=1.7(±0.3 ） F(2-10keV)=5e-13erg/s/cm 2 NH=1.2(±0.1)e22cm -2 Γ=3.6(±0.2 ） F(2-10keV)=3e-13erg/s/cm 2 Featureless  non-thermal Featureless, but extremely soft Src A Src B Src A spectrum Src B spectrum

10/25 H.E.S.S. src A B=10μG B=1μG B=0.1μG Src A Src B Src A F(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.

11/25 HESSJ HESS TeV image (excess map) (l, b)=( , ) XIS FOV 45ks Provided by S. Funk (MPI) HESSJ1616

12/25 XIS image XIS FI (S0+S2+S3): 3 — 12keV No X-ray counterpart F(2-10keV)<3.1e-13 erg/s/cm 2 TeV image 45ks F(TeV)/F(X)>55

13/25 If we assume electrons… Very weak B (B<1μGauss) HESSJ1616 SED Suzaku upper limit Strong cut-off or realistic? Matsumoto et al. 2007, PASJ, 59, 199 (Suzaku Special Issue No.1)

14/25 PSRJ ? INTEGRAL 18-60keV PSRJ1617 Landi et al XMM-Newton keV 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

15/25 TeV J HEGRA TeV gamma-ray image Aharonian et al. (2005) First TeV unID object discovered with the HEGRA telescope. Cygnus region. Close to Cyg OB2 (OB stars) Cyg X-3 (micro-QSO) EGRET source Extended (~6arcmin)

16/25 Suzaku observation December 2007, 40ks obs. Two extended X-ray objects src1 src2 Murakami et al., in preparation

17/25 X-ray spectrum of the sources N H (10 22 cm -2 ) ΓF X ( erg s -1 cm -2 ) Src Src Both sources show power-law spectra. src1src2 Energy (keV) Murakami et al., in preparation Point sources (Chandra) Point sources (Chandra) F(TeV)/F(X; src1 or src2) = 10  Suggesting proton acceleration.

18/25 HESSJ (CTB37B) SNR CTB37B HESSJ coincides with the SNR CTB37B Color: TeV White: radio

19/25 Non-thermal hard X-ray Nakamura et al. PASJ in print Suzaku keV Suzaku keV Green: TeV (HESS) Blue: radio White: X-ray (Suzaku) reg1 reg2 Foreground src Reg1: coincides with the TeV peak Reg2: offset hard emission

20/25 Suzaku keV reg1 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). Roll-off energy > 15keV The hard PL suggests efficient acceleration. F(TeV)/F(X)~0.2  B~8uG assuming IC. Emax > 170 TeV

21/25 HESSJ 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

22/25 XIS image XIS FI (S0+S2+S3): 3-10keV src1 src2 src1: point-like src2: extended or multiple TeV image 40ks Swift XRT (Landi et al. 2006) Chandra (Kargaltsev et al. 2007)

23/25 XIS spectra src1 src2 src1: point-like src2: extended src1src2 Γ-0.3±0.51.7±1.2 NH (10 22 cm -2 ) 0.2(<2.2)11±8 F(2-10keV) erg/s/cm See Bamba et al. 2007, PASJ, 59, S209 (Suzaku Special Issue No.1) F(TeV)/F(X) 50 25

24/25 HESS J HESS J Aharonian et al H.E.S.S TeV γ excess map PSR J Distance from Pulsar (deg) Photon Index Γ IC by high-energy electrons from the pulsar? Spin-down luminosity ~ 2.8×10 36 erg s -1 Characteristic age 21.4 kyr (Clifton 1992) D~4kpc softening

25/25 Previous X-ray study (XMM-Newton) PSR J (B ) Photon index ~ 2.3 NH~1.4×10 22 /cm 2 L X ~3×10 33 erg s -1 Pulsar PWN XMM-Newton keV H.E.S.S TeV γ excess map Gaensler et al Why is the X-ray image much smaller? More extended if observed with high sensitivity?  Suzaku observation!

26/25 Suzaku: Very extended PWN XIS 3F 1-9 keV source 6arcmin 2006/9 50ksec bgd Suzaku can detect X-rays much more extended than the XMM results. TeV image Uchiyama et al., PASJ, 2009, in print

27/25 1.2× (CXB+GRXE) CXB+GRXE Galactic Ridge X-ray Emission CXB Background Source Radial profile Unresolved Point sources X-rays are extended at least up to 15 arcmin (~17 pc)

28/25 X-ray spectra Region A Region B Region C Region D Γ=1.78( ) Γ=1.99( ) Γ=2.03 ( ) A B C 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

29/25 Suzaku Results X-rayF(TeV)/F(X)Origin HESS J extended34? HESS J X>55? TeV J extended10? HESS J objects50 and 25? HESS J O0.2SNR CTB37B efficient acceleration HESS J Very extended1.2PWN

30/25 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!

31/25 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 not still clarified. –Old SNR? –GRB remnant? –PWN? –Other object?

32/25 HESSJ HESS image INTEGRAL/ISGRI (Malizia et al. 2005) 1degx1deg X-rays were detected up to 300 keV by INTEGRAL

33/25 AXJ AXJ 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 nebula Anada et al. in preparation

34/25 Summary X-rayF(TeV)/F(X)Origin HESS J extended34? HESS J X>55? TeV J extended~10? HESS J O0.2SNR CTB37B efficient acceleration HESS J objects50 and 25? HESS J Very extended1.2PWN HESS J extended1.4 and 8.2Offset PWN