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

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)

TeV unidentified objects TeV Galactic Plane Survey (Aharonian et al. 2005, 2006) HESS J1825-137 First example: TeVJ2032+4130 discovered by HEGRA (Aharonian et al. 2002) HESS J1804-216 Many have been discovered in the Galactic Plane with H.E.S.S. Gal. Cent. Spatially extended No counterpart. HESS J1616-508 HESS J1614-518 Dark particle accelerators HESS J1713-381

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

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

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.

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

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)

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

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

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)

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

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

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)

PWN of PSRJ1617-5055? INTEGRAL 18-60keV Landi et al. 2007 XMM-Newton 0.5-10keV 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

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)

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

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?

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, -0.033) XIS FOV 40ks Softest TeV spectrum among the new objects. HESSJ1804

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

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) 50 25 See Bamba et al. 2007, PASJ, 59,　S209 (Suzaku Special Issue No.1)

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

Non-thermal hard X-ray Suzaku 0.3-3.0keV Nakamura, R. et al. PASJ, 2009, in print reg1 reg2 Foreground src Suzaku 3.0-10.0keV Green: TeV (HESSJ1713) Blue: radio White: X-ray (Suzaku) reg1 reg2 Reg1: coincides with the TeV peak Reg2: offset hard emission

Diffuse thermal gas + point source Suzaku 3.0-10.0 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

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 J1825-137 Aharonian et al. 2006 H.E.S.S TeV γ excess map PSR J1826-1334 Photon Index Γ softening Distance from Pulsar (deg) IC by high-energy electrons from the pulsar?

Previous X-ray study (XMM-Newton) PSR J1826-1334 (B1823-13) XMM-Newton 0.5-10keV Pulsar PWN 1arcmin~1pc@4kpc 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!

Suzaku: Very extended PWN TeV image XIS 3F 1-9 keV HESSJ1825 bgd 6arcmin ~6pc@4kpc source 2006/9 50ksec Suzaku can detect X-rays much more extended than the XMM results. Uchiyama, H. et al., PASJ, 2009, in print

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)

X-ray spectra A B C D Region 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) =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

Suzaku Results X-ray F(TeV)/F(X) Origin extended 34 ? X >55 PWN? 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

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

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?