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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)
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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 HESS J1616-508 HESS J1614-518 HESS J1825-137 TeV Galactic Plane Survey (Aharonian et al. 2005, 2006) First example: TeVJ2032+4130 discovered by HEGRA (Aharonian et al. 2002) Many have been discovered in the Galactic Plane with H.E.S.S. HESS J1804-216 Gal. Cent. • Spatially extended • No counterpart. Dark particle accelerators HESS J1713-381
Implications 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) Proton origin π0 Flux ratio (F(TeV)/F(X)) is a key to clarify the particles. Energy
The Suzaku Satellite Hard X-ray Detector (HXD) X-ray Imaging Spectrometer (XIS) X-ray Telescope (XRT) +
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 Clear iron lines 6.4keV 6.7keV 6.9keV XIS spectrum High-energy resolution & High sensitivity (Low BGD)
HESSJ1614-518 HESS TeV γ-ray image (excess map) Brightest among the new objects. XIS FOV 50ks HESSJ1614 (l, b)=(331.52, -0.58)
XIS imageof HESS J1614 Swift XRT also detected (Landi et al. 2006) XIS FI (S0+S2+S3): 3-10keV band Obs. 50ks TeVγ-ray Src A Src B Extended object
XIS spectra 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 HESS TeV image (excess map) XIS FOV 45ks (l, b)=(332.391, -0.138) Provided by S. Funk (MPI) HESSJ1616
XIS image of HESS J1616 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 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 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) 5 1 2 10 2 5 1 10 Energy (keV) Energy (keV) F(TeV)/F(X; src1 or src2) = 10 proton acceleration in TeV J2032?
HESSJ1804-216 HESS TeV γ-ray image (excess map) Softest TeV spectrum among the new objects. XIS FOV 40ks (l, b)=(8.401, -0.033) Provided by S. Funk (MPI) HESSJ1804
XIS image of HESS J1804 Swift XRT (Landi et al. 2006) Chandra (Kargaltsev et al. 2007) src2 src1 XIS FI (S0+S2+S3): 3-10keV TeV image Src1: point src Src2: extended (Bamba et al. 2007) Chandra (Kargaltsev et al. 2007) 40ks
XIS spectra HESSJ1804 src2 src2: extended src1 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) 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 Reg1: coincides with the TeV peak Reg2: offset hard emission reg2
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 J1825-137 H.E.S.S TeV γ excess map PSR J1826-1334 30arcmin~30pc @4kpc Aharonian et al. 2006 • Spin-down luminosity • ~ 2.8×1036 erg s-1 • Characteristic age • 21.4 kyr (Clifton 1992) • D~4kpc HESS J 1825-137 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 H.E.S.S TeV γ excess map 1arcmin~1pc@4kpc 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!
XIS 3F 1-9 keV Suzaku: Very extended PWN TeV image 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
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)
A B Region B Region A C D Γ=1.99(1.91-2.08) Γ=1.78(1.68-1.88) Region C Region D Γ=2.03 (1.95-2.14) Γ=2.03 (1.95-2.14) X-ray spectra =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
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?