1/32 x-ray observations of the dark particle accelerators hironori matsumoto (kyoto univ.)
Post on 15-Jan-2016
222 views
TRANSCRIPT
1/32
X-ray Observations of the Dark Particle Accelerators
Hironori Matsumoto (Kyoto Univ.)
2/32
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)
3/32
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.
4/32
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!
5/32
The Suzaku SatelliteHard X-ray Detector (HXD)
X-ray Telescope (XRT) X-ray Imaging Spectrometer (XIS)
+
6/32
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.
7/32
GC spectrum6.4keV
6.7keV
6.9keV
Clear iron lines
XIS spectrum
High-energy resolution & High sensitivity (Low BGD)
8/32
HESSJ1614-518
(l, b)=(331.52, -0.58)
HESS TeV γ-ray image (excess map)
XIS FOV50ks
Brightest among the new objects.
HESSJ1614
9/32
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
10/32
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
11/32
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
12/32
HESSJ1616-508HESS TeV image (excess map)
(l, b)=(332.391, -0.138)
XIS FOV45ks
Provided by S. Funk (MPI)
HESSJ1616
13/32
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
14/32
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)
15/32
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
16/32
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.
17/32
Suzaku observation of TeV J2032December 2007, 40ks obs.
Two extended X-ray objects
src1src2
Murakami, H. et al., in preparation
TeV region
18/32
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?
19/32
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
20/32
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)
21/32
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
22/32
HESSJ1713-381 (CTB37B)
SNR CTB37B
HESSJ1713-381 coincides with the SNR CTB37B
Color: TeVWhite: radio
23/32
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
24/32
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
25/32
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
26/32
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!
27/32
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
28/32
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
29/32
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
30/32
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
31/32
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!
32/32
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?