X-ray Observations of the Dark Particle Accelerators
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Transcript of X-ray Observations of the Dark Particle Accelerators
2/25
Outline• TeV unID objects: “Dark particle accelerators”• The Suzaku satellite• Suzaku Observations
– HESS J1614-518– HESS J1616-508– TeV J2032+4130– HESS J1713-381 (CTB37B)– HESS J1804-216– HESS J1825-137– HESS J1837-069
• Summary
3/25
TeV unidentified objects
Many new TeV objects with no obvious counterpart.
TeV Galactic Plane Survey(Aharonian et al. 2005, 2006)
HESS J1804-216
HESS J1616-508
HESS J1614-518
Gal. Cent.
HESS J1713-381
HESS J1837-069
Dark particle accelerators
HESS J1825-137
First example: TeVJ2032+4130 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
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!
5/25
The Suzaku SatelliteHard 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
HESSJ1614-518
(l, b)=(331.52, -0.58)
HESS TeV γ-ray image (excess map)
XIS FOV50ks
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/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
10/25
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.
11/25
HESSJ1616-508HESS TeV image (excess map)
(l, b)=(332.391, -0.138)
XIS FOV45ks
Provided by S. Funk (MPI)
HESSJ1616
12/25
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
13/25
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)
14/25
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
15/25
TeV J2032+4130HEGRA 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 observationDecember 2007, 40ks obs.
Two extended X-ray objects
src1src2
Murakami et al., in preparation
17/25
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) = 10Suggesting proton acceleration.
18/25
HESSJ1713-381 (CTB37B)
SNR CTB37B
HESSJ1713-381 coincides with the SNR CTB37B
Color: TeVWhite: radio
19/25
Non-thermal hard X-rayNakamura et al. PASJ in printSuzaku 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
20/25
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).•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
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
22/25
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)
23/25
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
24/25
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
25/25
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!
26/25
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
Uchiyama et al., PASJ, 2009, in print
27/25
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 (~17 pc)
28/25
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
29/25
Suzaku ResultsX-ray F(TeV)/F(X) Origin
HESS J1614-518 extended 34 ?
HESS J1616-508 X >55 ?
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
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
HESSJ1837-069
HESS image
INTEGRAL/ISGRI(Malizia et al. 2005)
1degx1deg
X-rays were detected up to 300 keV by INTEGRAL
33/25
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