1. Joint Discussion on the Highest-Energy Gamma-Ray Universe observed with Cherenkov Telescpe Arrays
The multi-wavelength context of the future gamma-ray instruments: X-rays
T. Dotani1), A. Bamba2), T. Fujinaga3,1)
1) ISAS/JAXA
2) Aoyama Gakuin Univ.
3) Tokyo Institute of Technology

2. CONTENTS Current/Future X-ray missions
NuSTAR, ASTROSAT, eROSITA, LOFT
ASTRO-H
Science cases : X-ray studies of VHE -ray sources
Shell-type SNRs
PWNe
Blazars

3. Complementarity of X-ray & VHE -ray bands
Examples of SEDs from mono-energetic electrons/protons
(Hinton, J.A., Hofmann, W., ARAA, 47, 523)
1-10 keV
1-10 TeV
E2dN/dE (erg/cm2/sec)
Dashed curveは、bremssstrahlung。Inverse Comptonは、３種類のseed photonについて表示：CMB, dust-emitted FIR (0.02 eV)、visible light (1.5eV)。 100 TeVの可視光に対するICは、
ほぼδ-function。The curve normalizations are appropriate for a total particle energy of 10^48 erg at 1 kpc distance in a magnetic field of 3 μG, a matter density of 100 hydrogen atoms cm−3
and radiation fields of density 0.26 eV cm−3 (CMB and FIR) and 1 eV cm−3 (starlight)
b) SEDs for γ rays and synchrotron radiation of secondary electrons from strong interactions of mono-energetic protons. The magnetic field is increased to 30 μG to illustrate the effects
of cooling and steady injection over 104 years (dashed curves 105 years) is assumed.

4. CTA schedule 2010 2015 2020 Preparatory phase Construction/Deployment
Partial Operation
Full Operation

5. X-ray satellites in these 10 years
2010
2015
2020
CTA
Chandra
XMM-Newton
Suzaku
NuSTAR
eROSITA/SRG : 打ち上げは2013 Nov
ASTROSAT
eROSITA/SRG
ASTRO-H
LOFT

6. NuSTAR Launched successfully on June 13th, 2012.
The first satellite-based focusing X-ray telescope operating in the hard X-ray band, 5-80 keV.
Leading institution : Caltech
Mission life : 2 years baseline
Integral
NuSTAR
Leading institution is Caltech. Mission life : 2 years
Deployable mast
Focal length 10m

7. ASTROSAT
The first dedicated astronomy mission in India for multi-wavelength astronomy.
Launch : 2013
Main instrument : large area proportional counter (6000 cm2)
LAXPC

8. eROSITA / SRG
eROSITA will be the primary instrument on-board the Russian "Spectrum-Roentgen-Gamma" (SRG) satellite.
Purpose : First imaging all-sky survey
up to 10 keV
Launch : 2013
Leading institution : MPE

9. LOFT : the Large Observatory For X-ray Timing
One of the four candidates selected for the next M-class mission in ESA’s Cosmic Vision.
Current status : Assessment phase
Launch period : (if selected)
Instruments
The Large Area Detector keV)
The Wide Field Monitor
The Director has now selected four missions to undergo an initial Assessment Phase. Once this is completed, a further down-selection will be performed, leading to a decision on which mission will be finally implemented.

10. ASTRO-H Suzaku 14m H2A Length :14 m Weight : 2.7 t Power : 3500 W
Telemetry : 8Mbps (X-band)
Data Recorder : 12 Gbits
Launch : 2014
Life : 3 year (requirement)
5 year (goal)
14m
H2A 10 10

11. ASTRO-H mission instruments11 11

12. Filter wheel

13. SXS: cooling chain
Life
3 years with LHe
2 more years without LHe

14. SXS performance compared with existing observatories
Figure of merit
Effective area

15. SXI: an X-ray CCD camera
4 CCD chips with 31x31mm
Depletion layer: 200m
Type: Back-illumination
Operating temp.: degC
Exposure time: 4 sec
FOV: 38x38 arcmin
Engineering model
Hood
A focal plane assembly
Frontend
Electronics
box
SXI

16. Hard X-ray telescopes & imagers
HXT principle

17. HXI: hard X-ray imagers
principle
BGO scintillaters
Engineering model

18. SGD BGO fov Principle SGD Fine collimator fov
Narrow field Compton camera AE
Fine collimator
Satellite side panel
BGO
BGO
SGD
Compton camera

19. ASTRO-H sensitivities in hard X-ray band
keV
MeV
GeV
TeV
10-4
INTEGRAL
Suzaku
SGD
SGD
HXI
CTA
HXI
10-8 10
100
104
106
1010
1012
1000
Energy (keV)
Energy (eV)

20. VHE -ray sky
Galactic (61): PWN (19), -ray binary (4), SNR(10), GC (1), Pulsar (1), OC (1), unID (24)
Extra-galactic (46) : Blazar (37), FSRG (2), Radio galaxy (5), SB galaxy (2)

21. Origin of cosmic rays below ~1015 eV − Particle acceleration in shell type SNRs? −
G (RX J ): shell-type SNR
Model spectrum for the hadronic scenario
TeV image with HESS
SN1006に似たshell-type SNR. RX J とも。中心にCOOがあることから、core-collapse SNRと考えられる。EGRET source 3EG J が近くにあるものの、error regionの外。
ICでもwide band spectrumの説明が可能だが、Xを強くしすぎないためにfilling factor を小さくする必要がある。Uchiyama et alで、年単位の
変化がChandraで観測された事から、磁場の強度を見積もると、1mGになる。
Contours : ASCA
Yuan, Q. et al. 2011, ApJ, 735, 120

22. Acceleration in thin filamentsG
Chandra
SN1006
Chandra
Uchiyama et al.: 磁場の強さは、〜1mG。また、η~1（Bohm limitが成立）。線形理論では、η~(ΔB/B)^-2 >> 1。
Red : keV
Cyan : keV
Blue : keV
Uchiyama et al. 2007, Nature, 449, 576

23. Expected image with A-H/HXI
Structure of the particle acceleration site in the filaments may be studied with NuSTAR and A-H/HXI at an order of magnitude higher energies.
Simulated image of A-H/SXI
(9x9 arcmin2)

24. Measuring the ion temperature in shell type SNR
NW shell : thermal X-rays
Kinematic energy of shocked plasma
Kinematic energy of unshocked plasma
Thermal energy of shocked plasma
Shock velocity is known
(2890 km/s)
Particle acceleration
ASTRO-H SXS can measure the thermal energy (ion temp) of shocked plasma
Measure the particle acceleration efficiency

25. Evolution of particle acceleration in the shell-type SNRs
<1000 years
years
>3000 years
Stefan Funk, August 5th 2011, TeVPA

26. Evolution of Synchrotron X-rays in SNRs
Synchrotron X-rays tends to drop for SNRs with >5pc.
Radius : indicator of age
Nakamura et al. 2012, ApJ, 746, 134

27. Evolution of Synchrotron X-rays in SNRs
Assumption (electrons)
acceleration time = synchrotron cooling time
TeV
protons
0.1 cm-3
1 cm-3
Assumption (protons)
Acceleration time = SNR age
5 cm-3
electrons

28. Diffusion of energetic electrons in PWNe
G (HESS J ) : spectral steepening away from the pulsar
Right figure
● Using BG estimate from same FOV, ○ Using BG estimate from off data.
Produced by S. Funk and O.C. de Jager for the H.E.S.S. collaboration

29. An example of X-ray observations
The Kookaburra complex
HESS J
Suzaku X-ray image K3
PSR J
(P=68ms)
R1 & R2
HESS J
H.E.S.S. contours
Rabbit

30. Spatial dependence of the X-rays in the PWN
Energy spectra tend to become softer according to the distance from the X-ray peaks (pulsars).
Energy loss of electrons/positrons due to the synchrotron radiation (Compton scattering) as they propagate. K3
Rabbit

31. Spatial dependence of the X-rays in the PWN (2)
HESS J
(Kes75)
HESS J
(G )
HESS J
HESS J
(G )
(G )
HESS J
HESS J
HESS J
HESS J
　Radio pulsar (82.7 ms) at the cross.
　Spatial variation of the VHE photon index is suggested by H.E.S.S.
HESS A B C D
Photon index 2
2.5 A B D C

32. Suzaku observations of HESS J1809-193
0.4-1 keV
2-10 keV
　X-ray source at the position of the pulsar
　Different spatial distribution between thermal （0.4-1 keV） and non-thermal X-ray emission.
HESS
Energy spectra were calculated for annular regions (A through D)

33. HESS J1809-193 : spectral analysis
Spectral model : Power-law + thin thermal X-ray emission
NH = 7.1 ×1021 cm-2
kT = 0.18 keV A B C D
Pulsar
Far
1.5
2.0
Photon index
No spatial dependence was found in the spectral shape

34. HESS J1809-193 : spatial extent
Measure the extension of non-thermal X-ray emission around the pulsar ０ ５ １０ １５ ２０
Distance from the pulsar (arcmin)
Suzaku １
2-10 keV
Relative intensity
0.5
pulsar
Projected intensity profile in the rectangle region
Fit with a gaussian + constant
σ = 6’.8 ± 1’.0
Pseudo-color map : 2-10 keV X-ray intensity
Yellow contours : HESS image

35. Spatial extent of the non-thermal emission
Suzaku
Chandra
HESS J
PSR J
σ = 3’.5 ± 0’.4
σ = 1’.5 ± 0’.4
ASCA
Vela X
MSH 15-52
Chandra
σ = 23’.5 ± 2’.6
σ = 1’.6 ± 0’.1 35

36. Spatial extent of the non-thermal emission
Suzaku
Kes 75
Chandra
HESS J
σ = 0’.63 ± 0’.05
σ = 4’.2± 0’.5 G
Chandra
XMM-Newton
HESS J
σ = 0’.91 ± 0’.05
σ = 1’.8 ± 0’.5

37. Spatial extent of the non-thermal diffuse X-ray emission vs pulsar ages
X-ray emitting electrons
Energy loss time scale
Accelerated electrons up to ~80 TeV can escape from the PWNe without losing most of the energies.

38. VHE -ray sky
Galactic (61): PWN (19), -ray binary (4), SNR(10), GC (1), Pulsar (1), OC (1), unID (24)
Extra-galactic (46) : Blazar (37), FSRG (2), Radio galaxy (5), SB galaxy (2)

39. Multi-frequency studies of Blazars
Blazar sequence
　　Radio
　　Optical
X-ray
GeV
TeV
Flat Spectrum Radio Quasars
(= FSRQ,
e.g. PKS )
1-10 keV
1-10 TeV
X-ray band is suited to detect luminous FSRQs
ERC
Sync
SSC
Low-frequency peaked
BL Lac　
(= LBL e.g., )
High-frequency peaked
BL Lac　
(= HBL e.g., Mrk421)
Low-energy peak
(Synchrotron)
High-energy peak
（Inverse Compton） LE HE
Kataoka 02 Kubo+ 98

40. High power jets : Luminous FSRQ
PKS
Fermi LAT
LX > 2x1047 erg/sec
(>109 Msolar SMBH)
HXI 100ks
The best-fit synchrotron-Compton model for PKS
CTA
The model is shifted to z~8.
Astro-H can detect wide-band spectrum of effectively all the luminous FSRQs.
Soft X-ray
Hard X-ray
Evolution of FSRQs
Ghisellini et al. 2010, MNRAS, 405, 387

41. CXB and contribution of the FSRQs
FSRQs may explain the CXB at >500 keV solving the mystery of generation of the MeV background.
FSRQs
(double power-law is assumed)
Seyfert-like AGNs
Ajello, M. et al. 2009, ApJ, 699, 603

42. Summary
ASTRO-H may be the only observatory-class X-ray satellite operating simultaneously with CTA.
Combining ASTRO-H and CTA data, we may be able to trace history of particle acceleration, acceleration efficiency, and diffusion of energetic particles in SNRs and PWNe.
HXI on board ASTRO-H may be powerful telescopes to observe luminous FSRQs, which are key to understand CXB in the MeV band.