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
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
Complementarity of X-ray & VHE -ray bands Examples of SEDs from mono-energetic electrons/protons (Hinton, J.A., Hofmann, W., 2009. 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.
CTA schedule 2010 2015 2020 Preparatory phase Construction/Deployment Partial Operation Full Operation
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
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
ASTROSAT The first dedicated astronomy mission in India for multi-wavelength astronomy. Launch : 2013 Main instrument : large area proportional counter (6000 cm2) LAXPC
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 http://www.mpe.mpg.de/455784/science
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 : 2020-2022 (if selected) Instruments The Large Area Detector (10m2@8 keV) The Wide Field Monitor http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=48467 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. http://www.isdc.unige.ch/loft/index.php/the-loft-mission
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
ASTRO-H mission instruments 11 11
Filter wheel
SXS: cooling chain Life 3 years with LHe 2 more years without LHe
SXS performance compared with existing observatories Figure of merit Effective area
SXI: an X-ray CCD camera 4 CCD chips with 31x31mm Depletion layer: 200m Type: Back-illumination Operating temp.: -120 - -100 degC Exposure time: 4 sec FOV: 38x38 arcmin Engineering model Hood A focal plane assembly Frontend Electronics box SXI
Hard X-ray telescopes & imagers HXT principle
HXI: hard X-ray imagers principle BGO scintillaters Engineering model
SGD BGO fov Principle SGD Fine collimator fov Narrow field Compton camera AE Fine collimator Satellite side panel BGO BGO SGD Compton camera
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)
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) http://www.mpp.mpg.de/~rwagner/sources/
Origin of cosmic rays below ~1015 eV − Particle acceleration in shell type SNRs? − G347.3-0.5 (RX J1713.7-3946): shell-type SNR Model spectrum for the hadronic scenario TeV image with HESS SN1006に似たshell-type SNR. RX J1713.7-3946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 J1714-3857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
Acceleration in thin filaments G347.3-0.5 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。 http://chandra.harvard.edu/photo/2005/sn1006/ Red : 0.5-0.91 keV Cyan : 0.91-1.34 keV Blue : 1.34-3.0 keV Uchiyama et al. 2007, Nature, 449, 576
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)
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
Evolution of particle acceleration in the shell-type SNRs <1000 years 1000-3000 years >3000 years Stefan Funk, August 5th 2011, TeVPA
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
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
Diffusion of energetic electrons in PWNe G18.0-0.7 (HESS J1825-137) : 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
An example of X-ray observations The Kookaburra complex HESS J1420-607 Suzaku X-ray image K3 PSR J1420-6048 (P=68ms) R1 & R2 HESS J1418-609 H.E.S.S. contours Rabbit
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
Spatial dependence of the X-rays in the PWN (2) HESS J1846-029 (Kes75) HESS J1833-105 (G21.5-0.9) HESS J1809-193 HESS J1747-281 (G0.9+0.1) (G18.0-0.7) HESS J1825-137 HESS J1837-069 HESS J1804-216 HESS J1809-193 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
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)
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
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
Spatial extent of the non-thermal emission Suzaku Chandra HESS J1825-137 PSR J1420-6049 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
Spatial extent of the non-thermal emission Suzaku Kes 75 Chandra HESS J1718-385 σ = 0’.63 ± 0’.05 σ = 4’.2± 0’.5 G21.5-0.9 Chandra XMM-Newton HESS J1616-508 σ = 0’.91 ± 0’.05 σ = 1’.8 ± 0’.5
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.
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) http://www.mpp.mpg.de/~rwagner/sources/
Multi-frequency studies of Blazars Blazar sequence Radio Optical X-ray GeV TeV Flat Spectrum Radio Quasars (= FSRQ, e.g. PKS0528-134) 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., 0716+714) High-frequency peaked BL Lac (= HBL e.g., Mrk421) Low-energy peak (Synchrotron) High-energy peak (Inverse Compton) LE HE Kataoka 02 Kubo+ 98
High power jets : Luminous FSRQ PKS 2149-306 Fermi LAT LX > 2x1047 erg/sec (>109 Msolar SMBH) HXI 100ks The best-fit synchrotron-Compton model for PKS 2149-306. 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
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
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.