galactic diffuse gamma-ray emission
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Galactic Diffuse Gamma-Ray EmissionGLAST Japan Workshop
November 24-25, 2006
Tuneyoshi KAMAE (SLAC/KIPAC, Stanford University)
1. Introduction:• Status of EGRET γ-ray diffuse emission mdeling• What Integral see in hard X-ray band• Diffuse emission seen in the X-ray band
2. New anaysis technologies for GLAST era we are working on• Correct p-p int. modeling for secondary particles (pub and to be pub)• Correct analysis of low-energy EGRET diffuse emission (to be pub) • 3D ISM distr. by Nakanishi and Sofue for H2 and HI (pub and to be pub)• Modeling of non-Fermi acceleration senario (in progress)
3. Preliminary results• Possible new interpretation of EGRET γ-ray diffuse emission (in progress)• Clarification of “unidentified sources”: Suzaku, Nanten, GLAST, NuStar
Cosmic Ray Propagation and Interaction- Interplay among sources(SNRs), propagation, targets(H2,HI, ISRF) -
From Strong and Moskalenko
GALPROP: γ-Ray Spectrum- A parameter set to explain EGRET γ-ray spectrum -
IC: uncertainty in •e−/e+
•ISRF
e−/e+: •2-3 time the local flux•spectral shape adjusted
π0: proton flux•~2 times higher than LIS
GALPROP: Longitude Distribution- Optimized to explain EGRET γ-ray map -
30-50MeV 50-70MeV 70-100MeV
100-150MeV 150-300MeV 500-1000MeV
Glon distribution for |Glat|<5.5 deg Look all similar: tracer for H2 and HI?
GALPROP: Latitude Distribution- Optimized to explain EGRET γ-ray map -
30-50MeV 50-70MeV 70-100MeV
100-150MeV 150-300MeV 500-1000MeV
Glat distribution for |Glon|<30.5 deg Look all similar: tracer for H2 and HI?
Observation in Hard X-ray Band- Ginga, ASCA, Integral, Suzaku -
Exposure map of Integral Has not survey the entire ridge
Observation in Hard X-ray Band- Integral -
Enhancement in |Glon|<10 deg
Deconvolution of EGRET’s PSF- Why essential -
True directionof γ-ray
Reconstructed direction of γ-ray
Angular dependence of “exposure” (~FOV)
True exposure
Assumed exposure
EGRET PSF for E<150MeV
EGRET FOV
High latitude flux is systematically over estimated by up to 20-30%
Need sharper image for detailed analyses
Kamae, in prep
Deconvolution of EGRET PSF- PSF Representation on Glon-Glat Map is Glat-dependent -
Index2.2 at Glat=0.0
Index2.2 at Glat=+/-22.0 Index2.2 at Glat=+/-26.0
Angular Response Matrix Based on EgretPsf- Building 3600x3600 Matrix for E0-E9-
Deconvolution of EGRET’s PSF- Ideal and Poisson noise dominated cases -
True Latitude Distribution in Low Energy- PSF deconvolved maps –
l=-74~-34 l=-30~-30 l=34~-74
E(MeV)=30-50(brn), 50-70(mgt), 70-100(grn), 100-150(blu), 150-300(blk)
Proton-Proton Interaction Modeling- Cross-sections -
Total cross-section
Total inelastic
Non-diffractive
Diffractive process
Elastic cross-section
Delta(1232) excitation
Reson(1600) excitation Kamae, Abe, Koi (ApJ 05)Kamae, Karlsson, Mizuno, Koi, Abe (to be submitted to ApJ)
Proton-Proton Interaction Modeling- Low energy cross-sections -
Total inelastic
Non-diffractive
Diffractive process
Delta(1232) excitationReson(1600) excitation
Experimental data on total inelastic
Model vs Exp. Data- Resonance region -
Tp=0.65GeV Tp=0.68GeV Tp=2.0GeV
Model vs Exp. Data- Pi-0 multiplicity -
Total inelastic
Non-diffractive
Diffractive process
Delta(1232)Reson(1600)
Experimental data
Predictions of Our Paramerized Model- Harder secondary spctr expected -
γ-ray spectrum will be harder than that of the incident proton
Galprop withbuilt-in pp model
Galprop withour pp model
γ-ray spectrumindex=1.95
γ-ray spectrum for power-law proton of index=2.0
Kamae, Abe, Koi (ApJ 05)Kamae, Karlsson, Mizuno, Koi, Abe (to be submitted to ApJ)
Predictions of Our Param. Model- Secondaries positron dominates over electrons -
Positron
Electron
Spectrum vs. Viewing Angle- Important for mom-dependent diffusion -
Spiral arm structure we now know is different from that by Georgelin & Georgelin ‘79
Perseus
Local
Sagittarius-C
arina
Norma
Scutum-Crux
HI cloud and armsNakanishi & Sofue ‘05
H2 cloud and armsNakanishi & Sofue ‘05
Bar structure
Density too high?
Matter Distribution in 3D- H2 and HI 3D distr. by Nakanishi and Sofue -
Matter Distribution- H2 and HI projected column density -
Matter Distribution- H2 and HI in the Galactic disk (|Glat|<4deg) -
H2+HI
H2
HI
Correction for missing section
Correction for missing section
Something wrong?
EGRET Intensity Profile along Gal Long. (1/4)
EGRET Intensity Profile along Gal Long. (2/4)
EGRET Intensity Profile along Gal Long. (3/4)
EGRET Intensity Profile along Gal Long. (4/4)
Acceleration at SNR and Galactic CR Spectrum
Berezhko &Elliison 1999
Not power law spectrum at the shockNaïve calculation by Yamasaki (‘97)
Heating and instabilitybuild-up
Run-away turbulanceδB/B >> 1
Acceleration(Non Fermi-type?)
Mom. dependent escape
Conclusion
• New tools and new modeling bring up new physics.• Multiwavelengthe collaboration is norm. From Japnese
perspective:üGLASTüSuzaku (hard X-ray)üNanten and its upgrade (molecular clouds)üSubaru and smaller telescopes (GRB followup)üCangaroo (TeV γ-ray)
• Resolution of diffuse Galactic emission and origin of CR• Understanding acceleration mech. and discovery (or
upper limit) of dark-matter will follow
Ec=5GeV
E-2.7
E-3.7
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