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Cosmic ray propagation models and interpretation of results from recent space experiments

Cosmic ray propagation models and interpretation of results from recent space experiments. Fiorenza Donato Department of Theoretical Physics, Un. Torino Marcel Grossman Meeting – Session AP3 Paris, july 17, 2009.

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Cosmic ray propagation models and interpretation of results from recent space experiments

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  1. Cosmic ray propagation models and interpretation of results from recent space experiments Fiorenza Donato Department of Theoretical Physics, Un. Torino Marcel Grossman Meeting – Session AP3 Paris, july 17, 2009

  2. Crs production and propagation historyCharged nuclei - isotopes - antinuclei • Synthesis and acceleration • * Are SNR the accelerators? • * How are SNR distributed? • * What is the abundance at sources? • * Are there exotic sources out of the disc? 2. Transport in the Milky Way * Diffusion by galactict B inhom. * Interaction with the ISM: - destruction - spallation production of secondaries * electromagnetic losses - ionization on neutral ISM - Coulomb on ionized plasma * Convection * Reacceleration Moskalenko, Strong & Reimer astro-ph/0402243 3. Solar Modulation * Force field approximation? * Charge-dependent models?

  3. Predictions of supernova shock acceleration: (E)  E- = 2.0-2.1 (Berezhko & Ellison 1999, Baring et al. 1998) Acceleration of GCRs: SNRs SNR RX J0852.0-4622 Observed in X-ray & -rays  (Hess Coll. A&A 2005) (E)  E- =2.10.1  If all from hadronic sources   IS acceleration spectrum BUT: how much is IC? Complex SNR CTB 37 Observed in X-ray & -rays (Hess Coll. arXiv:0803.0702) Hadron dominated scenario more likely

  4. Determination of acceleration spectrum Gabici & Aharonian ApJL 2007 IC and -decay Emission 20 MeV – 300 GeV explorable by GLAST should allow a discrimination between hadronic and leptonic emissions Ellison, Patnaude, Slane, Blasi, Gabici ApJ 2007 • Proton induced -rays • - from SNR (top) • from a cloud at 100 pc from SNR • (1,2,3,4: different explosion times)

  5. Transport equation in diffusion models Convection Destruction on ISM Diffusion CR sources: primaries, secondaries (spallations) Reacceleration Ionization, Coulomb, Adiabatic, Reacceleration

  6. Characteristic times for various processes The smaller the time, the most effective the process is For protons: escape dominates > 1 GeV For E<1 GeV, convection and e.m. losses. For iron: Spallations dominate for E<10 GeV/n Spatial origin of primary CRs Taillet & Maurin A&A 2003

  7. Diffusive modelsJopikii & Parker 1970; Ptuskin & Ginzburg, 1976; Ginzburg, Khazan & Ptuskin 1980; Weber, Lee & Gupta 1992, .... • Some recently developped diffusive models: • Maurin, FD, Taillet, Salati ApJ 2001; Maurin, Taillet, FD A&A 2002 • Strong & Moskalenko ApJ 1998; Moskalenko, Strong, Ormes, Potgieter, ApJ 2002 • Shibata, Hareyama, Nakazawa, Saito ApJ 2004; 2006 • Jones, Lukasiak, Ptuskin, Webber ApJ 2001 (Modified Weighted-slab technique) • Evoli, Gaggero, Grasso, Maccione JCAP 2008 (only at HE) • Ingredients: • - Geometry of the galaxy • Distribution of the sources • Acceleration spectrum • Distribution and composition of ISM • Diffusion coefficient • Electromagnetic energy losses • Destruction cross sections • Production cross sections • Radioactive isotopes • Convection • Reacceleration • ........ IF and HOW these elements are included shapes the model

  8. 2-zone Semi-analytic Diffusive Model Maurin, FD, Taillet, Salati ApJ 2001; Maurin, Taillet, FD A&A 2002 • +All the effects included (VA0 & VC0) • +2D semi-analytic • + Local Bubble for radioactives • - ISM constant • VC constant througout the halo • VA in the disk • Diffusion coefficient K(R)=K0bRd • Convective velocity Vc • Alfven velocity VA • Diffusive halo thickness L • Acceleration spectrum Q(E)=pa • K0, d, Vc, VA, L, (a) Systematic scan of parameter space Evaluation of uncertainties

  9. Results on Observed Prim/SecMaurin, FD, Taillet, Salati, ApJ (2001) Maurin, Taillet, FD A&A (2002) Systematic scan of the parameter space 6 free parameters: diffusion (K0,), convection (VC), acceleration(α), reacceleration (VA), diffusive halo (L) Only model WITH convection AND reacceleration Kolmogorov (δ=0.3) spectrum disfavoured, δ ~ 0.6-0.7, K0 ~ 0.003-0.1 kpc2/Myr Acceleration spectrumα~2.0 No need for breaks in K(E) or Q(E)

  10. Diffusive model in Galprop Strong & Moskalenko ApJ 1998; Moskalenko, Strong, Ormes, Potgieter, ApJ 2002 + All the effects included + Full 3D – numerical approach + Distribution of gas and sources Diff+Conv =0.60 (0 if R<4GV) =2.46/2.16 Diff+Reacc =0.33, =0.43 Qualitative (not quantitative) fits Breaks in spectra and K(E) Convection + reacceleration: not best fit

  11. Results on protons and antiprotons Strong, Moskalenko, Reimer ApJ 2004 Conventional (solid) Optimized (dots) Models tuned for Gamma rays But new FERMI data… More results on radioactives, absolute fluxes, electrons and positron, ....

  12. Results from Jones et al. ApJ 2001 Modified weighted slab technique applied to different models Fits to secondary/primary Simplified models No reacceleration + convection Good fit to B/C (C, Fe) High diffusion power spectra High accel. spectra (2.35-2.40) Break (at non-rel. E, reacc. only)

  13. Results from Shibata, Hareyama, Nakazawa, Saito, APJ 2004; 2006 Fully 3D analytical model with reacceleration and losses (no ion.), no boundaries, simple exponential forms for distributions, no convection Qualitative agreement with data

  14. No definite propagation model comes out High degeneracy of models Need more data around 1 GeV/n and at >20-30 GeV/n What consequences on antimatter fluxes?

  15. Antiprotons data FD, Maurin, Brun, Delahaye, Salati PRL 2009 Secondary CR production Demodulated data cover ~ 0.7 ÷40 GeV All experiments from ballons (residual atmosphere) except AMS98 Pamela preliminary data: compatible with these secondaries

  16. Antiproton/proton: data and models Predictions with the same semi-analytical DM as for positrons (and B/C, radioactive isotopes) Donato et al. PRL 2009 PROTON flux: Φ=Aβ-P1R-P2 • T<20 GeV: Bess 1997-2002 (Shikaze et al. Astropart. Phys. 2007) • T>20 GeV, our fit (Bess98, BessTeV&AMS): {24132; 0; 2.84} Small uncertainties – excellent fit to data – consistency NO need for new phenomena (astrophysics/particle physics)

  17. More astrophysical clues with antiprotons Blasi & Serpico arxiv:0904.0871 Re-acceleration in mature SNRs – High energy preliminary Pamela data do not show increasing flux

  18. Allowed Enhancement factors for DARK MATTERcontribution in antiproton data Limits obtained for: • <σv>=3·10-26 cm3/s • MED prop parameters • Cored Isoth DM • ρ=0.3 GeV/cm3 • 2σ error bars, T>10 GeV Boost < 6-20-40 for m=0.1-0.5-1 TeV Limits get weaker for increasing masses

  19. Enhancement of the antiproton flux? • Clumpiness in the DM distribution in the Milky Way: energy dependent(Lavalle, Yaun, Maurin, Bi A&A 2008)  boost factors may be different for positrons, antiprotons, gamma rays, …(Lavalle, Pochon, Salati, Taillet A&A 2006) • a low boost factor (for gamma rays) emerges from most recent N-body simulations (Diemand et al. 2008; Springel et. MNRAS 2008; Brun, Delahaye, Diemand, Profumo, Salati 0904.0812) • Enhancement of the annihilation cross section (Bergstrom PLB 1989; Hisano et al. PRL 2004)  depends on the mass (> TeV) Compatibility with positron data?

  20. Propagation of secondary positronsDelahaye, Lavalle, Lineros, FD, Fornengo, Salati, Taillet A&A 2009 Diffusive semi-analytical model: Thin disk and confinement halo Free parameters fixed by B/C Above few GeV: only spatial diffusion and energy losses Energetic positrons are quite local

  21. Positron flux: data and predictions Same propagation models as for B/C(Maurin, FD, Salati, Taillet ApJ 2001) Positron flux well described by secondary contribution Uncertainties due to propagation

  22. Positron/electron: data and predictions Delahaye et al. A&A 2009 Strongly disfavoured by Fermi and prelim. Pamela Yellow band: secondary positrons & propagation uncertainties Hard electrons: γ=3.34 There is no “standard” flux – dashed is B/C best fit

  23. FERMI Electrons and PAMELA positron fraction Models adjusted on Fermi e-, breaks at 4 GeV (acceleration) No Klein-Nishina losses

  24. FERMI Electrons and PAMELA positron fraction:contribution from local pulsars (d<3 kpc)(Grasso et. Al 0905.0636) Excellent description of both e- and e+/(e+e-)

  25. Conclusions and perspectives • Diffusive models with reacceleration/convection reproduce data for many species without too many adjustements • A definite model does not come out – degeneracies and uncertainties • Antimatter in CRs and particle DM in the galaxy: strong connection! Mostly limited by propagation uncertainties, astrophysical backgrounds, data • Data from different species: nuclei, isotopes (rad., K), electrons and positrons, antiprotons, gamma-rays, on a large energetic range, are needed • Many crucial experimental breakthroughs are just around the corner!

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