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

Crs production and propagation historyCharged nuclei - isotopes - antinuclei

Moskalenko, Strong & Reimer astro-ph/0402243

1. 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

3. Solar Modulation

* Force field approximation? * Charge-dependent models?

Acceleration of GCRs: SNRs

SNR RX J0852.0-4622 Observed in X-ray & -rays

(Hess Coll. A&A 2005)

If all from hadronic sources IS acceleration spectrum

BUT: how much is IC?

(E) E- =2.10.1

Predictions of supernova shock acceleration: (E) E- = 2.0-2.1 (Berezhko & Ellison 1999, Baring et al. 1998)

Complex SNR CTB 37 Observed in X-ray & -rays

(Hess Coll. arXiv:0803.0702)

Hadron dominated scenariomore likely

Determination of acceleration spectrum

Ellison, Patnaude, Slane, Blasi, Gabici ApJ 2007

Gabici & Aharonian ApJL 2007

Proton induced -rays- from SNR (top)

- from a cloud at 100 pc from SNR (1,2,3,4: different explosion times)

IC and -decay Emission

20 MeV – 300 GeV explorable by GLASTshould allow a discrimination between

hadronic and leptonic emissions

Transport equation in diffusion models

DiffusionConvection Destruction on ISM

CR sources: primaries, secondaries (spallations)

Reacceleration

Ionization, Coulomb, Adiabatic,Reacceleration

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

Diffusive modelsJopikii & Parker 1970; Ptuskin & Ginzburg, 1976; Ginzburg, Khazan & Ptuskin 1980; Weber, Lee & Gupta 1992, ....

Some recently developped diffusive models:

1. Maurin, FD, Taillet, Salati ApJ 2001; Maurin, Taillet, FD A&A 20022. Strong & Moskalenko ApJ 1998; Moskalenko, Strong, Ormes, Potgieter, ApJ 2002 3. Shibata, Hareyama, Nakazawa, Saito ApJ 2004; 20064. Jones, Lukasiak, Ptuskin, Webber ApJ 2001 (Modified Weighted-slab technique)5. 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 includedshapes the model

2-zone Semi-analytic Diffusive ModelMaurin, FD, Taillet, Salati ApJ 2001; Maurin, Taillet, FD A&A 2002

• Diffusion coefficient K(R)=K0R

• Convective velocity Vc

• Alfven velocity VA

• Diffusive halo thickness L• Acceleration spectrum Q(E)=p

K0, , Vc, VA, L, ()

+All the effects included (VA0 & VC0)

+2D semi-analytic

+ Local Bubble for radioactives

- ISM constant

-VC constant througout the halo

- VA in the disk

Systematic scan of parameter space

Evaluation of uncertainties

Results on Observed Prim/SecMaurin, FD, Taillet, Salati, ApJ (2001) Maurin, Taillet, FD A&A (2002)

Systematic scan of the parameter space6 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 spectrum α~2.0

No need for breaks in K(E) or Q(E)

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

Results on protons and antiprotons

Conventional (solid) Optimized (dots)

Models tuned forGamma rays

But new FERMI data…

Strong, Moskalenko, Reimer ApJ 2004

More results on radioactives,absolute fluxes,

electronsand positron, ....

Results from Jones et al. ApJ 2001

Modified weighted slab technique applied to different models Fits to secondary/primary

Simplified modelsNo reacceleration + convectionGood fit to B/C (C, Fe)High diffusion power spectraHigh accel. spectra (2.35-2.40)Break (at non-rel. E, reacc. only)

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

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?

Antiprotons data

Demodulated data cover ~ 0.7 ÷40 GeV All experiments from ballons (residual atmosphere) except AMS98

Pamela preliminary data: compatible with these secondaries

Secondary CR production

FD, Maurin, Brun, Delahaye, Salati PRL 2009

Antiproton/proton: data and models

Small uncertainties – excellent fit to data – consistencyNO need for new phenomena (astrophysics/particle

physics)

Donato et al. PRL 2009

Predictions with the same semi-analytical DM as for positrons(and B/C, radioactive isotopes)

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}

More astrophysical clues with antiprotons

Re-acceleration in mature SNRs –

High energy preliminary Pamela data do not show increasing flux

Blasi & Serpico arxiv:0904.0871

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

Limits get weaker for increasing masses

Boost < 6-20-40 for m=0.1-0.5-1 TeV

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?

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

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

Positron/electron: data and predictionsDelahaye et al. A&A 2009

Yellow band: secondary positrons & propagation uncertainties

Hard electrons: γ=3.34

There is no “standard” flux – dashed is B/C best fit

Stro

ngly d

isfav

oure

d by

Ferm

i and

pre

lim. P

amela

FERMI Electrons and PAMELA positron fraction

Models adjusted on Fermi e-, breaks at 4 GeV (acceleration)No Klein-Nishina losses

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-)

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!