Challenges in Astrophysics of CR (knee--) & γ-rays Igor V. Moskalenko (Stanford) Ø Ø Intro to the relevant physics Some of the challenges… Modeling of the CR propagation and diffuse emission Perspectives: Pamela, GLAST and other near future missions
CR Interactions in the Interstellar Medium SNR RX J 1713 -3946 X, γ e PSF HESS Preliminary ISM tron + - B P diffusion He energy losses CNO reacceleration + convection e etc. π + ro synch Chandra IC ISRF s brems gas π0 GLAST gas _ P + π- p Li. Be. B He CNO + e- Flux 42 sigma (2003+2004 data) 20 Ge. V/n BESS PAMELA Igor V. Moskalenko 2 AMS helio-modulation December 12, 2005 ACE CR species: Ø Only 1 location Ø modulation TA-seminar/Fermilab
Elemental Abundances: CR vs. Solar System CR abundances: ACE O Si Na Fe S CNO Al Cl Li. Be. B Cr. Mn F Sc. Ti. V Solar system abundances Long propagation history… Igor V. Moskalenko 3 December 12, 2005 TA-seminar/Fermilab
Nuclear component in CR: What we can learn? Stable secondaries: Li, Be, B, Sc, Ti, V Propagation parameters: Radio (t 1/2~1 Myr): Diffusion coeff. , halo size, Alfvén speed, 10 Be, 26 Al, 36 Cl, 54 Mn convection velosity… K-capture: 37 Ar, 49 V, 51 Cr, 55 Fe, 57 Co Energy markers: Reacceleration, solar modulation Short t 1/2 radio 14 C & heavy Z>30 Heavy Z>30: Cu, Zn, Ga, Ge, Rb Igor V. Moskalenko 4 Local medium: Local Bubble Material & acceleration sites, nucleosynthesis (rvs. s-processes) December 12, 2005 o. Nuclesis: e synthnovae, superniverse, u early Bang… Big Dark M -, atter (p đ, e + , γ) Diffuse γ-rays Galactic, extragalactic: blazars, relic neutralino Solar on lati modu TA-seminar/Fermilab
Diffuse Galactic Gamma-ray Emission ~80% of total Milky Way luminosity at HE !!! Tracer of CR (p, e−) interactions in the ISM (π0, IC, bremss): o o Study of CR species in distant locations (spectra & intensities) Ø CR acceleration (SNRs, pulsars etc. ) and propagation Emission from local clouds → local CR spectra Ø CR variations, Solar modulation May contain signatures of exotic physics (dark matter etc. ) Ø Cosmology, SUSY, hints for accelerator experiments Background for point sources (positions, low latitude sources…) Besides: o “Diffuse” emission from other normal galaxies (M 31, LMC, SMC) Ø Cosmic rays in other galaxies ! o Foreground in studies of the extragalactic diffuse emission o Extragalactic diffuse emission (blazars ? ) may contain signatures of exotic physics (dark matter, BH evaporation etc. ) Calculation requires knowledge of CR (p, e) spectra in the entire Galaxy Igor V. Moskalenko 5 December 12, 2005 TA-seminar/Fermilab
Transport Equations ~90 (no. of CR species) sources (SNR, nuclear reactions…) diffusion convection diffusive reacceleration (Galactic wind) (diffusion in the momentum space) E-loss radioactive decay fragmentation + boundary conditions Igor V. Moskalenko 6 December 12, 2005 ψ(r, p, t) – density per total momentum TA-seminar/Fermilab
CR Propagation: Milky Way Galaxy 1 kpc ~ 3 x 1018 cm pc Optical image: Cheng et al. 1992, Brinkman et al. 1993 Radio contours: Condon et al. 1998 AJ 115, 1693 10 0 NGC 891 Halo 0. 1 -0. 01/ccm 40 kp c Ga 1 - s, 10 so 0/ urc cc es m Halo 4 - 12 kp c Sun R Band image of NGC 891 1. 4 GHz continuum (NVSS), 1, 2, … 64 m. Jy/ beam Igor V. Moskalenko 7 Intergalactic space December 12, 2005 “Flat halo” model (Ginzburg & Ptuskin 1976) TA-seminar/Fermilab
A Model of CR Propagation in the Galaxy Ø Gas distribution (energy losses, π0, brems) Ø Interstellar radiation field (IC, e± energy losses) Ø Nuclear & particle production cross sections Ø Gamma-ray production: brems, IC, π0 Ø Energy losses: ionization, Coulomb, brems, IC, synch Ø Solve transport equations for all CR species Ø Fix propagation parameters Ø “Precise” Astrophysics Igor V. Moskalenko 8 December 12, 2005 TA-seminar/Fermilab
How It Works: Fixing Propagation Parameters E 2 Flux Carbon Radioactive isotopes: Galactic halo size Zh Ek, Ge. V/nucleon In te r st e lla r B/C Be 10/Be 9 Ek, Me. V/nucleon Using secondary/primary nuclei ratio & flux: • Diffusion coefficient and its index • Propagation mode and its parameters (e. g. , reacceleration VA, convection Vz) Zh increase Ek, Me. V/nucleon Igor V. Moskalenko 9 December 12, 2005 TA-seminar/Fermilab
Peak in the Secondary/Primary Ratio • Leaky-box model: fitting path-length distribution -> free function • Diffusion models: Ø Diffusive reacceleration Ø Convection Ø Damping of interstellar turbulence Ø Etc. B/C Ek, Me. V/nucleon too sharp max? Igor V. Moskalenko 10 Accurate measurements in a wide energy range may help to distinguish between the models December 12, 2005 TA-seminar/Fermilab
Distributed Stochastic Reacceleration Simon et al. 1986 Seo & Ptuskin 1994 Scattering on magnetic turbulences Dpp~ p 2 Va 2/D D ~ v. R 1/3 - Kolmogorov spectrum Icr B 1/3 ΔE Fermi 2 -nd order mechanism Dxx = 5. 2 x 1028 (R/3 GV)1/3 cm-2 s-1 Va = 36 km s-1 γ ~ R-δ, δ=1. 8/2. 4 below/above 4 GV Igor V. Moskalenko 11 December 12, 2005 strong reacceleration weak reacceleration E TA-seminar/Fermilab
Convection Galactic wind Jones 1979 Escape length Xe v wind or turbulent diffusion D~R 0. 6 R-0. 6 resonant diffusion E problem: too broad sec/prim peak Dxx = 2. 5 x 1028 (R/4 GV)0. 6 cm-2 s-1 d. V/dz = 10 km s-1 kpc-1 γ ~ R-δ, δ=2. 46/2. 16 below/above 20 GV Igor V. Moskalenko 12 December 12, 2005 TA-seminar/Fermilab
Damping of Interstellar Turbulence Kolmogorov cascade: Iroshnikov-Kraichnan cascade: nonlinear cascade W(k) Simplified case: dissipation 1/1020 cm 1/1012 cm • • Mean free path 1 -D diffusion No energy losses k Ptuskin et al. 2003, 2005 Igor V. Moskalenko 13 December 12, 2005 TA-seminar/Fermilab
Li. Be. B: Major Production Channels Propagated Abundance * Cross-section Li 6 C 12 Li Be A= 7 9 O 16 B 10 N 13 11 14 15 • Well defined (65%): C 12, O 16 ->Li. Be. B N 14 -> Be 7 (see Moskalenko & Mashnik 28 ICRC, 2003) • Few measurements: C 13, N -> Li. Be. B B -> Be. B • Unknown: Li. Be. B, C 13, N -> Li. Be. B Ø“Tertiary” reactions also important! -35% Igor V. Moskalenko 14 December 12, 2005 TA-seminar/Fermilab
Effect of Cross Sections: Radioactive Secondaries Different size from different ratios… 27 Al+p 26 Al T 1/2=? W ST ST nat. Si+p 26 Al W Zhalo, kpc Ek, Me. V/nucleon Igor V. Moskalenko 15 • Errors in CR measurements (HE & LE) • Errors in production cross sections • Errors in the lifetime estimates • Different origin of elements (Local Bubble ? ) December 12, 2005 TA-seminar/Fermilab
Wherever you look, the Ge. V -ray excess is there ! EGRET data Excess: x 2 4 a-f Igor V. Moskalenko 16 December 12, 2005 TA-seminar/Fermilab
Reacceleration Model vs. Plain Diffusion Antiproton flux B/C ratio Plain Diffusion (Dxx~β-3 R 0. 6) B/C ratio Antiproton flux Diffusive Reacceleration Excess: x 2 Igor V. Moskalenko 17 December 12, 2005 TA-seminar/Fermilab
Positron Excess ? HEAT (Beatty et al. 2004) e+/e E > 6 Ge. V GALPROP HEAT 2000 HEAT 1994 -95 10 1 Excess: 20% HEAT combined 1 E, Ge. V 10 GALPROP E, Ge. V Q: Are all the excesses connected? A: “Yes” and “No” Systematic errors of different detectors Same progenitor (CR p or DM) for pbars, e+’s, γ’s Igor V. Moskalenko 18 December 12, 2005 TA-seminar/Fermilab
CR Source Distribution CR after propagation SNR source Lorimer 2004 Pulsars diffuse γ-ray distribution The CR source (SNRs, pulsars) distribution is too narrow to match the CR distribution in the Galaxy assuming XCO=N(H 2)/WCO=const (CO is a tracer of H 2) Igor V. Moskalenko 19 December 12, 2005 TA-seminar/Fermilab
CR Abundances at LE & HE (ACE vs HEAO-3) Fitting to measured CR abundances in the wide energy range (~0. 1 – 30 Ge. V) is problematic. Fit quality Relat. deviation May indicate: • systematic or crosscalibration errors • different origin of LE and HE CR =(Calcs-Exp)/Exp Igor V. Moskalenko 20 December 12, 2005 TA-seminar/Fermilab
Hypotheses… Provide good agreement with all data (diffuse gammas, pbars, e+) Ø CR intensity variations Ø Dark Matter signals Other possibilities: Harder CR spectrum (protons, electrons) – deviates limits from pbars, gamma-ray profiles Influence of the Local Bubble (local component) – helps with pbars, but doesn’t help with diffuse gammas Igor V. Moskalenko 21 December 12, 2005 TA-seminar/Fermilab
Diffuse emission models Dark Matter EGRET “Ge. V Excess” from Hunter et al. Ap. J (1997) from Strong et al. Ap. J (2004) from de Boer et al. A&A (2005) >0. 5 Ge. V Igor V. Moskalenko 22 Cosmic Ray Spectral Variations There are two possible BUT fundamentally different explanations of the excess, in terms of exotic and traditional physics: Ø Dark Matter Ø CR spectral variations Both have their pros & cons. December 12, 2005 0. 5 -1 Ge. V TA-seminar/Fermilab
More frequent SN in the spiral arms sun SNR number density CR Variations in Space & Time R, kpc Electron/positron energy losses Igor V. Moskalenko 23 Historical variations of CR intensity: ~40 kyr (10 Be in South Polar ice), ~2. 8 Myr (60 Fe in deep sea Fe. Mn crust) Konstantinov et al. 1990 Different “collecting” areas A vs. p (σ~30 mb) (different sources ? ) December 12, 2005 TA-seminar/Fermilab
Electron Fluctuations/SNR stochastic events Ge. V electrons 100 Te. V electrons E(d. E/dt)-1, yr GALPROP/Credit S. Swordy 107 yr 106 yr Electron energy loss timescale: 1 Te. V: ~300 kyr 100 Te. V: ~3 kyr Energy losses Bremsstrahlung Ionization IC, synchrotron Coulomb 1 Ge. V 1 Te. V Ekin, Ge. V Igor V. Moskalenko 24 December 12, 2005 TA-seminar/Fermilab
Ge. V excess: Optimized/Reaccleration model Uses all sky and antiprotons & gammas to fix the nucleon and electron spectra Ø Uses antiprotons to fix the intensity of CR nucleons @ HE Ø Uses gammas to adjust q the nucleon spectrum at LE q the intensity of the CR electrons (uses also synchrotron index) antiprotons ü pbars ü e+ -flux ü γ-rays Ø Uses EGRET data up to 100 Ge. V electrons Ek, Ge. V protons x 4 x 1. 8 Ek, Ge. V Igor V. Moskalenko 25 Ek, Ge. V December 12, 2005 TA-seminar/Fermilab
Secondary e± are seen in γ-rays ! Lots of new effects ! electrons Heliosphere: e+/e~0. 2 sec. IC positrons brems Improves an agreement at LE Igor V. Moskalenko 26 December 12, 2005 TA-seminar/Fermilab
Diffuse Gammas at Different Sky Regions Hunter et al. region: l=300°-60°, |b|<10° Inner Galaxy: l=330°-30°, |b|<5° Outer Galaxy: l=90°-270°, |b|<10° corrected l=40°-100°, |b|<5° Intermediate latitudes: l=0°-360°, 10°<|b|<20° Intermediate latitudes: l=0°-360°, 20°<|b|<60° Milagro Igor V. Moskalenko 27 December 12, 2005 TA-seminar/Fermilab
Longitude Profiles |b|<5° 50 -70 Me. V 2 -4 Ge. V Igor V. Moskalenko 28 December 12, 2005 0. 5 -1 Ge. V 4 -10 Ge. V TA-seminar/Fermilab
Latitude Profiles: Inner Galaxy 0. 5 -1 Ge. V 50 -70 Me. V 4 -10 Ge. V Igor V. Moskalenko 29 December 12, 2005 2 -4 Ge. V 20 -50 Ge. V TA-seminar/Fermilab
Latitude Profiles: Outer Galaxy 50 -70 Me. V 2 -4 Ge. V Igor V. Moskalenko 30 December 12, 2005 0. 5 -1 Ge. V 4 -10 Ge. V TA-seminar/Fermilab
Anisotropic Inverse Compton Scattering Ø Electrons in the halo see anisotropic radiation Ø Observer sees mostly head-on collisions Energy density e- R=4 kpc small boost & less collisions γ γ head-on: large boost & more collisions Z, kpc γ Important @ high latitudes ! Igor V. Moskalenko 31 e- sun December 12, 2005 TA-seminar/Fermilab
Extragalactic Gamma-Ray Background E 2 x. F Predicted vs. observed EGRB in different directions Sreekumar et al. 1998 Elsaesser & Mannheim, astro-ph/0405235 Strong et al. 2004 E, Me. V • Blazars • Cosmological neutralinos Igor V. Moskalenko 32 December 12, 2005 TA-seminar/Fermilab
Distribution of CR Sources & Gradient in the CO/H 2 Pulsar distribution Lorimer 2004 CR distribution from diffuse gammas (Strong & Mattox 1996) SNR distribution (Case & Bhattacharya 1998) sun XCO=N(H 2)/WCO: Histo –This work, Strong et al. ’ 04 -----Sodroski et al. ’ 95, ’ 97 1. 9 x 1020 -Strong & Mattox’ 96 –Boselli et al. ’ 02 ~Z-1 ~Z-2. 5 -Israel’ 97, ’ 00, [O/H]=0. 04, 0. 07 dex/kpc Igor V. Moskalenko 33 December 12, 2005 TA-seminar/Fermilab
Again Diffuse Galactic Gamma Rays Very good agreement ! More IC in the GC – better agreement ! 2 -4 Ge. V The pulsar distribution vs. R falls too fast OR larger H 2/CO gradient Igor V. Moskalenko 34 December 12, 2005 TA-seminar/Fermilab
Igor V. Moskalenko 35 December E. Bloom’ 05 12, 2005 TA-seminar/Fermilab
Matter, Dark Energy… Ω ≡ ρ/ρcrit Ωtot =1. 02 ΩMatter =4. 4% ΩDM =23% ΩVacuum =73% +/− 0. 02 +/− 0. 4% +/− 4% SUSY DM candidate has also other reasons to exist -particle physics… “Supersymmetry is a mathematically beautiful theory, and would give rise to a very predictive scenario, if it is not broken in an unknown way which unfortunately introduces a large number of unknown parameters…” Lars Bergström (2000) Igor V. Moskalenko 36 December 12, 2005 TA-seminar/Fermilab
Where is the DM ? ! Ø Ø ü What (flavors): Neutrinos ~ visible matter Super-heavy relics: “wimpzillas” Axions Topological objects “Q-balls” Neutralino-like, KK-like Where (places): ü Galactic halo, Galactic center v The sun and the Earth How (tools): q Direct searches – low-background experiments (DAMA, EDELWEISS) – neutrino detectors (AMANDA/Ice. CUBE) – Accelerators (LHC) ü Indirect searches – CR, γ’s (PAMELA, GLAST, BESS) from E. Bloom presentation Igor V. Moskalenko 37 December 12, 2005 TA-seminar/Fermilab
Example “Global Fit: ” diffuse γ’s, pbars, positrons GALPROP/W. de Boer et al. hep-ph/0309029 Supersymmetry: Ø Ø Ø MSSM (Dark. SUSY) Lightest neutralino χ0 mχ ≈ 50 -500 Ge. V S=½ Majorana particles χ0χ0−> p, pbar, e+, e−, γ γ pbars Ø Look at the combined (pbar, e+, γ) data Ø Possibility of a successful “global fit” can not be excluded -non-trivial ! Igor V. Moskalenko 38 December 12, 2005 e+ TA-seminar/Fermilab
Longitude and Latitude Distr. E >0. 5 Ge. V Out of the plane (± 300 in long. . ) In the plane (± 50 in lat. ) Igor V. Moskalenko 39 December 12, 2005 TA-seminar/Fermilab
Executive Summary –de Boer et al. astro-ph/0408272 Observed Profile: Expected Profile (NFW) z EGRET data + GALPROP xy xy Isothermal Profile v 2 M/r=cons. and xz M/r 3 1/r 2 for const. rotation curve xz Rotation Curve x y DM halo 2003, Ibata et al, Yanny et al. disk bulge Inner Ring Outer Ring Halo profile Igor V. Moskalenko 40 December 12, 2005 TA-seminar/Fermilab
PAMELA: Secondary to Primary ratios Ø LE: sec/prim peak: one instrument -no cross calibration errors Ø HE: Dxx(R) plots: M. Simon Page Number
PAMELA positrons After 3 years Ø A factor of 2 will become statistically significant Ø Measuring absolute flux not ratio Ø Solar minimum conditions Igor V. Moskalenko 42 December 12, 2005 TA-seminar/Fermilab
PAMELA antiprotons After 3 years Igor V. Moskalenko 43 December 12, 2005 TA-seminar/Fermilab
Igor V. Moskalenko 44 December 12, 2005 TA-seminar/Fermilab
A. Morselli Igor V. Moskalenko 45 December 12, 2005 TA-seminar/Fermilab
GLAST LAT simulations EGRET intensity (>100 Me. V) |b| < 20° LAT simulation (>100 Me. V) Seth Digel Igor V. Moskalenko 46 December 12, 2005 TA-seminar/Fermilab
GLAST LAT: The Gamma-Ray Sky This is an animation that steps from 1. EGRET (>100 Me. V), to 2. LAT (>100 Me. V), to 3. LAT (>1 Ge. V) EGRET Me. V, 1 Simulated LAT (>1 Ge. V, 1 yr)yr) (>100 Me. V) Seth Digel Igor V. Moskalenko 47 December 12, 2005 TA-seminar/Fermilab
Conclusions I Accurate measurements of nuclear species in CR, secondary positrons, antiprotons, and diffuse γ-rays simultaneously may provide a new vital information for Astrophysics – in broad sense, Particle Physics, and Cosmology. Hunter et al. region: l=300°-60°, |b|<10° Gamma rays: GLAST is scheduled to launch in 2007 – diffuse gamma rays is one of its priority goals B/C Be 10/Be 9 Zh increase Ek, Me. V/nucleon Igor V. Moskalenko 48 Dark Matter CR species: New measurements at LE & HE simultaneously (PAMELA, Super-TIGER, AMS…) Ek, Me. V/nucleon December 12, 2005 TA-seminar/Fermilab
Conclusions II Antiprotons: PAMELA (2006), AMS (2008) and a new BESSpolar instrument to fly a longduration balloon mission (in 2004, 2006…), we thus will have more accurate and restrictive antiproton data Positrons: PAMELA (2006), AMS (2008): accurate and restrictive positron data HE electrons: Several missions are planned to target specifically HE electrons CERN Large Hadronic Collider – will address SUSY In few years we may expect major breakthroughs in Astrophysics and Particle Physics ! Igor V. Moskalenko 49 December 12, 2005 TA-seminar/Fermilab
Thank you ! Igor V. Moskalenko 50 December 12, 2005 TA-seminar/Fermilab
Backup slides Igor V. Moskalenko 51 December 12, 2005 TA-seminar/Fermilab
Isotopic Production Cross Sections of Li. Be. B Semi-empirical systematics (Webber, ST) are not always correct. Results obtained by different groups are often inconsistent and hard to test. Very limited number of nuclear measurements: Evaluating the cross section is very laborious and can’t be done without modern nuclear codes. Use LANL nuclear database and modern computer codes. ST W Igor V. Moskalenko 52 December 12, 2005 TA-seminar/Fermilab
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