Igor V. Moskalenko (Stanford) Challenges in Astrophysics of CR (knee--) & γ-rays Intro to the...
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Transcript of Igor V. Moskalenko (Stanford) Challenges in Astrophysics of CR (knee--) & γ-rays Intro to the...
Igor V. Moskalenko Igor V. Moskalenko (Stanford)(Stanford)
Challenges in AstrophysicsChallenges in Astrophysics
of CR (knee--) & of CR (knee--) & γγ-rays-rays
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
Igor V. Moskalenko 2 December 12, 2005 TA-seminar/Fermilab
CR Interactions in the Interstellar Medium
ee++--
PPHeHe
CNOCNO
X,X,γγ
gas
gas
ISRF
ee++--
ππ++--
PP__
LiBeBLiBeB
ISMISM
diffusiondiffusion energy losses energy losses reaccelerationreacceleration convectionconvection etc.etc.
π0
synchrotron
IC
bremss
Chandra
GLAST
ACEhelio-modulation
pp
42 sigma (2003+2004 data)
HESS Preliminary
SNR RX J1713-3946SNR RX J1713-3946
PSF
B
HeHeCNOCNO Fl
ux
20 GeV/n
CR species: Only 1 location modulation
ee++--
ππ++--
PAMELABESS
AMS
Igor V. Moskalenko 3 December 12, 2005 TA-seminar/Fermilab
Elemental Abundances: CR vs. Solar System
CR abundances: ACE
Solar system abundances
LiBeB
CNO
F
Fe
ScTiV
CrMn
Si
Cl
Al
O
Na
S
Long propagation history…
Igor V. Moskalenko 4 December 12, 2005 TA-seminar/Fermilab
Nuclear component in CR: What we can learn?
Propagation parameters:
Diffusion coeff., halo size, Alfvén speed,
convection velosity…
Energy markers:Reacceleration,
solar modulation
Local medium: Local Bubble
Material & acceleration sites,
nucleosynthesis (r-vs. s-processes)
Stable secondaries:
Li, Be, B, Sc, Ti, V Radio (t1/2~1
Myr): 10Be, 26Al, 36Cl,
54Mn K-capture: 37Ar,49V, 51Cr, 55Fe,
57Co
Short t1/2 radio 14C
& heavy Z>30 Heavy Z>30:
Cu, Zn, Ga, Ge, Rb
Nucleo-
synthesis:
supernovae,
early universe,
Big Bang…
Solar
modulation
Diffuse γ-raysGalactic,
extragalactic: blazars, relic
neutralino
Dark Matter (p,đ,e+,γ)-
Igor V. Moskalenko 5 December 12, 2005 TA-seminar/Fermilab
Diffuse Galactic Gamma-ray Diffuse Galactic Gamma-ray EmissionEmission
~80% of total Milky Way luminosity at HE !!!
Tracer of CR (p, e−) interactions in the ISM (π0,IC,bremss):o Study of CR species in distant locations (spectra & intensities)
CR acceleration (SNRs, pulsars etc.) and propagationo Emission from local clouds → local CR spectra
CR variations, Solar modulationo May contain signatures of exotic physics (dark matter etc.)
Cosmology, SUSY, hints for accelerator experimentso Background for point sources (positions, low latitude sources…)
Besides:o “Diffuse” emission from other normal galaxies (M31, LMC,
SMC) Cosmic rays in other galaxies !
o Foreground in studies of the extragalactic diffuse emissiono 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 6 December 12, 2005 TA-seminar/Fermilab
Transport Equations ~90 (no. of CR species)
ψψ((rr,p,t),p,t) – – density per total momentum
df
Vpdt
dp
p
ppppDp
p
Vxx
D
prqt
tpr
3
1
22
][
),(),,(
sources (SNR, nuclear reactions…)sources (SNR, nuclear reactions…)
convection convection (Galactic wind)
diffusiondiffusion
diffusive diffusive reacceleration reacceleration
(diffusion in the momentum space)
E-lossE-loss
fragmentationfragmentation radioactive decayradioactive decay
+ boundary conditions
Igor V. Moskalenko 7 December 12, 2005 TA-seminar/Fermilab
CR Propagation: Milky Way Galaxy
Halo
Gas, sources
100
pc 40 kpc
4-12
kpc
0.1-0.01/ccm
1-100/ccm
Intergalactic space
1 kpc ~ 3x1018 cm
R Band image of NGC8911.4 GHz continuum (NVSS), 1,2,…64 mJy/ beam
Optical image: Cheng et al. 1992, Brinkman et al. 1993Radio contours: Condon et al. 1998 AJ 115, 1693
NGC891
Sun
“Flat halo” model (Ginzburg & Ptuskin 1976)
Halo
Igor V. Moskalenko 8 December 12, 2005 TA-seminar/Fermilab
A Model of CR Propagation in the Galaxy
Gas distribution (energy losses, Gas distribution (energy losses, ππ00, brems), brems)
Interstellar radiation field (IC, eInterstellar radiation field (IC, e±± energy losses) energy losses)
Nuclear & particle production cross sectionsNuclear & particle production cross sections
Gamma-ray production: brems, IC, Gamma-ray production: brems, IC, ππ00
Energy losses: Energy losses: ionization, Coulomb, brems, IC, synchionization, Coulomb, brems, IC, synch
Solve transport equations for all CR speciesSolve transport equations for all CR species
Fix propagation parametersFix propagation parameters
“Precise” Astrophysics
Igor V. Moskalenko 9 December 12, 2005 TA-seminar/Fermilab
How It Works: Fixing Propagation Parameters
Using secondary/primary nuclei ratio & flux:•Diffusion coefficient and its index•Propagation mode and its parameters
(e.g., reacceleration VA, convection Vz)
Radioactive isotopes:
Galactic halo size Zh
Zh increase
B/C
Be10/Be9
Inte
rste
llar
Ek, MeV/nucleon
Ek, MeV/nucleon
E2 Flux
Carbon
Ek, GeV/nucleon
Igor V. Moskalenko 10 December 12, 2005 TA-seminar/Fermilab
Peak in the Secondary/Primary Ratio
• Leaky-box model: fitting path-length distribution -> free function
B/C
• Diffusion models: Diffusive reacceleration Convection Damping of interstellar
turbulence Etc.
Accurate measurements in a wide energy range may help to distinguish between the models
EEkk, MeV/nucleon, MeV/nucleon
too sharp max?
Igor V. Moskalenko 11 December 12, 2005 TA-seminar/Fermilab
Distributed Stochastic Reacceleration
Fermi 2-nd order mechanism
BB
Scattering on magnetic turbulences Dpp~ p2Va
2/D
D ~ vR1/3 - Kolmogorov spectrum
Icr
E
strongreaccelerati
onweakreacceleration
ΔE
Simon et al. 1986Seo & Ptuskin
1994
1/3
Dxx = 5.2x1028 (R/3 GV)1/3cm-2 s-1
Va = 36 km s-1
γ ~ R-δ, δ=1.8/2.4 below/above 4 GV
Igor V. Moskalenko 12 December 12, 2005 TA-seminar/Fermilab
Convection
Galactic wind
Escape length
Xe
E
vR-0.6
wind orturbulentdiffusion
resonantdiffusion
Jones 1979
problem: too broad sec/prim peak
D~R0.
6
Dxx = 2.5x1028 (R/4 GV)0.6cm-2 s-1
dV/dz = 10 km s-1 kpc-1
γ ~ R-δ, δ=2.46/2.16 below/above 20 GV
Igor V. Moskalenko 13 December 12, 2005 TA-seminar/Fermilab
Damping of Interstellar Turbulence
p
l(p)
Iroshnikov-Kraichnan cascade:
Kolmogorov cascade:
W(k)
k
dissipation
1/1012cm1/1020cm
Simplified case:
• 1-D diffusion• No energy losses
Mean free path
nonlinearcascade
Ptuskin et al. 2003, 2005
Igor V. Moskalenko 14 December 12, 2005 TA-seminar/Fermilab
LiBeB: Major Production Channels
Propagated Abundance * Cross-sectionPropagated Abundance * Cross-section
Be B
C
Li
N
OLi6
79 10
1113
1514
•Well defined (65%):C12, O16 ->LiBeBN14 -> Be7
(see Moskalenko & Mashnik 28 ICRC, 2003)
•Few measurements:C13,N -> LiBeBB -> BeB
•Unknown:LiBeB,C13,N -> LiBeB
“Tertiary” reactions also important! -35%
12 16
A=
Igor V. Moskalenko 15 December 12, 2005 TA-seminar/Fermilab
Effect of Cross Sections: Radioactive Effect of Cross Sections: Radioactive SecondariesSecondaries
Different Different size from different ratios…size from different ratios…
Zhalo,kpc
STST
WW
2727Al+pAl+p2626AlAl
•ErrorsErrors in CR measurements (HE & LE) in CR measurements (HE & LE)•ErrorsErrors in production cross sections in production cross sections•ErrorsErrors in the lifetime estimates in the lifetime estimates•DifferentDifferent origin of elements (Local origin of elements (Local Bubble ?)Bubble ?)
natnatSi+pSi+p2626AlAl
WW
STST
TT1/21/2==??
Ek, MeV/nucleon
Igor V. Moskalenko 16 December 12, 2005 TA-seminar/Fermilab
Wherever you look, the GeV -ray excess is there !
4a-f
EGRET dataExcess: x2
Igor V. Moskalenko 17 December 12, 2005 TA-seminar/Fermilab
Reacceleration Model vs. Plain Reacceleration Model vs. Plain DiffusionDiffusion
Plain Diffusion
(Dxx~β-3 R0.6)
DiffusiveReacceleration
B/C ratio
Antiproton flux
Antiproton flux
B/C ratio
Excess: x2
Igor V. Moskalenko 18 December 12, 2005 TA-seminar/Fermilab
Positron Excess ?
HEAT (Beatty et al. 2004)
GALPROP
GALPROP
1E, GeV
10
e+/e e+/e
HEAT 2000 HEAT 1994-95
HEAT combined
1E, GeV
10
Q: Are all the excesses connected?Q: Are all the excesses connected?
A: “Yes” and “No”A: “Yes” and “No”
Same progenitor (CR p or DM) for pbars, e+’s, γ’s
Systematic errors of different detectors
E > 6 GeV
Excess: 20%
Igor V. Moskalenko 19 December 12, 2005 TA-seminar/Fermilab
CR Source Distribution
SNR source
The CR source (SNRs, pulsars) distribution is too narrow to match the CR distribution in the Galaxy assuming XCO=N(H2)/WCO=const (CO is a tracer of H2)
Lorimer 2004
PulsarsCR afterpropagation
diffuse γ-raydistribution
Igor V. Moskalenko 20 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 GeV) is problematic.
May indicate:• systematic or cross-
calibration errors• different origin of LE
and HE CR
=(Calcs-Exp)/Exp
Fit quality
Relat. deviation
Igor V. Moskalenko 21 December 12, 2005 TA-seminar/Fermilab
Hypotheses…
Provide Provide good agreementgood agreement with all with all data (diffuse gammas, pbars, e+)data (diffuse gammas, pbars, e+) CR intensity variationsCR intensity variations Dark Matter signals Dark Matter signals
Other possibilities:Other possibilities:
Harder CR spectrum (protons, electrons) Harder CR spectrum (protons, electrons) – deviates – deviates limits from pbars, gamma-ray profileslimits from pbars, gamma-ray profiles
Influence of the Local Bubble (local component)Influence of the Local Bubble (local component) – – helps with pbars, but doesn’t help with diffuse helps with pbars, but doesn’t help with diffuse gammasgammas
Igor V. Moskalenko 22 December 12, 2005 TA-seminar/Fermilab
Diffuse emission models
0.5-1 GeV
>0.5 GeV
Dark MatterCosmic Ray
Spectral VariationsEGRET “GeV Excess”
There are two possible BUT fundamentally different explanations of the excess, in terms of exotic and traditional physics:
Dark MatterCR spectral variations
Both have their pros & cons.
from Strong et al. ApJ (2004)from de Boer et al. A&A (2005)
from Hunter et al. ApJ (1997)
Igor V. Moskalenko 23 December 12, 2005 TA-seminar/Fermilab
CR Variations in Space & Time
Historical variations Historical variations of CR of CR intensityintensity: : ~40kyr~40kyr ( (1010Be in South Polar ice), Be in South Polar ice), ~2.8Myr ~2.8Myr ((6060Fe in deep sea FeMn Fe in deep sea FeMn crust)crust)
Konstantinov et al. 1990
Electron/positron energy losses
Different “collecting” areas A vs. p (σ~30 mb)(different sources ?)
SN
R n
um
ber
den
sit
y
R, kpc
sun
sun
More frequent SN in the spiral arms
Igor V. Moskalenko 24 December 12, 2005 TA-seminar/Fermilab
Electron Fluctuations/SNR stochastic events
GeV electrons 100 TeV electrons
GALPROP/Credit S.Swordy
Energy losses
107 yr
106 yr
Bremsstrahlung
1 TeV
Ionization
Coulomb
IC, synchrotron
1 GeV
Ekin, GeV
E(d
E/d
t)-1,y
r
Electron energy loss timescale:
1 TeV: ~300 kyr 100 TeV: ~3 kyr
Igor V. Moskalenko 25 December 12, 2005 TA-seminar/Fermilab
GeV excess: Optimized/Reaccleration model
Uses Uses all skyall sky and antiprotons & gammas and antiprotons & gammas to fix the nucleon and electron spectrato fix the nucleon and electron spectra
Uses Uses antiprotonsantiprotons to fix to fix the the intensityintensity of CR nucleons @ HE of CR nucleons @ HE
Uses Uses gammasgammas to adjust to adjust the nucleon spectrum at LEthe nucleon spectrum at LE the the intensity intensity of the CR electrons of the CR electrons
(uses also synchrotron index)(uses also synchrotron index)
Uses EGRET data Uses EGRET data up to 100 GeVup to 100 GeV
protonsprotonselectronselectrons
x4x4
x1.8
antiprotonsantiprotons
EEkk, GeV, GeV
EEkk, GeV, GeV
EEkk, GeV, GeV
pbarse+ -fluxγ-rays
Igor V. Moskalenko 26 December 12, 2005 TA-seminar/Fermilab
Secondary e± are seen in γ-rays !
Lots of new effects !
Improves an agreement at LE
brems
IC
Heliosphere: e+/e~0.2
electronselectrons
positronspositrons
sec.
Igor V. Moskalenko 27 December 12, 2005 TA-seminar/Fermilab
Diffuse Gammas at Different Sky RegionsDiffuse Gammas at Different Sky Regions
Intermediate latitudes:l=0°-360°,10°<|b|<20°
Outer Galaxy:l=90°-270°,|b|<10°
Intermediate latitudes:l=0°-360°,20°<|b|<60°
Inner Galaxy:l=330°-30°,|b|<5°
Hunter et al. region:l=300°-60°,|b|<10°
l=40°-100°,|b|<5°
corrected
Milagro
Igor V. Moskalenko 28 December 12, 2005 TA-seminar/Fermilab
Longitude Profiles |b|<5Longitude Profiles |b|<5°°
50-70 MeV
2-4 GeV
0.5-1 GeV
4-10 GeV
Igor V. Moskalenko 29 December 12, 2005 TA-seminar/Fermilab
Latitude Profiles: Inner Galaxy
50-70 MeV 2-4 GeV0.5-1 GeV
4-10 GeV 20-50 GeV
Igor V. Moskalenko 30 December 12, 2005 TA-seminar/Fermilab
Latitude Profiles: Outer Galaxy
50-70 MeV
2-4 GeV
0.5-1 GeV
4-10 GeV
Igor V. Moskalenko 31 December 12, 2005 TA-seminar/Fermilab
Anisotropic Inverse Compton Scattering
Electrons in the halo see anisotropic radiation Observer sees mostly head-on collisions
e-
e-
head-on:large boost &more collisions
γγ
small boost &less collisions
γ
sun
Energy density
Z, kpc
R=4 kpc
Important @ high
latitudes !
Igor V. Moskalenko 32 December 12, 2005 TA-seminar/Fermilab
Extragalactic Gamma-Ray BackgroundExtragalactic Gamma-Ray Background
Predicted vs. observedPredicted vs. observed
E, MeVE, MeV
EE22xFxF
Sreekumar et al. 1998Sreekumar et al. 1998
Strong et al. 2004Strong et al. 2004Elsaesser & Mannheim,
astro-ph/0405235
•Blazars•Cosmological neutralinos
EGRB in differentdirections
Igor V. Moskalenko 33 December 12, 2005 TA-seminar/Fermilab
Distribution of CR Sources & Gradient in the CO/H2
CR distribution from diffuse gammas (Strong & Mattox 1996)
SNR distribution (Case &Bhattacharya 1998)
sun
XXCOCO=N(H=N(H22)/W)/WCOCO::
Histo –This work, Strong et al.’04----- -Sodroski et al.’95,’971.9x1020 -Strong & Mattox’96~Z-1 –Boselli et al.’02~Z-2.5 -Israel’97,’00, [O/H]=0.04,0.07 dex/kpc
Pulsar distribution Lorimer 2004
Igor V. Moskalenko 34 December 12, 2005 TA-seminar/Fermilab
Again Diffuse Galactic Gamma Rays
More IC in the GC –better
agreement !
The pulsar distribution vs. R falls too fast OR
larger H2/CO gradient
Very good agreement !Very good agreement !
2-4 GeV
Igor V. Moskalenko 35 December 12, 2005 TA-seminar/FermilabE.Bloom’05
Igor V. Moskalenko 36 December 12, 2005 TA-seminar/Fermilab
Matter, Dark Matter, Dark Energy…
Ω ≡ ρ/ρcrit
Ωtot =1.02 +/−0.02
ΩMatter =4.4%+/−0.4%
ΩDM =23% +/−4%
ΩVacuum =73% +/−4%“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)
SUSY DM candidate has also other reasons to exist -particle physics…
Igor V. Moskalenko 37 December 12, 2005 TA-seminar/Fermilab
Where is the DM ?!
What (flavors): Neutrinos ~ visible matter Super-heavy relics: “wimpzillas” Axions Topological objects “Q-balls” Neutralino-like, KK-like
Where (places): Galactic halo, Galactic center The sun and the Earth
How (tools): Direct searches
– low-background experiments (DAMA, EDELWEISS)
– neutrino detectors (AMANDA/IceCUBE)
– Accelerators (LHC) Indirect searches
– CR, γ’s (PAMELA,GLAST,BESS)
from E.Bloom presentation
Igor V. Moskalenko 38 December 12, 2005 TA-seminar/Fermilab
Example “Global Fit:” diffuse Example “Global Fit:” diffuse γγ’s, pbars, ’s, pbars, positrons positrons
Look at the combined (pbar,e+,γ) data Possibility of a successful “global fit”
can not be excluded -non-trivial !
pbars
e+
γ
GALPROP/W. de Boer et al. hep-ph/0309029GALPROP/W. de Boer et al. hep-ph/0309029
Supersymmetry: MSSM (DarkSUSY) Lightest neutralino χ0
mχ ≈ 50-500 GeV S=½ Majorana
particles χ0χ0−> p, pbar, e+, e−,
γ
Igor V. Moskalenko 39 December 12, 2005 TA-seminar/Fermilab
Longitude and Latitude Distr. E >0.5 GeV
In the plane (± 50 in lat.) Out of the plane (± 300 in long..)
Igor V. Moskalenko 40 December 12, 2005 TA-seminar/Fermilab
x y
z
2003, Ibata et al, Yanny et al.
Outer RingInner Ring
DM halo
diskbulge
Rotation Curvexy
xz
xy
xz
Expected Profile (NFW)
Halo profile
Isothermal Profile
v2M/r=cons.and
M/r3
1/r2
for const.rotation
curve
Observed Profile: EGRET data+ GALPROP
Executive Summary –de Boer et al. astro-ph/0408272
Page Number
PAMELA: Secondary to Primary ratios
plots: M.Simon
LE: sec/prim peak: one instrument -no cross calibration errors
HE: Dxx(R)
Igor V. Moskalenko 42 December 12, 2005 TA-seminar/Fermilab
PAMELA positrons
A factor of 2 will become statistically significant
Measuring absolute flux not ratio
Solar minimum conditions
After 3 years
Igor V. Moskalenko 43 December 12, 2005 TA-seminar/Fermilab
PAMELA antiprotons
After 3 years
Igor V. Moskalenko 44 December 12, 2005 TA-seminar/Fermilab
Igor V. Moskalenko 45 December 12, 2005 TA-seminar/Fermilab
A.Morselli
Igor V. Moskalenko 46 December 12, 2005 TA-seminar/Fermilab
GLAST LAT simulations
EGRET intensity (>100 MeV)
LAT simulation (>100 MeV)
|b| < 20°
Seth Digel
Igor V. Moskalenko 47 December 12, 2005 TA-seminar/Fermilab
GLAST LAT: The Gamma-Ray Sky
EGRET(>100 MeV)
Simulated LAT (>100 MeV, 1 yr)Simulated LAT (>1 GeV, 1 yr)
This is an animation that steps from 1. EGRET (>100 MeV), to 2. LAT (>100 MeV), to 3. LAT (>1 GeV)
Seth Digel
Igor V. Moskalenko 48 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.
Gamma rays: GLAST is scheduled to launch in 2007 – diffuse gamma rays is one of its priority goals
CR species: New measurements at LE & HE simultaneously (PAMELA, Super-TIGER, AMS…)
Hunter et al. region:l=300°-60°,|b|<10°
Dark Matter
Zh increase
Be10/Be9
EEkk, MeV/nucleon, MeV/nucleon
B/C
EEkk, MeV/nucleon, MeV/nucleon
Igor V. Moskalenko 49 December 12, 2005 TA-seminar/Fermilab
Conclusions II
Antiprotons: PAMELA (2006), AMS (2008) and a new BESS-polar instrument to fly a long-duration balloon mission (in 2004, 2006…), we thus will have more accurate and restrictive antiproton data
HE electrons: Several missions are planned to target specifically HE electrons
In few years we may expect major breakthroughs in Astrophysics and Particle Physics !
CERN Large Hadronic Collider – will address SUSY
Positrons: PAMELA (2006), AMS (2008): accurate and restrictive positron data
Igor V. Moskalenko 50 December 12, 2005 TA-seminar/Fermilab
Thank you !
Igor V. Moskalenko 51 December 12, 2005 TA-seminar/Fermilab
Backup slides
Igor V. Moskalenko 52 December 12, 2005 TA-seminar/Fermilab
Isotopic Production Cross Sections of LiBeB
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.
W
ST