Igor V. Moskalenko (Stanford) GALPROP Model for Galactic CR propagation and diffuse γ -ray...

Igor V. Moskalenko (Stanford)

GALPROP Model for Galactic CRGALPROP Model for Galactic CR

propagation and diffuse propagation and diffuse γγ-ray -ray

emissionemission

Igor V. Moskalenko 2 October 24, 2006 SCIPP/UCSC

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


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…


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)-


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


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


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


Wherever you look, the GeV -ray excess is there !

4a-f

EGRET dataExcess: x2


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


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%


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)


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


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


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.


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


Longitude Profiles |b|<5Longitude Profiles |b|<5°°

50-70 MeV

2-4 GeV

0.5-1 GeV

4-10 GeV


Latitude Profiles: Inner Galaxy

50-70 MeV 2-4 GeV0.5-1 GeV

4-10 GeV 20-50 GeV


Latitude Profiles: Outer Galaxy

50-70 MeV

2-4 GeV

0.5-1 GeV

4-10 GeV


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 !


Effect of anisotropic ICS

Galactic latitude, degrees

Ratio anisoIC/isoIC

Intermediate latitudesGC

anti-GCpole

• The anisotropic IC scattering plays important role in modeling the Galactic diffuse emission

• Affects estimates of isotropic extragalactic background


Latitude profile of the outer Galaxy

anisotropic IC

• The aniso IC is maximal (x2) in the outer Galaxy around b=20 -30

• Agreement with data impossible without aniso IC

Latitude

isoIC

bremsstrahlung

0

TotalEG

PRELIMIN

ARY


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


Inverse Compton scattering

©UCAR

The heliosphere is filled with Galactic CR electrons and solar photons

•electrons are isotropic•photons have a radial angular distribution

QED

e

IM, T.Porter, S.Digel: astro-ph/0607521


The ecliptic

Averaged over one year,the ecliptic will be seen as a bright stripe on the sky, but the emission comes from all directions

Galactic plane

GC

ecliptic

>100 MeV

IS spectrum

Modulated 500 MV

Modulated 1000 MV

>1 GeV

Current EGRB

AC

70°


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…


Where is the DM ?!Where is the DM ?!

What (flavors):What (flavors): Neutrinos ~ visible matterNeutrinos ~ visible matter Super-heavy relics: “wimpzillas”Super-heavy relics: “wimpzillas” AxionsAxions Topological objects “Q-balls”Topological objects “Q-balls” Neutralino-like, KK-likeNeutralino-like, KK-like

Where (places):Where (places): Galactic halo, Galactic centerGalactic halo, Galactic center The sun and the EarthThe sun and the Earth

How (tools):How (tools): Direct searches Direct searches

– low-background experiments low-background experiments (DAMA, EDELWEISS)(DAMA, EDELWEISS)

– neutrino detectors neutrino detectors (AMANDA/IceCUBE)(AMANDA/IceCUBE)

– Accelerators (LHC)Accelerators (LHC) Indirect searchesIndirect searches

– CR, CR, γγ’s (PAMELA,GLAST,BESS)’s (PAMELA,GLAST,BESS)

from E.Bloom presentation

GALPROP Web-site:http://galprop.stanford.edu/na_home.html

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Igor V. Moskalenko (Stanford) GALPROP Model for Galactic CR propagation and diffuse γ -ray...

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