Origin of high-energy cosmic rays

Vladimir Ptuskin

IZMIRAN

knee

Galactic extragalactic

GZK cutoff KpcEeVg

μG

Er = 1×

Z×B

JXE3

Sun

close binary

Galactic disk

pulsar

SNR

stellar wind

AGN

GRB

interacting galaxies

Ncr ~ 10-10 cm-3 - total number density in the

Galaxy

wcr ~ 1.5 eV/cm3 - energy density

Emax ~ 3x1020 eV - max. detected energy

rg ~ 1×E/(Z×3×1015 eV) pc - Larmor radius at

B=3x10-6 G

A1 ~ 10-3 – anisotropy at 1 – 100 TeV, slow

diffusion

Fermi bubble

GC

WMAP haze

cosmic ray halo

cosmologicalshocks

RXJ1713.7-3945 H.E.S.S

Cosmic rays of Galactic origin:acceleration in supernova remnants and propagation in interstellar magnetic fields

M51

Jcr(E) = Qcr(E)×Te(E)

source confinement time of CR in the Galaxy;~ 108 yr at 1 GeV

~ 15% of SN kinetic energy transfer to cosmic rays,

basic diffusion model

2cm /s at 1 GeV,

228

e

a

HT D 3×10

2D

D p / Z , a = 0.3...0.6

H = 4 kpc, R = 20 kpc

sγ = 2.1...2.4 sourcespectrum

Ginzburg & Syrovatskii 1964, Berezinskii et al 1990,Strong & Moskalenko 1998 (GALPROP) , Strong et al 2007

“microscopic” theory: resonance scattering rg = 1/k, D ~

0.3vrgBtot2/Bres

2

-1snν = (30 yr)

Larmor radius wave number

sh shu R> 10

D(p)

, s-γs

σ + 2J ~ p γ = = 2

σ -1

shmax sh

uE 0.3 Ze B R

c

- D(р) should be anomalously small both upstream and downstream; CR streaming creates turbulence in shock precursor Bell 1978; Lagage & Cesarsky 1983; McKenzie & Vőlk 1982 …

diffusive shock accelerationFermi 1949, Krymsky 1977, Bell 1978, …

Bohm limit

DB=vrg/3: Emax ≈ 1014 Z eV

SNR

ushshock

compression ratio = 4

-condition of CR acceleration

- Hillas criterion !

in young SNR from synchrotron X-rays obs. Koyama et al 1995 …

& theory of CR streaming instability Bell & Lucek 2000, Bell 2004 …

for Bism = 5 10-6 G

2ism 10B/B ~

for testparticles !

numerical simulation of cosmic-ray acceleration in SNRPtuskin, Zirakashvili & Seo 2010

- spherically symmetric hydrodynamic eqs. including CR pressure + diffusion-convection eq. for cosmic ray distribution function (compare to Berezhko et al. 1996, Berezhko & Voelk 2000; Kang & Jones 2006)

- Bohm diffusion in amplified magnetic field B2/8π = 0.035 ρu2/2 ( Voelk et al. 2005 empirical; Bell 2004, Zirakashvili & VP 2008 theoretical)

- account for Alfvenic drift w = u + Va

upstream and downstream

- relative SNR rates: SN Ia : IIP : Ib/c : IIb = 0.32 : 0.44 : 0.22 : 0.02 Chevalier 2004, Leaman 2008, Smart et al 2009

15 1/6 -2/3knee sn,51 ej

•15 -1

knee sn,51 -5 w,6 ej

p c Z = 1.1×10 Ε n M eV,

p c Z = 8.4×10 Ε M u M eV

«knee» is formedat the beginningof Sedov stage

protons only

44 ( ) /sn sncp F p

calculated interstellar spectra produced by Type Ia, IIP, Ib/c, IIb SNRs(normalized at 103 GeV)

data from HEAO 3, AMS, BESS TeV, ATIC 2,TRACER experiments

data from ATIC 1/2, Sokol, JACEE, Tibet, HEGRA,Tunka, KASCADE, HiRes and Auger experiments

spectrum of all particles

<lnA> based on <Xmax>; data from Hoerandel 2007

0.54

pcD Ze

composition

solar modulation

more details:

spectra of p and He are differenthardening above 200 GeV/nucleon

concave source spectrum; acceleration at reverse shock; shock goes through Hewind of progenitor W-R star

different types of SN and different types of nuclei

Ptuskin et al. 2011

structure above the knee

Sveshnikova et al. 2011

single source modelof the knee

Erlykin & Wolfendale 1997Erlykin et al. 2011

Cosmic rays of extragalactic origin:acceleration in AGN jets andpropagation through backgroundradiation in the expanding Universe

Greisen 1966; Zatsepin & Kuzmin 1966energy scales are multiplied by1.2, 1.0, 0.75, 0.625 forAuger, HiRes, AGASA, & Yakutsk

Aloisio et al 2007

Auger – heavy composition; anisotropy (69 events at >57 EeV)

Abreu et al 2010, Matthiae 2010, PAO 2010

HiRes – proton composition; no significant anisotropy (13 events)

Abbasi et al 2009, Sokolsky et al 2010

first results of Telescope Array (13 events) support HiRes

Pierre Auger Observatory, 69 events at E > 5.5 1019 eV (with Swift-BAT AGN density map) Abreu et al 2010

extragalactic sources

needed in CR SN AGN jets GRB newly born accretion on at Е > 1019.5 eV fast magnetars galaxy clusters 3 10-4 (Auger) 3 10-1 3 3 10- 4 10-3 10 kin. & 6 10-2 for X/gamma rotation strong shocks

8 10-3 for E>109 eV Lkin > 1044 erg/s

energy release in units 1040 erg/(s Mpc3)

FR II + RLQ

low-luminosity AGN

Koerding et al 2007

maximum energy of accelerated particlesLovelace 1976, Biermann & Strittmatter 1987, Blandford 1993, Norman et al 1995, Waxman 1995, Farrar & Gruzinov 2009, Lemoine & Waxman 2009, Ptitsyna & Troitsky 2010

22 3 2

jet

0.5 6

jetB

L c R L u R

E = Ze×β×B×lmax

2

1/2

1/2

max jet max

(4 )

86

cr cr

cr

cr

w u

B w

E Ze L E Ze Lc c

1/2

jet

η20 1/2 1/2 20 1/2cr2.7×10 Zβ L eV 1×10 Zβ L eVjet,45 jet,450.1

- Hillas criterion

- optimistic estimates of Emax for not ultrarelativistic jets

general electrodynamic estimate shock acceleration

- power of magnetized flow

proton-electron jet

Bell 2004

jet radiusjet velocity

Berezinsky & Grigoreva 1988,Allard et al 2005, Berezinsky et al. 2006

Galactic

Galactic

empirical dip model

empirical ankle transition model

VP, Rogovaya, Zirakashvili 2011

account for dmin(Ljet)

Auger data 30% of Fe

Allard 2009heavy composition

Conclusions

Cosmic ray origin scenario where supernova remnants serve as principle accelerators of cosmic rays in the Galaxy is strongly confirmed by recent numerical simulations. SNRs can provide cosmic ray acceleration up to 5x1018 eV.

High-accuracy measurements reveal deviations of cosmic ray spectra from plain power laws both below and above the knee that requires theory refinement.

More data on spectrum, composition, and anisotropy are needed in the energy range 1017 to 1019 eV, where transition from Galactic to extragalactic component occurs.

Understanding discrepancy between Auger and HiRes results on composition and anisotropy is necessary for understanding of cosmic ray origin at the highest energies.