Документ взят из кэша поисковой машины. Адрес оригинального документа : http://hea.iki.rssi.ru/conf/hea2007/presentations/25.12.2007/03-ptuskin.pdf Дата изменения: Wed Jan 30 21:12:48 2008 Дата индексирования: Tue Oct 2 01:11:42 2012 Кодировка:

Acceleration of ultra-high energy cosmic rays by cluster accretion shocks
V.S. Ptuskin, S.I. Rogovaya, V.N. Zirakashvili
IZMIRAN
HEA-2007


all-particle spectrum of cosmic rays at the Earth
modulation by solar wind

E

-2 .7

E

-3 .1

GZK


energy losses of ultra-high energy cosmic rays in interstellar and intergalactic space
E
microwave & FIR background
c

E

c,Fe

· pair production · pion production

p pe+ep N
19

energy loss time z=0 expansion pairs

GZK cutoff at Ec ~ 6в10

eV

G re i s e n 1 9 6 6 ; Z a t s e p i n & K u z m i n 1 9 6 6

pairs photodisintegration pions

· photodisintegration of nuclei E
c,Fe

~ 2в 10

20

eV S t e c k e r 1 9 6 9

· Universe expansion - (1/E) (dE/dt)
adiabatic

=H

I n o u e e t a l. 2 0 0 7

H0=100h km/(s Mpc), h=0.71


rL= 10вE19/(ZвB G ) kpc
limit of p/He acceleration in SNR ? mass composition
Galactic extragalactic

black body cutoff

G a l a c t i c c o m p o n e n t : a c c e l e ra t i o n i n S N R s
w i t h d i s p e rs i o n o f S N & S N R p a ra m e t e r s o r e a r l y t r a n s i t i o n t o e x t ra g a l . c o m po ne nt + O B s t a r a s s o c i a t i o n s , y o u n g p u l s a rs , G a l a c t i c w i n d e t c .

e x t ra g a l a c t i c c o m pN onm an te:t aA. G9N5 ;& ere zd i oy e t laa.x i e7 ;,K GnR Bt , o re n l 1 9 B r a in s k g a l 1 9 9 s a g e 1 c o l l i d i n g g a l a x i e sa,l....9 9,6 , 1 9 9 7 , 2 0 0 5 ;
O s t ro w s k i e t a l . 2 0 0 2 ; I n o u e e t a l . 2 0 0 5 , 2 0 0 7 ;


cluster accretion shocks
K es het et a l 2003

u R
sh

sh

galaxy cluster



shock

self-similar solution B e rt s c h in g e r 1 9 8 5 ass function B a h c a l l & C e n 1 9 9 3

M ncl ( > M ) = - * M M * = . h - M sol M < < - M sol h

exp

M - h Mpc M*
-

-

(within r = .h Mpc)

M Rsh = . cl h - / Mpc M sol / M ush = . cl h/ km/s M sol = b c , n = - cm -
filaments

/


Fe diffusive shock accelerationr

m i 1 9 4 9 , K ry m s k y 1 9 7 7 , B e l l 1 9 7 8 compression ratio

roughly

u
max

sh

ush/

Ncr ~ (E - E

)

B

Ncr ~ E

-

acceleration efficiency

cr = 2Fcr/(ush3)
energy flux of runaway particles, cr<1

E Pc
Emax
r

max

shock


+2 = -1
/

mhd turbulence in shock precursor is created selfconsistently by strongly driven Bell streaming instability of runaway protons P o s t e r Z i ra k a s h v i l i & P tu s k in

u sh Z cr km/

s - cm - R setting-up time t sh . ush amplified field B . cr/ µ G at

n

Rsh Mpc

eV

yr B = - µ G


characteristics of particle acceleration by cluster accretion shocks
· e n e rg e t i c s 1 0 4 0 e rg /(s M p c 3)
a t p re s e n t epoc h, z = 0

SN 3в10

-1

AGN 1

c lu s te r in G R B a c c re t i o n c o s m i c r a y s 3 в 1 0 -2 a t < 1 0 1 5 m aV g (Sla x i e l a NR 3 в 1 0 -4 1 0 nor 2 в 1 0 -3 a t 1 0 1 8 -1 0 2 0 e V
X / m e c h a n ic a l

e

m e c h a n i c a l b o l o m e t ri c lu m in o s ity

· o b s e rv e r i s u p s t re a m o f t h e s h o c k : a v e ra g e s o u r c e p o w e r d e n s it y is a c o n v o lu t io n o f ~ (E ­ E m a x (M c l)) w i t h c l u s t e r m a s s fu n c t i o n a t i o n a g a i n s t e n e rg y l o s s : E m a x ,F e < 2 в 1 0 2 0 e V a t t h e s o u rc e · a s s u m e d s o u rc e c o m p o s i t i o n : a s i n G a l a c t i c c o s m i c r a y s (w h e re h e a v y e l e m e n t a b u n d a n c e i s s t ro n g l y e n h a n c e d ) b u t s u p p re s s e d b y в 0 .2 m e t a l c o n t e n t (A > 4 )


cosmic ray flux at the Earth after propagation through CMBR & FIRB ( ), preliminary

cr

= 0.7, no source evolution, data:

-HiRes 2007, -Auger 2007

inferred Galactic component


Conclusion
Particle acceleration by cluster accretion shocks can be an efficient source of ultra high energy cosmic rays at 10
18

to 1020 eV.

It is characterized by favorable energetics, heavy nuclear composition at highest energies, and has a severe limit on particle energy at the source E
max,F

< 2в1020 eV. e