COSMIC RAYS P PASQU ASQUALE ALE BL BLASI ASI INAF/ Arc rcet etri Ast Astro rophysical O l Observato atory y
THE ALL -PARTICLE SPECTRUM Knee � 2 nd knee? Dip/Ankle GZK? �
OUTLINE 1. � The supernova paradigm for acceleration 2. � The knee and the knees (chemistry) 3. � The end of Galactic CRs 4. � UHECRs a. � Spectrum b. � Anisotropy c. � Chemical Composition
THE SUPERN THE SUPERNOVA P A PARADIGM ARADIGM P PAR ARTICLE A TICLE ACCELERA CCELERATION TION
TEST P EST PART RTICLE T LE THEORY OF EORY OF DIFFU FUSIVE S E SHOCK AC K ACCELE LERATION ON � = R + 2 R � 1 � 4 1. � POWER LAW SPECTRUM WITH SLOPE 2. � LOW ACCELERATION EFFICIENCY REQUIRED 3. � MAXIMUM ENERGY E max ~1-100 GeV <<Knee �
BEYOND TEST PARTICLES: Non linear DSA � Berezhko & Voelk, PB, Amato & PB, Ellison et al… NON LI NON LINEAR R THEORY EORY DYNAMICAL REACTION � DYNAMICAL REACTION � OF AMPLIFIED B-FIELDS � OF ACCELERATED � CR INDUCED � PARTICLES � B-FIELD AMPLIFICATION � Cosmic r Cosmic ray acceler y acceleration ation up t up to The knee o The knee
DYNAMICAL REACTION !"#$%"&'"( "#$%&'()!*+%,'$#! v %)*+,-./01*(21*+.3( &%9&:'$; ! &4567(8/5)-( ,.0,4567(((((((!/16./,5/( CR TRANSPORT EQUATION � 1. � CONCAVE SPECTRA � � + � 2. � HIGH ACCEL. EFFICIENCY � � � 3. � REDUCED HEATING � MASS, MOMENTUM, ENERGY � 4. � ESCAPE FLUX � CONSERVATION EQUATIONS �
REDUCED REDUCED HEA HEATIN TING G SHOCK MODIFICATION !9<(=>0+6+(?(@>))5)+(ABBC(
MAGNETIC FIELD AMPLIFICATION SMALL PERTURBATIONS IN THE LOCAL � B-FIELD CAN BE AMPLIFIED BY THE � SUPER-ALFVENIC STREAMING OF THE � ACCELERATED PARTICLES � METHOD: Write a Vlasov eq for each particle type Write Maxwell eqs for the fields Perturb them all Check if there are fourier modes that Develop a negative im( w) UNSTABLE MODES
GROWING MODES Amato & PB 2009, Bell 2004 �
NON-RESONANT MODES grow faster only in the early phases of a SN Amato & PB 2009 � 1000 years
SATURATION OF GROWTH ALL RESULTS ARE OBTAINED IN PERTURBATIVE THEORY � BUT THEY LEAD TO NON-PERTURBATIVE CONCLUSIONS ( d B/B>>1). � HARD TO PREDICT THE REAL SATURATION LEVEL (EVEN PIC � SIMULATIONS DISAGREE ON CONCLUSIONS…) � BUT IT IS SUGGES BUT IT IS SUGGESTIVE THA TIVE THAT THE V T THE VAL ALUES INFERRED FR UES INFERRED FROM OM PER PERTURB TURBATIVE TIVE THEOR THEORY HINT T Y HINT TO O � B � 100 µ G
WHY IS IT INTERESTING: � I. Reaching the knee? DB E( PROTON PR ON DB F( KNEE KNEE - ./0 1.&! DB C( DB G( 9543(H+II(J+-45.-( 9K>3LM+I+6>-+5)( !23!!!!!!!!!!!!!!!433 !!!!!!!!!!423!!!!!!!!!!!!!!533! PB, Amato & Caprioli, 2007 � ! 6 3! Amato & PB, 2006 �
WHY I HY IS I S IT I T INT NTEREST ESTING ( G (2)
WHY IS IT INTERESTING: � II. Large B observed? TYPICAL THICKNESS OF FILAMENTS: 10 -2 -10 -3 pc � The synchrotron limited thickness is: � -3/2 � x = 4 D ( E ) � syn ( E ) � 4 pc B µ B � 100 µ Gauss
DYNAMICAL ROLE OF THE AMPLIFIED B-FIELD 1. � LARGE B � HIGHER MAX MOMENTUM P MAX � 2. � HIGHER P MAX � LARGER SHOCK MODIFICATION � 3. � SHOCK MODIFICATION � CONCAVE SPECTRA � 4. � LARGE B � REDUCE MODIFICATION � LESS � CONCAVE SPECTRA (Rtot~10) [Caprioli et al. � 2008] �
NARROW X-RAY RIMS MAGNETIC FIELD MAGNETIC FIELD AMPLIFICATION DAMPING PLASMA SOME B AMPLIFICATION CR INDUCED STILL NEEDED INDUCED (DOWNSTREA (UPSTREAM) M) RIMS ALSO IN THE RADIO ONLY IF @ EMISSION PERPENDIC. SHOCK NO ACCELERATION UP TO THE LARGE PMAX KNEE UNLESS… EFFICIENT ACCELERATION …ACCELERATION IN THE NO RIMS IN THE RADIO BAND PERPENDICULAR REGIME
789:;<=>!! RXJ1713 ?@*A;<=>! 6%+$'B%C!8./(%!D!*E!533F!
THE MISSING LINK BETWEEN � CRs AND ACCELERATED PARTICLES WHAT IS THE SPECTRUM OF CR AT EARTH? � $>L/+5M+<(!9(?(N3>-5(ABBO( P+/>7>,4Q+M+(?(!-.,7+)(ABBC( N(E)E 2 EXPANDING SHELL + ADIABATIC LOSSES DURING THE E SEDOV-TAYLOR PHASE IN IN THE THE ABSENCE OF ABSENCE OF THIS ESC THIS ESCAPE PE � FLUX FL UX ADIAB ADIABATIC L TIC LOSSES OSSES WOULD ULD � MAKE REA MAKE REACHING CHING THE KNEE IMPOSSIBLE THE KNEE IMPOSSIBLE �
ESCAPE FLUX WITH TIME $>L/+5M+<(!9(?(N3>-5(ABBO( P+/>7>,4Q+M+(?(!-.,7+)(ABBC( Q(E)dE � F esc (t) 1 2 dE max dE E � t 1/2 dE 3 4 � R sh E � E -2 dE 2 � V s dt E -2 WI WITH NO CONNE TH NO CONNECTION CTION WI WITH TH THE INTRINSIC SPE THE INTRINSIC SPECTR CTRUM UM �
PROTON SPECTRUM AT EARTH � EVIDENCE FOR A CUTOFF! 9/(/!,+%.!E#+(/'B/!#(!/$G!533H!
SPECTRA
PREDICTED SPECTRUM PROTONS ONLY ALL PARTICLE Caprioli, PB & Amato 2009
SOME IMPLICATIONS 1. � PROTONS ARE EXPECTED TO BE ACCELERATED T0 ~10 6 GeV 2. � ACCELERATION IS Z DEPENDENT � E MAX (Z)=Z E MAX 3. � THE KNEE IS LIKELY TO BE THE RESULT OF OVERLAP ON THE MAX ENERGY OF EACH SPECIE 4. GALACTIC CRs SHOULD END WITH IRON @ ~10 17 eV ?
THE TRANSITION 1. � The SNR paradigm hints to a galactic cr spectrum ending at ~a few 10 17 eV 2. Observations also suggest the same trend DIP MIXED ANKLE
PROPAGATION OF PROTONS DIP P GZK 100 Mpc
MODIFICATION FACTOR Aloisio, Berezinsky, PB & Ostapchenko 2008
HOW DOES THE SPECTRUM LOOK LIKE? THE DIP Berezinsky et al. 2005 Aloisio et al. 2007
ACCIDENT OR PHYSICS? Berezinsky et al. 2005 Aloisio et al. 2007 ENERGY SHIFTS WITHIN SYSTEMATICS FOR ALL EXPS BUT Auger
HISTORICAL INTERPRETATION OF THE TRANSITION : THE ANKLE
ALTERNATIVE INTERPRETATION OF THE TRANSITION: MIXED COMPOSITION Allard et al. 2005-2008
UNDERSTANDING THE DIFFERENCE: � DIP VS MIXED From Kampert 2008 From Sokolsky, SoCoR Workshop
UNDERSTANDING THE DIFFERENCE: � DIP VS ANKLE DIP ANKLE LE Aloisio, Berezinsky, PB & Ostapchenko 2008
X MAX and RMS OF X MAX Auger HiRes
THE E GZK F FEATURE E HiR iRes Auger r From Roth (SoCOR Workshop)
CR Astronomy with PAO
SOME INCONSISTENCIES 1. � PAO hints to a gradually heavier composition @ high E 2. � …BUT THE GALACTIC B-FIELD � LARGE DEFLECTIONS 3. � WOULD THIS KEEP THE LARGE SCALE ANISOTROPY? 4. � EVEN MOST MIXED COMPOSITION MODELS DO PREDICT 5. � EVEN ASSUMING THAT WE ARE IN FACT SEEING HEAVY NUCLEI (THEREFORE NO CORRELATION) THEN THE FLUX SUPPRESSION IS NOT THE GZK FEATURE
SOM SOME CON E CONCLUSION ONS X-ray observations have probably provided us with the first evidence of b amplification This makes possible to reach the knee for protons Heavier nuclei follow with z The transition region would be naturally around 10 17 eV The competing models of the transition can be Discriminated through composition studies UHECRs remain confusing…
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