The origin of Cosmic Rays:New developments and old puzzles

K. Blum*, B. Katz*, A. Spector, E. WaxmanWeizmann Institute

*currently at IAS, Princeton

The cosmic ray spectrum

[From Helder et al., SSR 12]

Cosmic-ray E [GeV]

log [dJ/dE]

1 106 1010

E-2.7

E-3

Heavy Nuclei

Protons

Light Nuclei?

Galactic

UHEX-Galactic

[Blandford & Eichler, Phys. Rep. 87; Axford, ApJS 94; Nagano & Watson, Rev. Mod. Phys. 00; Lemoine, J. Phys. 13]

Source: Supernovae)?(

Source?Source?

Lighter

The cosmic ray generation spectrum

UHE (>109.5 GeV=101.5 EeV)

UHE: Composition

HiRes 2005

Auger 2010

HiRes 2010 (& TA 2011)

[Wilk & Wlodarczyk 10]*

[*Possible acceptable solution?, Auger collaboration 13]

UHE: Anisotropy & CompositionGalaxy density integrated to 75MpcCR intensity map (rsource~rgal)

[EW, Fisher & Piran 97]

Biased (rsource~rgal for rgal>rgal )

[Kashti & EW 08]

• Anisotropy @ 98% CL; Consistent with LSS

• Anisotropy of Z at 1019.7eV implies Stronger aniso. signal (due to p) at (1019.7/Z) eV

[since: Acceleration of Z(>>1) to E ~ Acceleration of p to E/Z, p(E/Z) propagation = Z(E) propagation, np >= nZ at the source.]

Not observed No high Z at 1019.7eV

[Kotera & Lemoine 08; Abraham et al. 08… Foteini et al. 11]

[Lemoine & EW 09]

[EW 1995; Bahcall & EW 03]

[Katz & EW 09]

• e2(dN/de)Observed=e2(dQ/de) teff. (teff. : p + gCMB N + p) Assume: p, dQ/de~(1+z)me-a

• >1019.3eV: consistent with protons, e2(dQ/de) =0.5(+-0.2) x 1044 erg/Mpc3 yr + GZK

UHE: Flux & Generation Spectrum

cteff [Mpc]GZK (CMB) suppression

log(e2dQ/de) [erg/Mpc2 yr]

Intermediate E (106 GeV=1 PeV < E < 101.5 EeV)

HE n: UHECR bound• p + g N + p p0 2g ; p+ e+ + ne + nm + nm

Identify UHECR sources Study BH accretion/acceleration physics

• For all known sources, tgp<=1:

• If X-G p’s:

Identify primaries, determine f(z)

3

2344

28

WB2

)1(,1)(for5,1

srscmGeV

yrerg/Mpc10/10

zzf

ddQddj

eee

en

nn [EW & Bahcall 99;

Bahcall & EW 01]

WB192 )eV10(

n

nn eeddj

[Berezinsky & Zatsepin 69]

Bound implications: n experiments

5.0yrerg/Mpc10

/344

2

ee ddQ

2 flavors,Fermi

IceCube (preliminary) detection• 28 events, compared to 12 expected, above 50TeV; ~4s (cutoff at 2PeV?)• 1/E2 spectrum, 4x10-8GeV/cm2s sr• Consistent with ne:nm:nt=1:1:1• Consistent with isotropy

[N. Whitehorn, IC collaboration, IPA 2013]

New era in n astronomy

IceCube (preliminary) detection

5.0yrerg/Mpc10

/344

2

ee ddQ

2 flavors,

IceCube’s detection: Some implications

• Unlikely Galactic: E2g~10-7(E0.1TeV)-0.7GeV/cm2s sr [Fermi]

~10-9(E0.1PeV)-0.7GeV/cm2s sr

• XG distribution of sources, e2(dQ/de) >=0.5x 1044 erg/Mpc3 yr @ 106GeV< E

<109GeV

• p, e2(dQ/de)PeV-EeV~ e2(dQ/de) >10EeV, tgp(pp)>~1 Or: e2(dQ/de)PeV-EeV>> e2(dQ/de) >10EeV, tgp(pp)<<1 &

Coincidence

Isotropic, 1:1:1 flavor ratio, E2n~4x10-8GeV/cm2s sr~E2WB @ 50TeV<E<2PeV

Low E (1GeV < E < 1TeV)

Estimating the G-CR production rate• CR production in the Galactic disk:

• Assuming CR production ~ SFR ~ SN rate, and using

we have

pp m

Znctnnn

Zc

Zff

dAdQcd

dn

)/()(

g/cmGeV10

7.8,g/cm102

GeV10104,1

seceff.prim.conf.ISM,eff.prim.sec

25.0

conf.ISMsec23

disk

5.03

disk

secconf.conf.

CR2

esse

etr

ee

e

3

7.023524

cmeV

GeV101.0yr,Mpc/105yr,kpc/10

Zddnn

dANd

SNSN e

ee

0.2-0.1yr,Mpc/ergGeV10

102 344CR2

ee

e

ZddQ

Galactic CR propagation models?• For all secondaries:

• For positrons:

At ~20GeV: frad~0.3~f10Be

• Predictions for e+ & p consistent with PAMELA & AMS observations.

• Positron anomalies? - Due to assumptions adopted RE

CR propagation.- Reflect the absence of a basic

principles model.

pp /

)/( eee

GeV10 GeV100

[Katz, Blum, Morag & EW 10; Blum Katz & EW 13]

-

)/(~)( secsec,sec, ZEEn ii s

rad,sec )/(~ fZEn s

radf

Primary e+ sources

DM annihilation [Hooper et al. 09] Pulsars [Kashiyama et al. 11]

The cosmic ray generation spectrum

XG CRs

XG n’sGalactic CRs(+ CRs~SFR)

Universal generation spectrum: Implications

• Natural: All CRs produced in galaxies, Rate ~ SFR [Loeb & EW 02; Parizot 05; Aublin et al.

05]

e2(dQ/de) =0.5(+-0.2) x 1044 erg/Mpc3 yr• If so, Galactic CR density << than average @

E>107GeV Transient sources, currently “dim state”

• Implications/ Consistency checks:- Etransient> EGalaxy(>107GeV CRs)~1050.5+-1.5erg, consistent with strong explosions (SNe, GRBs)- Starburst n emission

The 1020eV challenge

RB eBRBR

RBR

ccV p c

vcv

v/1~1 2

e

cec

BRL p22

2

v/21v

84

ep

p

v

v

sun122

20,

2

462

20

2

L10

erg/s10eV10/v

p

p

cL

e

e

2R

(tRF=R/c)

l =R/

/

2 2

[Lovelace 76; EW 95, 04; Norman et al. 95]

• GRB: 1019LSun, MBH~1Msun, M~1Msun/s, ~102.5

• AGN: 1014 LSun, MBH~109Msun, M~1Msun/yr, ~101

• MQ: 105 LSun, MBH~1Msun, M~10-8Msun/yr, ~100.5

Source physics challenges

Energy extraction

Jet acceleration

Jet content (kinetic/Poynting)

Particle acceleration

Radiation mechanisms

[Reviews: Lemoine 13; Kirk 08, 13]

[Reviws: GRBs Kouveliotou 94; Piran 05 AGN Begelman, Blandford & Rees 84 MQ HE: Aharonian et al 05; Khangulyan et al 07]

UHE: Bright transients• Electromagnetic acceleration in astrophysical sources

requires L>LB>1046 (2/) (e/Z 1020eV)2 erg/s No steady sources at d<dGZK Transient Sources

• If electrons are accelerated with protons, transients should also be bright in X-ray/g; The rate of such flares is much too low to account for the

CR flux unless L> >1050 erg/s

>1050 erg/s flares or

Inefficient e-acceleration (“dark flares”) [EW & Loeb 09]

[Lovelace 76; EW 95, 04; Norman et al. 95]

High energy n’s from Star Bursts• Starburst galaxies

– {Star formation rate, density, B} ~ 103x Milky way Most stars formed in z>1.5 star bursts

– CR e’s lose all energy to synchrotron radiation, CR p’s likely lose all energy to p production

- If p’s lose all energy & radio bgnd dominated by starbursts:

[Quataert et al. 06]

mmm nnnnmpp eepnpp ,

Synchrotron radio n

~(1GeV )calibration

[Loeb & EW 06]

Mark Westmoquette (University College London), Jay Gallagher (University of Wisconsin-Madison), Linda Smith (University College London), WIYN//NSF, NASA/ESA

Robert Gendler

M82 M81

[Loeb & EW 06]

Starburst galaxies: n emission

• Radio & n bgnd’s consistent with e2(dQ/de)~1044erg/Mpc3yr in galaxies, ~SFR, tgp(pp)>~1

Are SNRs the low E CR sources?

• UHE, Intermediate E: Not yet identified

• Low E- SuperNova Remnants? [Baade & Swicky 34]

So far, no clear evidence [ Gallant’s talk].

Electromagnetic observations- ambiguous(e.g. TeV e- I.C. [Katz & EW 08; Butt et al. 08]).

[e.g. Butt 09; Helder et al., SSR 12]

Summary• The identity of the CR source(s) is still debated.• Many open Q’s RE candidate source(s) physics

[accreting BHs].

• e2(dQ/de) ~ 1044erg/Mpc3yr at all energies. Suggests:

CRs of all E produced in galaxies @ a rate ~ SFR,

by transients releasing ~1050.5+-1.5erg.

• IceCube detects XG n’s, f~fWB at 50TeV—1PeV- A new era in n astronomy.- Consistent with the predictions of the ‘single

source’ hypothesis, for tgp(pp)>~1 in StarBursts.

A new era in HE n’s• IceCube’s sensitivity meets the minimum requirements for

detection of XG sources.• Preliminary detection of 50TeV-1PeV n’s.• Bright transients are the prime targets.• Coordinated wide field EM transient monitoring crucial: - Enhance n detection sensitivity, - Identify sources, Enable physics output.• XG n detection rate limited (<~10/yr).• Detection of a handful of n’s from EM identified sources

may resolve outstanding puzzles: - Identify UHECR (& G-CR) sources, - Resolve open “cosmic-accelerator” physics Q’s (related to BH-jet systems, particle acc., rad.

mechanisms), - Constrain n physics, LI, WEP.

Back up slides

Transient sources: GRB n’s• If: Baryonic jet

• Background free:

( )( ) 2GeV3.0// gee peV)10(eV10,eV1010,MeV1 165.14165.2 ng eee p

GRB/1001~ yr,km/yrerg/Mpc105.0

/eV102.05

10

eV10,2.0

2344

22/1

5.14b,

5.142

neee

ee

npmn

nnn

ddQfJ

WB

2.0ppf

[EW & Bahcall 97, 99; Rachen & Meszaros 98; Guetta et al. 01; Murase & Nagataki 06]

;skm/TeV1005.0

10~ 22

10

mn

EJ oA

TeV1005.2TeV1007.1

EE

IceCube’s limits

[Hummer, Baerwald, and Winter 12;

see also Li 12; He et al 12]

• IC40+59: No n’s for ~200 GRBs (~2 expected).• IC is achieving relevant sensitivity !• IC analyses overestimate GRB flux predictions,

and ignore astrophysical uncertainties:

G-XG Transition at ~1018eV?

@ 1018eV: Fine tuning

[Katz & EW 09]

Inconsistent spectrumG cutoff @ 1019eV

UHECR sources: Suspects• Constraints: - L>1012 (2/) Lsun , > 102.5 (L52)1/10 (t/10ms)-1/5

- e2(dQ/de) ~1043.7 erg/Mpc3 yr - d(1020eV)<dGZK~100Mpc !! No L>1012 Lsun at d<dGZK Transient Sources

• Gamma-ray Bursts (GRBs) Lg~ 1019LSun >1012 (2/) Lsun= 1017 (/ 102.5)2 Lsun

~ 102.5 (L52)1/10 (t/10ms)-1/5

e2(dQ/de)g ~ 1053erg*10-9.5/Mpc3 yr = 1043.5 erg/Mpc3 yr Transient: Tg~10s << Tpg ~105 yr

• Active Galactic Nuclei (AGN, Steady): ~ 101 L>1014 LSun= few brightest !! Non at d<dGZK Invoke: * “Hidden” (proton only) AGN * L~ 1014 LSun , t~1month flares If e- accelerated: X/g observations rare L>1017Lsun

[Blandford 76; Lovelace 76]

[EW 95, Vietri 95, Milgrom & Usov 95]

[EW 95]

[Boldt & Loewenstein 00][Farrar & Gruzinov 08]

[EW & Loeb 09]

Bound implications: I. AGN n models

BBR05

“Hidden” (n only) sources

Violating UHECR bound

Single flavor Multi flavor

[Anchordoqui & Montaruli 09]

(Correct) detailed CR propagation models must agree with simple, analytic results

derived from sec• Example: Diffusion models with {D~K0 e, box height L} reproduce data for parameter combinations shown in fig. [Maurin et al. 01]

• Trivial explanation: [Katz, Blum & EW 09]Require sec(e =35GeV) to agree with the value inferred from B/C sec =[3.2,3.45,3.9] g/cm2

[green, blue, red]