The origin of Cosmic Rays: New developments and old puzzles K. Blum*, B. Katz*, A. Spector, E. Waxman Weizmann Institute *currently at IAS, Princeton

The cosmic ray spectrum [From Helder et al., SSR 12]

Cosmic-ray E [GeV] log [dJ/dE] E -2.7 E -3 Heavy Nuclei Protons Light Nuclei? Galactic UHE X-Galactic [Blandford & Eichler, Phys. Rep. 87; Axford, ApJS 94; Nagano & Watson, Rev. Mod. Phys. 00; Lemoine, J. Phys. 13] Source: Supernovae(?) Source? Lighter

The cosmic ray generation spectrum

UHE (> GeV= EeV)

UHE: Composition HiRes 2005 Auger 2010 HiRes 2010 (& TA 2011) [Wilk & Wlodarczyk 10]* [*Possible acceptable solution?, Auger collaboration 13]

UHE: Anisotropy & Composition Galaxy density integrated to 75Mpc CR intensity map (  source ~  gal ) [EW, Fisher & Piran 97] Biased (  source ~  gal for  gal >  gal ) [Kashti & EW 08] 98% CL; Consistent with LSS Anisotropy of Z at eV implies Stronger aniso. signal (due to p) at ( /Z) eV [ since: Acceleration of Z(>>1) to E ~ Acceleration of p to E/Z, p(E/Z) propagation = Z(E) propagation, n p >= n Z at the source.] Not observed  No high Z at eV [Kotera & Lemoine 08; Abraham et al. 08… Foteini et al. 11] [Lemoine & EW 09]

[EW 1995; Bahcall & EW 03] [Katz & EW 09]  2 (dN/d  ) Observed =  2 (dQ/d  ) t eff. (t eff. : p +  CMB  N +  Assume: p, dQ/d  ~(1+z) m  -  > eV: consistent with protons,  2 (dQ/d  ) =0.5(+-0.2) x erg/Mpc 3 yr + GZK UHE: Flux & Generation Spectrum ct eff [Mpc] GZK (CMB) suppression log(  2 dQ/d  ) [erg/Mpc 2 yr]

Intermediate E (10 6 GeV=1 PeV < E < EeV)

HE  : UHECR bound p +   N +   0  2  ;  +  e + + e +  +   Identify UHECR sources Study BH accretion/acceleration physics For all known sources,   p <=1: If X-G p ’ s:  Identify primaries, determine f(z) [EW & Bahcall 99; Bahcall & EW 01] [Berezinsky & Zatsepin 69]

Bound implications: experiments 2 flavors, Fermi

IceCube (preliminary) detection 28 events, compared to 12 expected, above 50TeV; ~4  (cutoff at 2PeV?) 1/E 2 spectrum, 4x10 -8 GeV/cm 2 s sr Consistent with e :  :  =1:1:1 Consistent with isotropy [N. Whitehorn, IC collaboration, IPA 2013] New era in astronomy

IceCube (preliminary) detection 2 flavors,

IceCube’s detection: Some implications Unlikely Galactic: E 2   ~10 -7 (E 0.1TeV ) -0.7 GeV/cm 2 s sr [Fermi]  ~10 -9 (E 0.1PeV ) -0.7 GeV/cm 2 s sr XG distribution of sources,  2 (dQ/d  ) >=0.5x erg/Mpc GeV< E <10 9 GeV p,  2 (dQ/d  ) PeV-EeV ~  2 (dQ/d  ) >10EeV,   p(pp) >~1  Or:  2 (dQ/d  ) PeV-EeV >>  2 (dQ/d  ) >10EeV,   p(pp) <<1 & Coincidence Isotropic, 1:1:1 flavor ratio, E 2  ~4x10 -8 GeV/cm 2 s sr~E 2  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

Galactic CR propagation models? For all secondaries: For positrons: At ~20GeV: f rad ~0.3~f 10 Be 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. [Katz, Blum, Morag & EW 10; Blum Katz & EW 13] -

Primary e+ sources DM annihilation [Hooper et al. 09] Pulsars [Kashiyama et al. 11]

The cosmic ray generation spectrum XG CRs XG ’s Galactic CRs (+ CRs~SFR)

Universal generation spectrum: Implications Natural: All CRs produced in galaxies, Rate ~ SFR [Loeb & EW 02; Parizot 05; Aublin et al. 05]   2 (dQ/d  ) =0.5(+-0.2) x erg/Mpc 3 yr If so, Galactic CR density 10 7 GeV  Transient sources, currently “dim state” Implications/ Consistency checks: - E transient > E Galaxy (>10 7 GeV CRs)~ erg, consistent with strong explosions (SNe, GRBs) - Starburst emission

The eV challenge R B v v 2R  t RF =R/  c) l =R/   22 22 [Lovelace 76; EW 95, 04; Norman et al. 95]

GRB: L Sun, M BH ~1M sun, M~1M sun /s,  ~ AGN: L Sun, M BH ~10 9 M sun, M~1M sun /yr,  ~10 1 MQ: 10 5 L Sun, M BH ~1M sun, M~10 -8 M sun /yr,  ~ 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>L B >10 46 (  2 /  ) (  /Z eV) 2 erg/s  No steady sources at d<d GZK  Transient Sources If electrons are accelerated with protons, transients should also be bright in X-ray/  The rate of such flares is much too low to account for the CR flux unless L> >10 50 erg/s  >10 50 erg/s flares or Inefficient e-acceleration (“dark flares”) [EW & Loeb 09] [Lovelace 76; EW 95, 04; Norman et al. 95]

High energy ’s from Star Bursts Starburst galaxies –{Star formation rate, density, B} ~ 10 3 x 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  production - If p’s lose all energy & radio bgnd dominated by starbursts: [Quataert et al. 06] Synchrotron radio  (~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: emission Radio & bgnd’s consistent with  2 (dQ/d  )~10 44 erg/Mpc 3 yr in galaxies, ~SFR,   p(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].  2 (dQ/d  ) ~ erg/Mpc 3 yr at all energies. Suggests: CRs of all E produced in a rate ~ SFR, by transients releasing ~ erg. IceCube detects XG n’s,  ~  WB at 50TeV—1PeV - A new era in astronomy. - Consistent with the predictions of the ‘single source’ hypothesis, for   p(pp) >~1 in StarBursts.

A new era in HE ’ s IceCube ’ s sensitivity meets the minimum requirements for detection of XG sources. Preliminary detection of 50TeV-1PeV ’s. Bright transients are the prime targets. Coordinated wide field EM transient monitoring crucial: - Enhance detection sensitivity, - Identify sources, Enable physics output. XG detection rate limited (<~10/yr). Detection of a handful of ’ 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 physics, LI, WEP.

Back up slides

Transient sources: GRB ’ s If: Baryonic jet Background free: [EW & Bahcall 97, 99; Rachen & Meszaros 98; Guetta et al. 01; Murase & Nagataki 06]

IceCube’s limits [Hummer, Baerwald, and Winter 12; see also Li 12; He et al 12] IC40+59: No ’ 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 ~ eV: Fine tuning [Katz & EW 09] Inconsistent spectrumG eV

UHECR sources: Suspects Constraints: - L>10 12 (  2 /  ) L sun,  > (L 52 ) 1/10 (  t/10ms) -1/5 -  2 (dQ/d  ) ~ erg/Mpc 3 yr - d(10 20 eV)<d GZK ~100Mpc !! No L>10 12 L sun at d<d GZK  Transient Sources Gamma-ray Bursts (GRBs)  L  ~ L Sun >10 12 (  2 /  ) L sun = (  / ) 2 L sun   ~ (L 52 ) 1/10 (  t/10ms) -1/5  2 (dQ/d  )  ~ erg* /Mpc 3 yr = erg/Mpc 3 yr Transient:  T  ~10s <<  T p  ~10 5 yr Active Galactic Nuclei (AGN, Steady):  ~ 10 1  L>10 14 L Sun = few brightest !! Non at d<d GZK  Invoke: * “ Hidden ” (proton only) AGN * L~ L Sun,  t~1month flares If e - accelerated: X/  observations  rare L>10 17 L sun [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 models BBR05 “Hidden” ( 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~K 0  , box height L} reproduce data for parameter combinations shown in fig. [Maurin et al. 01] Trivial explanation: [Katz, Blum & EW 09] Require  sec (  =35GeV) to agree with the value inferred from B/C  sec =[3.2,3.45,3.9] g/cm 2 [green, blue, red]