Transcript
Page 1: E. Waxman Weizmann Institute

The beginning of extra-galactic neutrino astronomy:

What have we learned from IceCube’s neutrinos?E. Waxman

Weizmann Institute

arXiv:1312.0558arXiv:1311.0287

J. Bahcall, “Neutrino Astronomy” (1989): “The title is more of anexpression of hope than a description of the book’s content…”

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The main driver of HE n astronomy: The origin of CRs

Cosmic-ray E [GeV]

log [dJ/dE]

1 106 1010

E-2.7

E-3

Heavy Nuclei

Protons

Light Nuclei?

Galactic

UHEX-GalacticSource: Supernovae)?(

Source?

Source?Lighter

Where is the G/XG transition?

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Consider the rate of CR energy production at

UHE, >1010 GeV;Intermediate E, 1-100 PeV;“Low” E, ~10 GeV.

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UHE: Composition

HiRes 2005

Auger 2010

HiRes 2010 (& TA 2011)

[Wilk & Wlodarczyk 10]*

[*Possible acceptable solution?, Auger collaboration 13]

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UHE: Energy production rate & spectrum Protons

dQ/d log e =Const. =0.5(+-0.2) x 1044 erg/Mpc3 yr

Mixed compositioncteff [Mpc]

log(dQ/d log e) [erg/Mpc3 yr]

[Katz & EW 09] [Allard 12]

GZK

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Collisionless shock acceleration• The only predictive model.

• No complete basic principles theory, but - Test particle + elastic scattering assumptions gives v/c<<1: dQ/d log e=Const., v/c~1: dQ/d log e=Const.xe-2/9 (G>>1, isotropic scattering),

- Supported by basic principles plasma simulations,

- dQ/d log e=Const Observed in a wide range of sources (lower energy p’s in the Galaxy, radiation emission from accelerated e-).

[Krimsky 77]

[Keshet & EW 05]

[Spitkovsky 06, Sironi & Spitkovsky 09, Keshet et al. 09, …]

200c/wp

40c/wp

Lp

thermalL Rc

R ,)(

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Intermediate energy: Neutrinos

• 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

23448

WB2

)1(,1)(for5,1

srscm

GeV

yrerg/Mpc10

log/10

zzf

ddQ

d

dj

[EW & Bahcall 99;

Bahcall & EW 01]

WB192 )eV10(

d

dj[Berezinsky & Zatsepin 69]

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BBR05

“Hidden” (n only) sources

Violating UHECR bound

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Bound implications: >1Gton detector

5.0yrerg/Mpc10

log/344

ddQ

2 flavors,Fermi

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e2Fn =(2.85+-0.9)x10-8GeV/cm2sr s =e2FWB= 3.4x10-8GeV/cm2sr s Consistent with Isotropy and with ne:nm:nt=1:1:1 (p deacy + cosmological prop.).

IceCube: 37 events at 50Tev-2PeV ~6s above atmo. bgnd. [02Sep14 PRL]

A new era in n astronomy

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IceCube’s detection: Implications

• Unlikely Galactic: Isotropy, and e2Fg~10-7(E0.1TeV)-0.7GeV/cm2s sr [Fermi]

e2Fn ~10-9(E0.1PeV)-0.7GeV/cm2s sr << FWB

• DM decay? The coincidence of 50TeV<E<2PeV n flux, spectrum (& flavor) with the WB bound is unlikely a chance coincidence.

• XG distribution of sources, (dQ/d log e)PeV-EeV~ (dQ/d log e) >10EeV, tgp(pp)>~1 [“Calorimeters”] Or (dQ/d log e)PeV-EeV>> (dQ/d log e) >10EeV, tgp(pp)<<1 & Coincidence over a wide energy range.

• (dQ/d log e) ~ e0 implies: p, G-XG transition at ~1019eV.

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Candidate CR calorimeters: Starburst galaxies

• Candidate UHECR sources are NOT expected to be “calorimeters” for <100PeV p’s [e.g. Murase et al. 2014].

• Radio, IR & g-ray (GeV-TeV) observations Starbursts are calorimeters for E/Z reaching (at least) 10PeV.• Most of the stars in the universe were formed in Starbursts.

• If CR sources reside in galaxies and Q~Star Formation Rate (SFR), Then Fn(en<1PeV)~FWB .

• (And also a significant fraction of

the g-bgnd, see Irene’s talk).

[Loeb & EW 06]

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Low Energy, ~10GeV

• Our Galaxy- using “grammage”

• Starbursts- using radio to g observations

Q/SFR similar for different galaxy types, dQ/dlog e ~Const. at all e!

0.2-0.1yr,Mpc/ergGeV10

102~log

344

Zd

dQ

yrMpc/erg102)0 GeV,10~(log

344zd

dQ

[Katz, EW, Thompson & Loeb 14]

0

Galaxy

Galaxy /log/

log zVSFRSFR

ddQ

d

dQ

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The cosmic ray spectrum

[From Helder et al., SSR 12]

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The cosmic ray generation spectrum

XG CRs

XG n’sMW CRs,Starbursts(+ CRs~SFR)

[Katz, EW, Thompson & Loeb 14]

A single source?

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• Electromagnetic acceleration in astrophysical sources requires L> 1014 LSun

(G2/b) (e/Z 1020eV)2 erg/s

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

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

• No steady sources at d<dGZK Transient Sources (AGN flares?),

Charged CRs delayed compared to g’s.

Source candidates & physics challenges

Energy extraction;Jet acceleration andcontent (kinetic/Poynting)

Particle acceleration,Radiation mechanisms

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

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Identifying the sources

• IC’s n’s are produced by the “calorimeters” surrounding the sources.

• DQ~1deg Identification by angular distribution impossible.

• Our only hope: Identification of transient sources by temporal - n gassociation.

• Requires: Wide field EM monitoring, Real time alerts for follow-up of high E n events, and Significant increase of the n detector mass at ~100TeV [Fn(source) may be << Fn(calorimeter)~FWB [ e.g. Fn(GRB) ~0.1

FWB]].

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What will we learn from - n gassociations?

• Identify the CR sources.Resolve key open Qs in the accelerators’ physics

(BH jets, particle acceleration, collisionless shocks).

• Study fundamental/n physics: - p decay ne:nm:nt = 1:2:0 (Osc.) ne:nm:nt = 1:1:1 t appearance, - GRBs: n-g timing (10s over Hubble distance) LI to 1:1016; WEP to 1:106 .

• Optimistically (>100’s of n’s with flavor identification): Constrain dCP, new phys.

[Learned & Pakvasa 95; EW & Bahcall 97]

[EW & Bahcall 97; Amelino-Camelia,et al.98; Coleman &.Glashow 99; Jacob & Piran 07]

[Blum, Nir & EW 05; Winter 10; Pakvasa 10;… Ng & Beacom 14; Ioka & Murase 14;

Ibe & Kaneta 14; Blum, Hook & Murase 14]

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Summary

• IceCube detects extra-Galactic n’s. Fn=FWB at 50TeV-2PeV.

• Flux & spectrum of ~1010GeV CRs, ~1PeV n (and ~10 GeV CRs)

Consistent with CR p sources in galaxies, dQ/dlog e~Const., Q~SFR. * IceCube’s detection consistent with the predicted Fn(en<1PeV)~FWB

from sources residing in starbursts. [A flurry of models post-dicting IceCube’s results by arbitrarily choosing model parameters to match the flux.]

* A single type of sources?

• The sources are unknown. * UHE: L>1047(50)erg/s, GRBs or bright (to be detected) AGN flares.• Temporal -n g association is key to:

CR sources identification, Cosmic accelerators’ physics, Fundamental/n physics.

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What is required for the next stageof the n astronomy revolution

• The number of events provided by IceCube (~1/yr @ E>1 PeV, ~10/yr @ E>0.1PeV) will not be sufficient for an accurate determination of spectrum, flavor ratio and (an)isotropy. n telescopes Meff(100TeV) expansion to ~10Gton (IceCube, Km3Net).

• Wide field EM monitoring.

• Adequate sensitivity for detecting the ~1010GeV GZK n’s.

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Backup Slides

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UHE, >1010GeV, CRs

3,000 km2

J(>1011GeV)~1 / 100 km2 year 2p sr

Ground array

Fluorescence detector

Auger:3000 km2

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Where is the G-XG transition?

@ E<1018eV ?

• Fine tuning• Inconsistent with Fermi’s XG g (<1TeV) flux

e2(dQ/de) =Const @ E~1019eV

[Katz & EW 09]

[Gelmini 11]

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UHE: Do we learn from (an)isotropy?

Galaxy 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 Not observed No high Z at 1019.7eV

[Kotera & Lemoine 08; Abraham et al. 08… Oikonomou et al. 13]

[Lemoine & EW 09]

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p production: p/A—p/g

• p decay ne:nm:nt = 1:2:0 (propagation) ne:nm:nt = 1:1:1

• p(A)-p: en/ep~1/(2x3x4)~0.04 (epeA/A);

- IR photo dissociation of A does not modify G; - Comparable particle/anti-particle content.

• p(A)-g: en/ep~ (0.1—0.5)x(1/4)~0.05;

- Requires intense radiation at eg>A keV;

- Comparable particle/anti-particle content, ne excess if dominated by D resonance (dlog

ng/dlog eg<-1).

[Spector, EW & Loeb 14]

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IceCube’s GRB limits

[Hummer, Baerwald, and Winter 12;

see also Li 12; He et al 12]

• No n’s associated with ~200 GRBs (~2 expected). • IC analyses overestimate GRB flux predictions, and ignore model uncertainties.• IC is achieving relevant sensitivity.

WBGRB

2

1

,,

2.0

1PeVTeVMeV1

5005.2

b

b

[EW & Bahcall 97]

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Are SNRs the low E CR sources?

• So far, no clear evidence. Electromagnetic observations- ambiguous.

E.g.: “p decay signature” [Ackermann et al. 13]:


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