Cosmic-ray Reservoirs as
Multi-Messenger Sources“reservoir”
Kohta Murase (Penn State)
July 25 2016 @ Chiba Univ.

HE Neutrino Astrophysics Started
Origins and mechanism of cosmic neutrinos?
-pp or pγ? -connection to UHECRs? -connection
to γ rays? – new physics?
90o
Coma
Virgo

37
9

DM

23

25
%

50

DM

%

31

Galactic Plane

180o

24
25

complied from IceCube 14 PRL

3

27

5

-180o

2

22

15
12

30

LMC
19

Nort

1

6

4

35

hern

Andromeda

Hem
Sout
isph
hern
ere
Hem
isph
ere

34

11

Ophiuchus
14

33

26

8

36

29

13

Perseus

16

17

SMC

Fornax

18
21

20

7
10

Galactic-90o

No single source detection & no significant clustering
Easy to see: mostly isotropic → extragalactic sources(supported by diffuse gamma-ray searches:
KM, Ahlers & Lacki 13 PRDR, Ahlers & KM 14 PRD)′b
E ν ≈ 0.05(0.5mpc2 ε̄∆ /E ′ )Motivation:
CosmicRays–
A
CenturyOld
Puzzle−3tinj /2 Gyr)dNCR
∝ E −sCR
2 kneedE~100 PeV(tint /2 Gyr)
nd

LHC

E-2.7

s1/2=2x7 TeV

knee~3 PeV

Galactic

Open problems- How is the spectrum formed?
(ex. transition to extragalactic)- How are CRs accelerated?
(ex. Fermi mechanism: sCR~2)- How do CRs propagate?
…

ankle~3 EeV
supernova
remnants?

E-2.6
extragalactic

PeV=1015 eV
GeV

TeV

EeV

ZeV

The key question“What is the origin?”
extreme energy (EeV-ZeV)→ extreme sourcesastrophysical source(GRB, AGN etc.)

Multi-Messenger Approachhigh-energyggy γ
cosmic background radiation(low-energy γ)

extragalactic
galaxyintergalacticmagnetic fieldγνintergalactic space
Milky Way

CR

Earth

Astrophysical “Isotropic” Neutrino Background – Mean Diffuse Intensity

diffuse ν intensity of extragalactic sources (cf. supernova ν bkg.) ← consistent w. isotropic distribution# #"εν2 qν(εν): ν emissivity at z=0##
dt # 2c2physics”#
dz # # εν qν (εν )F (z)(4)“sourceε ν Φν =qν=Lx(source density)
4πdzqν=Εx(burst rate)
F(z): redshift evolutiontz=0 (present)
2
3 GMnsEB ≈∼ 3 × 1053 erg
5 Rns

(5)

z=1

F(z)

typically maximum at z~1-2
ex. star-formation rate
supernova rate
AGN density

d~3 Gpc
z=5
d~8 Gpcz

Most contributions come from unresolved distant sources, difficult to see each

PACS numbers: 98.70.Rz, 11.30.Cp, 98
1/2

eﬀ
fpγ ≈ n̂BL σpγrBLR ≃ 5.4 × 10−2 LAD,46.5

Cosmic-Ray Connection: Hint or Conspiracy?
c2
ε ν Φν =4π"# ## dt # 2
dz ## ## εν qν (εν )F (z)dz(4)
Eν2 Φν ≈E2  [GeV cm-2 s-1 sr-1]

10-5

5 Rns

∼ 3 × 10erg"
fmes 2
εp qp (εp ) fz
4−282

σpγ = κpγ σpγ ∼ 10cm
fmes (<1): meson production
efficiency (ex. fpγ~0.2nγσpγΔ)fz (~0.6-5): source redshift evolution# dzratedtper volume
εp2 q(εp): CR energy generation| dz|qeﬀ p (z)Aγ ≈ nγ σAγ ∆
44
-3
-1 f1+z2
2
3 GM
obs. UHECR
flux:)=0.6x10
ns εp q(εp53

EB ≈

ctH
4π
eﬀ

eﬀ
f!pγ ≈ nγ σpγ∆

erg Mpcfz =yr & ftmesq →1 limit(5)
H p(Waxman & Bahcall 98 PRD)

IceCube 2015

1/2

eﬀ
eﬀ ≃ 5.4 × 10−2 L
fpγ ≈ n̂BL σpγ
rσ
10−27 cm2
BLR
Aγ = κAγ σAγ ∼ AD,46.5−1make a ν-CR connection
Attempts to

10-6

13
7
30(r/10have
cm)
!
(B/G)
!
10
(Γ /10been made but may not be easyj
eﬀfpγ ≈ nγ σpγ∆

10-7

Waxman-Bahcall (s=2.0)

10-8
10

τγγ ≈ nγ14,(0.1σT )∆(Katz et al. 13, Kistler+
Yoshida & Takami 14, KM & Waxman 16)
1/2

eﬀ
fpγ ≈ n̂BL σpγrBLR ≃ 5.4 × 10−2 LAD,46.5
eﬀ
σpγ= κpγ σpγ ∼ 10−28 cm2

2
ε
Φν =
Nucleus-Survival (s=2.3) ν%%

0.1σγγτγγ ≈ %%eﬀdt f%%pγ ∼2 10fpγ
σ
dz
ε
pγ
eﬀ
ν qν (εν )F (z)c% dz %
fpγ ≈ nγ σpγ ∆4πeﬀ$← “nucleus-survival”
boundsfAγ ≈ nγ σAγ ∆-9(KM & Beacomfpγ
10!PRD)
0.01
eﬀ
σpγ= κpγ σpγ ∼ 10−28 cm2

10-10 4
10

5

10

6

10
E [GeV]eﬀ
σAγ= κAγ σAγ ∼ 10−27 cm2

Phys. Rev. Lett.
103, 081102 (200910[1] K. Murase,10f ≈ (σ eﬀ /σ eﬀ )f " 0.178pγn σ eﬀ pγ
fAγ ≈γ Aγ ∆AγAγ

Astrophysical Extragalactic Scenarios
Cosmic-ray Accelerators(ex. UHECR candidate sources)
Active galactic nuclei

γ-ray burst

accretion tomassive black holecore-collapse of
massive stars- γ-ray bursts
ex. Waxman & Bahcall 97, KM et al. 06
after Neutrino 2012:
Cholis & Hooper 13, Liu & Wang 13
KM & Ioka 13, Winter 13, Senno, KM & Meszaros 16- Active galactic nuclei
ex. Stecker et al. 91, Mannheim 95
after Neutrino 2012:
Kalashev, Kusenko & Essey 13, Stecker 13,
KM, Inoue & Dermer 14, Dermer, KM & Inoue 14,
Tavecchio et al. 14, Kimura, KM & Toma 15,
Padvani et al. 15, Wang & Li 16

Cosmic-ray Reservoirs
Starburst galaxy

Galaxy group/cluster

high star-formation→ many supernovae

gigantic reservoirs w.
AGN, galaxy mergers- Starburst galaxies (not Milky-Way-like)ex. Loeb & Waxman 06, Thompson et al. 07
after Neutrino 2012:
KM, Ahlers & Lacki 13, Katz et al. 13,
Liu et al. 14, Tamborra, Ando & KM 14,
Anchordoqui et al. 14, Senno et al. 15- Galaxy groups/clusters
ex. Berezinsky et al. 97, KM et al. 08, Kotera et al. 09
after Neutrino 2012:
KM, Ahlers & Lacki 13, Fang & Olinto 16

Astrophysical Extragalactic Scenarios
Cosmic-ray Accelerators(ex. UHECR candidate sources)
Active galactic nuclei

γ-ray burst

accretion tomassive black holecore-collapse of
massive stars

Cosmic-ray Reservoirs

p + γ → Nπ + X
σpγ

Starburst galaxy

Galaxy group/cluster

high star-formation→ many supernovae

gigantic reservoirs w.
AGN, galaxy mergers

p + p → Nπ + X
σpproughly energy-independent

Δ-resonance(+ direct ch.)σpγ~ασpp~0.5 mb
ε'pε’γ ~ (0.34 GeV)(mp/2) ~ 0.16 GeV2

σpp~1/mπ2~30 mb

Astrophysical Extragalactic Scenarios
Cosmic-ray Accelerators(ex. UHECR candidate sources)
Active galactic nuclei

γ-ray burst

accretion tomassive black holecore-collapse of
massive stars

Cosmic-ray Reservoirs
Starburst galaxy

Galaxy group/cluster

high star-formation→ many supernovae

gigantic reservoirs w.
AGN, galaxy mergers

p + γ → Nπ + X
E2 Φ

p + p → Nπ + X

CRobs. photon spectra& source sizegas density &source sizeCRν

ν
0.1 TeV

Φ∝E-s

E2 Φ

sν≠sCR
PeV

sν~sCR
0.1 TeV

Eν

PeV
Eν

Eν ~ 0.04 Ep: PeV neutrino ⇔ 20-30 PeV CR nucleon energy

Astrophysical Extragalactic Scenarios
Cosmic-ray Accelerators(ex. UHECR candidate sources)
Active galactic nuclei

γ-ray burst

accretion tomassive black holecore-collapse of
massive stars

Cosmic-ray Reservoirs
Starburst galaxy

Galaxy group/cluster

high star-formation→ many supernovae

gigantic reservoirs w.
AGN, galaxy mergers

p + γ → Nπ + X
E2 Φ

p + p → Nπ + X
E2 Φ

CR

obs. photon spectra& source sizegas density &source sizeν

ν
0.1 TeVCRsν≠sCR
PeV

sν~sCR
0.1 TeV

Eν

PeV
Eν

Eν ~ 0.04 Ep: PeV neutrino ⇔ 20-30 PeV CR nucleon energy

Cosmic-Ray Accelerators
Active galactic nuclei

γ-ray burst

relativistic
outflow

accretion tomassive black holecore-collapse of
massive stars

ex. shocks in outflows→ electron acceleration→ radiation (ex. synchrotron)

γ
e+

CR e

target γ

νe

π+

CR p

ν

νµ

µ+

en
νe

νµ
p

CR?

CRs may or may not escapeHE Neutrinos from Classical GRBs
Standard jet models as the cosmic ν origin: excluded by multimessenger obs.
- Classical GRBs: constrained by stacking analyses <~ 10-9 GeV cm-2 s-1 sr-1
※ space- and time-coincidence (duration~30 s → background free)

10

-9

10-10

γ

!"#$

E2 φν(ν)[GeV cm-2s-1sr-1]

10-8

10-11

105

10
!"#$
E [GeV]6

R=1012cm
R=1013cm
R=1014cm
R=1015cm
R=1016cm

10-9

IC-40/59(IC-79/86 stronger)

10-10

10-11

ν

10-12

IceCube 2015

10-8

The IceCube Collaboration
Modified Guetta et al. (2004)
Modified analytic result
Numerical result
Spectra for indivadual GRB

E2 φν(ν)[GeV cm-2s-1sr-1]

CR

ν

Classical GRBs (prompt)
He et al.

γ

The Astrophysical Journal, 752:29 (10pp), 2012 June 10107νFigure 2. Neutrino
spectra numericallyby adopting
the internalComm.
shock
Bustamante,
Baerwald,
KM,calculated& Winter
15 Nature
2 obradius R = 2Γ ctv /(1 + z) for 215 GRBs (light red lines) observed during
the IceCube operations in the 40-string and 59-string configurations. We use the

10-12
104

105

106

107

108

109

1010

Eν [GeV]Figure 3. Spectra of the total neutrino emission produced by 215 GRBs,
He+ KM 12 ApJ
assuming the same dissipation radius for every GRB at R = 1012 cm (the13black solid line), R = 10 cm (the blue solid line), R = 1014 cm (the green
solid line), R = 1015 cm (the yellow solid line), and R = 1016 cm (the red

HE Neutrinos from AGN Jets
Standard jet models as the cosmic ν origin: disfavored by multimessenger obs.
- Blazars: 1. obs. SEDs (int. & ext.) → hard spectral shape (KM, Inoue & Dermer 14)
2. no clustering (KM & Waxman 16) 3. no source association (IceCube Coll. 15)
Blazars10-5

    

   

KM, Inoue & Dermer 14    

E2 Φ [GeV cm-2 s-1 sr-1]




10-6

Standard diffuse ν predictions
HZ97 (Blazar)
MPERS03 (LBL)
MPERS03 (HBL)
PPGR15 (BL Lac)
MID14 (Blazar w. ξcr=3)
MID14 (Blazar w. ξcr=50)

ruled outby IceCube(6-yr EHE)

10-7

10-8

10

-9

10

IC-79/86
4prelim. 5
10106
E [GeV]

107

108- Very hard spectra: a general trend of one-zone models- Many of them (including a leptonic-hadronic model) are excluded by IceCube

No significant excess
Controversy: Blazars as the Origin of IceCube’s Neutrinos?
X The smallest p-value is 6% for the "All 2LAC Blazar"
X

Upperlimits
IceCube on
15 diffuse flux contribution assuming parameterization in ApJ 720:435 (2010)

NO! (IceCube 15, Wang & Li 15, KM & Waxman 16)- Comparison w. FSRQs’ γ-ray bkg. (Ajello+ 13 ApJ)
→ average ratio: Lν/Lγ~0.1 (for all-flavor Lν)- Blazars are rare objects in the Universe
Lγ/Lν~0.1 → nearby blazars should be seen
but unobserved- Some model-dependence but quite reasonable(e.g., power-law assumption,
γ-dim population of blazars)

All 2LAC

F100 300000 MeV [10 6 cm 2 s 1 ]IceCube Diffuse flux

2010 2010.5
2.5
22011 2011.5

2012 2012.5

2013 2013.5

Krauss+ 15
Nature Phys.
big bird (2 PeV)

1.5

Figure 14 Event display showing Big Bird, with 378 optical modules hit. Each sphere showsa hit optical module. The size of the spheres shows the number of photoelectrons observed by
the DOM, while the color indicates the time, with red being earliest, and blue latest. Figure
courtesy of the IceCube Collaboration.

1

rays, including the watershed discoveries of antimatter, the pion, the muon, the kaon, andseveral other particles. In this article, we have both reviewed the nascent field of cosmic
neutrino astronomy and considered some of the potential ways CR science will once again
point the way in the quest to understand Nature at its most fundamental.
Acknowledgments
We would like to thank Francis Halzen, Stephen King, Soeb Razzaque, and the IceCube
Collaboration for allowing us to use various figures from their papers in this review. LAA is
supported by U.S. National Science Foundation (NSF) CAREER Award PHY1053663 and by
the National Aeronautics and Space Administration (NASA) Grant No. NNX13AH52G. VB
is supported by the U. S. Department of Energy (DoE) Grant No. DE-FG-02- 95ER40896.
IC and DH are supported by DoE. HG is supported by NSF Grant No. PHY-0757959. AK is
supported by DoE Grant No. de-sc0009937 and by the World Premier International Research

0.5

52

0
55200

55400

55600

55800 56000
MJD

56200

56400

56600

YES! (Padovani & Resconi 14, Krauss+ 15)- Three PeV events may be associated with
distant blazars- Low significance(~2σ association of the 2 PeV event w. a FSRQ )- Association w. a HESE event can be explained
if Lγ~LνAstrophysical Extragalactic Scenarios
Cosmic-ray Accelerators(ex. UHECR candidate sources)
Active galactic nuclei

γ-ray burst

accretion tomassive black holecore-collapse of
massive stars

Cosmic-ray Reservoirs
Starburst galaxy

Galaxy group/cluster

high star-formation→ many supernovae

gigantic reservoirs w.
AGN, galaxy mergers

p + γ → Nπ + X
E2 Φ

p + p → Nπ + X

CRobs. photon spectra& source sizegas density &source sizeCRν

ν
0.1 TeV

Φ∝E-s

E2 Φ

sν≠sCR
PeV

sν~sCR
0.1 TeV

Eν

PeV
Eν

Eν ~ 0.04 Ep: PeV neutrino ⇔ 20-30 PeV CR nucleon energy

Cosmic-Ray Reservoirs
Starburst galaxies

kpc

Galaxy clusters/groups“cosmic-ray
reservoirs”

B~0.1-1 mGsupernovae
γ-ray bursts
active galaxies

Mpc

B~0.1-1 µG
galaxies
active galaxies
galaxy mergers
accretion shockse+µ+target gas

νµ

π+

νe

CR p
e-

νµ

n
p

ν, γ

νe

CR confinement

CR

Loeb & Waxman 06
KM, Inoue & Nagataki 08

low-energy CRs are
confined by magnetic fields

magnetized region w. CR sources

sufficiently high-energy CRs
escape without interactions

Points of CR Reservoir Models• Some contributions must exist: very natural(galaxies contain CRs & gamma rays are detected)• Predicted before IceCube’s discovery(a multi-PeV break/cutoff has been expected)(Berezinsky et al. 97, Loeb & Waxman 06, KM et al. 08 ApJ, Kotera, Allard, KM et al. 09)• “Unification” of multi-messengers is possible(KM, Ahlers & Lacki 13, Katz et al. 13, Dado & Dar 14, KM & Waxman 16)

Issue: tension w. Fermi gamma-ray limits?
relevance of “low-energy excess problem”(KM, Ahlers & Lacki 13, Senno, Meszaros, KM+ 15
KM, Guetta & Ahlers 16, Ando, Tamborra & Zandanel 16, Bechtol+ 16)

confinement time, ∝ E −s [2tion spectrum dN/dE ∝ E −p
This power-law index is close
IceCubec2than, the theoretical value p
ζtH [4ν(dLν /dV )]ν=1.4GHzEν Φν (Eν = 1GeV) ≈4π
IceCubeenergy per logarithmic partic= 10−7 ζ0.5 GeV cm−2 s−1 sr−1 .
(2)
Fermi acceleration in strong
ticle approximation [26]. We
Here, tH is the age of the Universe, and the factor
spectrum observed on Earthζ = 100.5 ζ0.5 incorporates a correction due to redshiftof the cosmic-ray distribution
evolution of thegalaxy
star formation
rate relative to its presentgroup/cluster
The inferred excess relative t
day value. The value of ζ0.5 ∼ 1 applies to activity that
> 1 GeV photon flux from theCR sources: AGN, galaxy mergers, virial shocks
traces the cosmic star formation history [6]. Note thatthe cosmic-rays are generate
Kotera, Allard, KM,
Aoi, oscillations
Dubois, would convert the pion decay flavor raflavor
smaller than the value p = 2
Pierog & Nagatakitio,
09 νe : νµ : ντ = 1 : 2 : 0 to 1KM,
: 1 Inoue: 1 [11],so that 08& Nagataki
cosmic-ray distribution, andΦνe = Φνµ = Φντ = Φν /2.
index of cosmic-rays in the in
the local one [27]. The spectr−510in SNe is inferred to be a pow± 0.1 over a wide ra
cted event rates for muon neutrinos (nm ! n¯ m) in IceCube-likestarburst
galaxy neutrino (ne ! n¯ e ! np∼m !=10n¯ m2.1
Fig. 2.—Cumulative! nt ! n¯ t) background from
TeV,
onradio,
ve nearby CGs: Virgo, Centaurus, Perseus, Coma, and OphCGs for broken power-law CR spectra with p1 p 2.0
andbased
p2 p 2.4. The
breakX−6
17.5AGNpower-law CR spectra with p1 p 2.0, p2 10
p 2.4,CRand sources:
!b p
(e.g.
[28]).
hypernovae, GRBs,eV (thick lines) and!b p1016.5 eV (thin lines), reAMANDA(ν ); Baikal(ν ) energies are !b p 10µ
e2med, and the isobaric model with XCR p 0.029 is used. Note˙ a steeply
spectively. The CR power is normalized to !For(dn/d!)
p 2 #falling
1045 ergproton
Mpc"3−2
KM3NeT mainly cover the northern and southern celestial,CRs
theaboveproductionof knee.
neutryr"1 at ! p 1018 eV, as required to accountEfor
the second
pectively. Neutrino oscillation is taken into account. [See the
For the isobaric model, the correspondingnated
XCR is by
0.029
and 0.067.
For the E
protonsof energy−7n of the Journal for a color version of this10figure.]
central-AGN WBmodel,
is assumed
kCG p
BoundKolmogorov-like turbulencecosmic-ray”knee” withcorrespond30
2 "1
IceCube10 cm s . We take tdyn p Dt p 1 Gyr ogy
and zwith
2. WB
representsinject
theStar Bursts
max p theGalactic
Waxman-Bahcall
bounds(Waxman&
Bahcall1998).
he neutrino spectra using formulae based on the2rays, we expect the neutrino
0.1 km−8
E2ν Φν [GeV/cm2 s sr]ground. The cumulative GeV neutrino background fromstarburst galaxies is then10
e at high energies (Kelner et al. 2006).
2 SB
−0.1
≈ 10−7 (E/1GeV)
where CGs are assumed to be theEmainofνCRsfromν Φν sourceso and gamma-ray fluxes can be estimated via the1 km2 knee
the second
to the ankle. Here,upn CG
is thelocal
densitytical depth for the pp reaction asAtmospheric→fp p ≈← GZK
to (0)∼ 0.1
PeV.
In fact,
theLoeb & Waxman 06
of massive CGs and fz is a correction
factorfor thesourcewhere nN is the target nucleon density
10 in the ICM,
trum forstarburst
galaxies
ma
10
10
10
10
10
evolution(Murase2007;
Waxman&Bahcall1998).
For
decross section, and tint ∼ tdyn or max(r/c, tdiff) is thethan in the Galaxy. The ste
E [GeV]
−9

3

"4.5

"3

5

7

ν

9

11

Inelastic pp Neutrinos from CR Reservoirs
Explain >0.1 PeV ν data with a few PeV break (theoretically predicted)








     •  KM, Ahlers & Lacki 13 PRDR
updated @ Neutrino 2014
diffuse γ-ray bkg,

diffuse ν bkg.







diffusive escape of CRs



 




















Unification of neutrinos and gamma rays

Inelastic pp Neutrinos from CR Reservoirs
Explain >0.1 PeV ν data with a few PeV break (theoretically predicted)
Escaping CRs may contribute to the CR flux (theoretically predicted)
10-5

2

-2 -1

-1

E  [GeV cm s sr ]••KM & Waxman 16
see also Katz et al. 13

-6

10

-7

10

pp
pp 

Fermi
Fermi

IceCube

pp 
pp

Auger

CR
CR

Auger

-8

10

cosmogenic -910

10-10 010

cosmogenic
 
cosmogenic

102

104

106
E [GeV]

108

1010

Grand-unification of neutrinos, gamma rays & UHECRs※cosmogenic ν flux does not violate the latest EHE limit by IceCube

Neutrinos from Dark Reservoirs
Quasi-isotropic emission from the Galactic halo (e.g., DM) can be constrained    



KM, Laha, Ando & Ahlers 15 PRL  ex. Feldstein et al. 13,
Esmaili & Serpico 13,
Higaki+ 14, Fong+ 15,
Bai+ 14, Rott+ 15












     

DM → νe+νe (12%)
DM → b+b (88%)





(similar results in othermodels that are proposed)





•
•































Galactic: γ → direct (w. some attenuation), e± → sync. + inv. Compton
Extragalactic → EM cascades during cosmological propagation

adv fppdyn N ∼ (εshs (2πN ρV )−1Φ )σ30(r/1013 cm)

ν

ε

νN

A

&
'
&
'
! (B/G)!Physical
107 (Γ
(3)
2 j /100)
Review
Letters
ε
Φ
V
ν ε
max
≃ 10 yr−12
−8
3 εp
−2
−1
−1
%1
3 GMns 10 GeV53cm s sr
km
∼
3
×
10
erg
(5)
E
≈
B
coh Kohta Murase1 %6:5 p;17
5$ Rns % %
Q
%
%
1
c
dt
Yukawa Institute for Theoretical εPhysics,
2%46gas% ε2 qdensity
dz10
(4)
−1
•
intraclustercohν (ε−3ν )F
νQ= ∼ 3.2 ×νΦ%% νMpcyr(z)ϵcr,−1 Lj,45
ρGC,−5cr 4π
Kyoto University, Kyoto, 606-8502, Japan
dzerg

produ
PeV protons to be confined in GCs, the coherence
GalaxyGroupsandClusters:
Basicsenerg
h of l * 0:34 kpc B "is needed. Assuming
The c
Kolmogorov turbulence with l $ 10–100 kpc
energ
2 -2 cm-3 (center)-4 cm-3, a fewx10
n~10
!
ðr
=6DÞ
’
we have the CR diffusiontime,tN ∼ (εν Φε )σνN (2πNAdiffρV )vir(Dated: February 15, 2014)&'&' 0:34
max
2
ε
≈
ε
Φ
V
p
2
%1=3 1=3
2=3
ε•CR
accelerators
%2=3
ν
−1
GM
3
L ≈ (Ω/Ωns)GMṀ
/r 53≃ 0.9 ×gives
10 erg s M
10 yr
M−8
,
which
Gyr "p;17 B%6:5 ðlcoh =30≃kpcÞ
3(5)
∼
3
×
10
erg
EB ≈ 10
−2
−1
−1
15
GeV
cm
s
sr
km
ð1=3Þ
AGN
(~a
few),
galaxymergers,
5R
11.30.Cp, 98.70.Sa%2 2 ns%3
51 PeVB%6:5 ðlcoh =30 kpcÞ normal
M15 ðtgalaxies
frominj =2 GyrÞ(~100-1000)
Then,
Q ∼461.0 × 10 −3
erg Mpc
yr
ϵ
L
ρ
bρ
−1
UHECR
acceleration
possible
Q
∼
3.2
×
10
erg
Mpc
yr
ϵ
L
¼ tinj . The confinement
of
CRs
with
&
"
cr
cr,−1
j,45
GC,−5in AGNp$
N ∼ (εν Φε )σνN (2πNA ρV )
100 P
&
'
&
'
"
2 b
ε"
Φε $ 0:04"b $V•accretion
shocks
PeV
can
lead
to
hard
spectra
at
&
ν
−1
!
p
t
=
t
≃ 10 yrinj(εp ) fz(1)
GeVÞ
−8 diﬀ−2 s−1ε≈(3/20)(V/c)eBr
∼ 1.2
10
GeV
cm
sr−1EeV Bkm3 V5/3 Mb46−1V, while CRs withLac*"CRbp/Ωinjection
escapeinto
extracluster≈ (Ω)GM Ṁ
/r
≃
0.9
×
10
erg
s
M15
m
vir
occurs for ~1-10 Gyr over a cluster/groupis tdibe,z) making
neutrino spectra
steeperat −3*yr"−1−246! .ϵcr,−1b !
−3b cr ∼ 3.2 ×
2 B
Q
10
erg
Mpc
Lj,45/2
ρ(lGC,−5AGN energetics
"
t
≈
(r
/6D)
≃
1.6
Gyr
ε
/30
kpc)
ε
≈
51
PeV
B
(l
/30
kpc)
M
(t
Gyr)
−6.5 cohpM%4%3p15 inj(2)
ing cluster
typicalintracluster
densities n! $ 10 cm
energetics
Qcr ∼ 1.0 × 1047 erg Mpc−3 yr−1 ϵcr,−1 Lac,45.5 ρGC,−56], with a possible enhancement factor−2 g $ 1 % 35/3 15 Pe
fpp≈ ≈
σpp
nctintṀ≃%2× 10 gn̄46 (t s−1
/2 M
Gyr)
pp efficiencyLac(Ωκbp/Ω/r0.76m )GMvir ≃ 0.9 × 10 −4ergint
If
15
7
1],
’ 0:76[1] '10 Phys.
gn!Rev.
ðt=2
GyrÞ.
K. Murase,
Lett.
103,
081102(2009).
10 (Γj we/100) get(3) fppmax%4 int1/3
ε≈(3/20)(V/c)eBr
∼
1.2
EeV
B
V
M
s
sh
−6.5
s,8.5
p
15
SBGs
, we achieve E2 " $10%9 –10%8 GeVcm%2 s%1 sr%1 ,
ac

b

max
p

!

!i

47

46

vir

47

cr

diﬀ

m

−3

s

−1

−1/3
p,17

−1

1/3
−6.5

5/3
15

ac,45.5 GC,−5−6.5 s,8.5

sh

2
vir

−3

cr,−1

−1

1/3
15

−2/3

coh

2/
15

s,
n

Diffusion Break & Second Knee
(Dated: February 15, 2014)

Qcr ∼ 1.0 × 1047 erg Mpc−3 yr−1 ϵcr,−1 Lac,45.5 ρGC,−5, 11.30.Cp, 98.70.Sa

Physical Review Letters- Maximum energyof CRs is expected to be high enough
1/3
max
εp 1≈ (3/20)(Vs /c)eBrsh ∼ 1.2 EeV B−6.5 Vs,8.5 M15(whichKohta
is notthe case in normal/starburst galaxies)
Murase1 "Yukawa Institute for Theoretical Physics,
21 eV)→
confining
CRs
is
easy
(E<eBR~10
t
=
t
diﬀ
inj
qp (εpKyoto)- fzBig!
(1)
University, Kyoto, 606-8502, Japan
1/3

−1/3

−2/3

2
CR diffusion time tdiﬀ ≈ (rvir(Dated: July 23, 2016) /6D) ≃ 1.6 Gyr εp,17 B−6.5 (lcoh /30 kpc)p (z)εbp ≈ 51 PeV B−6.5 (lcoh /30 kpc)

tdiﬀ98.70.Sa= tinj (2)z, 11.30.Cp,
diff. flux dJ/dE · E2.5 / (m-2 sr -1 s-1 eV1.5)

1017

710

−2

63

W.D. Apel et al. / Astroparticle Physics 47 (2013) 54–66

2
M15(tinj /2 Gyr)

2/3

M15

−3

EAS-TOP (Astrop.Phys.10(1999)1)
Tibet-III, QGSJET 01 (ApJ678(2008)1165)
GAMMA (ICRC 2011)
IceTop (arXiv:1202.3039v1)
TUNKA-133 (ICRC 2011)
Yakutsk (NewJ.Phys11(2008)065008)
KASCADE-Grande, QGSJET II (Astrop.Phys.36(2012)183)−2 081102 (2009).
[1] K.
Lett.
f Murase,≈ κ σ Phys.
nct Rev.
≃ 0.76× 10103,gn̄ (t /2 Gyr)pp

Akeno (J.Phys.G18(1992)423)
AGASA (ICRC 2003)
HiResI (PRL100(2008)101101)
HiResII (PRL100(2008)101101)
AUGER (arXiv:1107:4809)
AUGER AMIGA infill (ICRC 2011)p pp! 10 (Γj /100)
(3) 2
−2
−3
"
(l
/30
kpc)
M
(t
/2
Gyr)
−6.5 cohinj(εν ) fz
(1) 15
16

1015

−2

2
ct
≃)F
/2 Gyr)(z) × 10 (4)gn̄−4 (tint
$0.76
ν (εν
ν qintb
KASCADE-Grande, all-part., QGSJET II (this work)
KASCADE-Grande, light (p), QGSJET II (this work)
KASCADE-Grande, medium (He+C+Si), QGSJET II (this work)
KASCADE-Grande, heavy (Fe), QGSJET II (this work)

15

10

16

−4

erg Mpcyr

εp ≈ 51 PeV B−6.5 (lcoh /30 kpc)

(2)
primary energy E/eV
1017

10

int

- CR break compatible w. 2nd knee
tdiﬀ = tinj
- Escaping
CRs naturally contribute tond knee−3
45 the observed−1CR flux above 2

Qcr ∼ 8.5 × 10

KASCADE, all-part., QGSJET II (see Appendix A)
KASCADE, light (p), QGSJET II (see Appendix A)
KASCADE, medium (He+C+Si), QGSJET II (see Appendix A)
KASCADE, heavy (Fe), QGSJET II (see Appendix A)

2
CR qCR 10 fz

int

18

ϵcr,−1 ϱSFR,−2

−2

2
M15
(tinj /2 Gyr)−3

1/3
1/3 −1/3
ej /c)eBRSed ≃ 3.1 PeV B−3.5 Eej,51 Vej,9 n
−2
−3
b
b
2
−3
−1
(5)
ε
≈
0.04ε
≃
2.0
PeV
B
(l
/30
kpc)
M
(t
/2
Gyr)
ν break
−6.5
coh
inj
energy wheredependent
ν the charge
pknee of iron is expected, if the
15cr,−1SFR,−2

Apel et al. 13
APh≈ (3/20)(Vεmax

he all-particle spectrum obtained in this work based on an unfolding of KASCADE-Grande measurements, and the spectrum obtained in [32] based on an unfolding
DE measurements (see Appendix A), are compared to spectra determined by other analysis methods of our collaboration [10] or other experiments (see legend fors). Additionally shown are some elemental spectra representing different mass groups (see legend). The error bars denote statistical uncertainties, error bands thec ones (the latter ones are only shown for the results of this work, as well as for the results obtained by the alternative analysis methods of our collaboration [10]).

53
45
10
erg
10
p (z) erg Mpc

mary and conclusion

p

yr

(3)

two-dimensional shower size spectrum of charged particles
ons measured with KASCADE-Grande was unfolded. Basedϵϱknee at about 3 PeV to 5 PeV is assumed to be caused by a decreasein the flux of light primaries (protons and/or helium).
However, there is still uncertainty about whether the applied

KM, Inoue & Nagataki 08 ApJL

Galaxy Clusters/Groups, CRs, νs
Pre-IceCube predictions motivated by the explanation of observed CRs

ROM CLUSTERS OF GALAXIES

L107

Normalized by CRs above 2nd knee (s=2.0)(only massive clusters included)pp	
KM, Inoue & Nagataki 08 ApJL

Normalized by UHECRs (s=2.3)
clustersOFincluded)
No. 1, 2009 (low-mass
PROPAGATIONULTRAHIGH ENpp	pγ	
Kotera, Allard, KM+ 09 ApJ

Figure 11. Diffuse neutrino fluxes obtained with galaxy cluster density ns =10−5 Mpc−3 and AGN cosmic-ray luminosity Lcr = 1045 erg s−1 . A mixed
composition is injected at the center of the non cool core cluster with Bc = 1 µG
Fig. 2.—Cumulative neutrino (ne ! n¯ e ! nm ! n¯ m ! nt ! n¯ t) background from(red thick solid), and in cool core clusters with Bc = 30 µG (black thick solid)
CGs for broken power-law CR spectra with p1 p 2.0 and p2 p 2.4. The break
Bc = 10 µG (black thin solid), Bc = 3 µG (black dotted), and without magnetic
energies are !b p 1017.5 eV (thick lines) and !b p 1016.5 eV (thin lines), fieldre- (green dash dotted). We also present the cases of a pure proton injection
at"3
the center (blue long dashed) and a mixed composition injected at 100 kpc
245
˙
spectively. The CR power is normalized to ! (dn/d!)
p 2 # 10 erg Mpcfrom the center of a cool core cluster of Bc = 10 µG (pink solid).
yr"1 at ! p 1018 eV, as required to account for CRs above the second knee.
(A color version of this figure is available in the online journal.)• Consistent w. obs. & a multi-PeV break was predicted• No firm gamma-ray detection, low-mass clusters neededCR injection luminosity can be Lcr ∼ 1045 erg s−1 if ∼ 10% goes to CRs. In additi
e AGN such as Fanaroﬀ-Riley (FR) II galaxies, may have such high CR luminosit
their luminosity could have been higher in the past. Supernova remnants may hav
parable energy budget, although CRs may suﬀer from adiabatic losses. In any case,Cosmic-ray
one cluster
CR energy
stored inconfined
the GC is inestimated
to be

Neutrino Limits

Ecr ∼ Lcr × min[tinj , tdiﬀ ]!
""!
min[tinj , tdiﬀ ]Lcr≃ 1061.5 erg
,
45
−1
Gyr
10 erg s(2.

e tinj is the CR61
injection
timescale, which is typically order of ∼ 1 − 10 Gyr, and
62
~10
-10
erg needed to explain CRs or νs−1 !
dS
dS timescale.
CR
diﬀusion
ee R≡ R(E)= (E 2 dE)dE (E dE
) is the ratio of the bolometric flux to theential flux at E (see figures 1 and 2).
13 JCAPAs in eq. (2.3), the intensity (per unit energy, area, time KM
and& Beacom
solid angle)
is given b
For CRs, eq. (2.12) leads to (for gamma rays or neutrinos)# lmax
#
70
Lcr
1
Ecr
1
2
Virgo
1
dScr dσpp ξ
fpp≈n̄ κ σ c
E FE ≈′
2 N π pp R
69
8πd2 I R(Θ)
8πdFornax
cr
cr
= "
dE p
c
(2.
E
%2 cr (r) Perseus%$ dl%$nN (r)n
′
′
#2$ E
n̄
16
Mpc
20
dE
dE
68
cr
N
+ z)
p
−lmax
Coma
≃ 1.5×10−10 GeV cm−2 4π(1s−1(2.16)
−4
61
−3
10

cm

10

erg

Rcr

d

67

Ophiuchuslog(Ecr [erg])e ξ is the eﬀective multiplicity of gamma rays or electrons/positrons or neutrinos, c isive velocity between an incident proton and a target nucleon, and the CR normalizat

IceCube started to constrain
the relevant parameter space!

JCAP02(2

−1 !
66
cr
cr
dEp (Ep dS
e Rcr ≡ Rcr (Ep ) = (Ep2 dSdEp )dEp ) and we assume that the gamma ray or
ino roughly carries a half the energy of the mesons. Since CRs are not depleted by 65
theaction, the pp meson production eﬃciency is estimated to be fpp (Ep ) ≈ n̄N κπ σpp ct64
int ,
−26
2
e κπ σpp ≈ 10
is the eﬀective cross section of meson production, and tint is theee Model B cm
in ref.
[29]. Ref. [29] also considered the one-zone
model by estimatingIceCube
the ICM5yr
densit63
action time of CRs. If CRs are trapped in GCs, we expect tint ≈ tinj , and the injection
hockradiusA), butof theexternal shock
may
62becale maybe the (Model
dynamical timescaleaccretion/merger
shocks, orradius
the clusterage
if rather large, ∼ 2rvir [38, 43].
are continuously supplied by AGN inside the GC. If the CR escape becomes relevant,61
pect tint≈ max[t, r200 /c],taking into
account
that the transport
velocity is limited(seen
indiﬀtheIceCubepoint
sourcepaper 2014)60in[vdiﬀ , c]. In the latter case, when the diﬀusion coeﬃcient increases with energy,
1.5
1.75
2
2.25
2.5
2.75
3
ma-ray and neutrino spectra become steeper than injection CR spectra.
sGamma-Ray Limits?
Coma

KM+, in prep.

models have to be consistent
with non-detection by Fermi(but connection to the diffuse
flux is actually not trivial)

KM, Asano & Inoue 08 IJMPD

65

Virgo

64

log(Ecr [erg])

IceCube 5yr
63
62

Fermi

61

KM & Beacom 13 JCAP

60

1.5

1.75

2
s

2.25

2.5

galaxies M31 [75], Large Magellanic Cloud (LMC) [and Small Magellanic Cloud [77] are considered.
signal is stronger for objects with larger M dm =d2, wh
Mdm is the dark matter halo mass and d is the dista
Virgo, Fornax, M31, and LMC are of particular inte
and they have Mdm =d2 ∼ a few × 1013 M⊙ Mpc−2 .
IceCube observatory has its highest sensitivity for p
source emission
27 sin the Northern Hemisphere utilizing
τdm ~ a fewx10
going muon neutrino events. For this reason we focus
on Virgoscenario
and M31. Note, howe
needed following
in the discussion
DM decay
3
that a proposed km scale neutrino telescope like KM3[78] in the Mediterranean Sea should be helpful
neutrino
observations
from Fornax
and LMC in
nearby DM
halos(galaxies,
clusters)
Southern Hemisphere. Although we numerically evalenable us
tofluxes,
testforDM
modelssignalexample,the muon neutrino flux
estimated to be

Application to Dark Matter• Clusters are also storage rooms of dark matter (DM)

Warren, Abazajian, Holz &Teodoro 06 ApJ

90o

E2ν ϕνμ ≈

Coma
Virgo

37
9

DM

23

DM
25
%

50
Galactic Plane

180o

Andromeda

1

Nort
hern
Hem
Sout
isph
hern
ere
Hem
isph
ere

34

11

Ophiuchus

24
25

6

4

35

14
33

26

8

36

29

13

Perseus

16

17

%

31

3

27

5

2

22

15
12

30

LMC
19

SMC

Fornax

18
21

20

7
10

-90o

KM, Laha, Ando & Ahlers 15 PRL

Galactic-180o

1 Mdm c2
12πd2 τdm Rν

−1≃ 1.3 × 10−10 GeV cm−2 s−1 τ−1dm;27.5 ðRν =15Þ
"!
"−2
!
Mdm
d
×
;
16 Mpc5 × 1014 M ⊙for the Virgo cluster. Then, following Refs. [55,we calculate detection rates of through-going muon tra2
within a maximal angulardm
range Δθmax ≃ max½Δ
0.5°ðEν =TeVÞ−1=2 $, where the angular resolution is seΔθres ¼ 0.5° for IceCube [73] and the second term is duflux ∝ M/Dcompatible with "-ray data, but no identification yet.

What’s Next?: Need to Identify the Sources

n 20% to the diffuse !-flux.

e star-forming galaxies) problematic.

IceCube-Gen2

ected yet.

CTA

IceCube-Gen2

Markus Ackermann | 04.05.2015 | Page 31

70

Heavy DM scenario(nearby DM halos)

68 67  



IceCube-Gen2
can exclude models!

log(Ecr [erg])






Virgo
Fornax
PerseusComa
Ophiuchus69

ruled outby diffuse γ bkg.

66
65
64
63
62

KM, Laha, Ando & Ahlers 15 PRL




  

      
      !

IceCube-Gen2
can exclude models!

61
60

1.5

1.75

2

2.25
2.5
2.75
3
s KM & Beacom 13 JCAP

L

0

L

G⌫⌫

G¯
⌫Z
6 ⌫

G¯
6 0 ⌫0 ⌫L L G¯
⌫⌫Z
6Z

L G⌫⌫
(16)
Multiplet
Searchesare
Independently
Powerful
L G¯
⌫Z
6 ⌫
point
sourcepoint source

point source0

point source(1✓✓ ⌦◆◆✓ e↵⌦ 3◆ ✓ ◆ (17)e↵1on3 ⌦ the number density
Non-detection of point sources“upper”⌦ ne↵
Ns give= bNm,L
d3limn<
(1
=
b
d
1 3
0 limits
s
m,L
0
=lim
bm,L
Ns = bm,L< 1 lim <ne↵
3 nN0s3d
0 dlim < 1
3 KM, Beacom & Takami 12
For early (quasi-ignored) papers, Lipari 08, Silvestri& Barwick 10,
3!1/2!1/2 ✓✓◆◆ 1/2
e↵!E1/2Le↵
!
◆ 1/2
E
L
e↵
e↵ F 1/2 ✓
⌫
⌫
!
!
E
E
⌦
⌫1/2
⌫µ
E
L
E
L
1/2
lim
!
!
µ
⌫
⌫
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◆
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1/2
E ⌫µ
E✓
e↵
3
F
e↵
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' 72
(1
dlim E⇡
1/2
E⌫42LE'⌫µ72
Ns = bm,Ln⌫0LdE4⇡F<(18)
E⌫1LE⌫dµlim
E1⌫MpcLE⌫µ 1042 9 GeV
⇡ Mpc
lim
19
⌫µ limFs limlim 2 10
1Fcm
2s 1
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s
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s
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cm
lim
' 72 Mpc
dlim ⇡ dlim ⇡' 72 Mpc
1
2s 1 2
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1042 erg 10s 42
erg s 1 10 9 GeV
10 9cmGeV
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◆
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L
1/2
⌫
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b
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⌫µ lim
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lim
m,L
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e↵ E⌫ LE⌫73F10lim !
n . 2.5 42
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✓ 52 s 1 ◆ 12⇡✓ 5 ◆ 1 2⇡(2
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' 72 Mpc n0 .422.5 ⇥µ101 Mpc 0 E910
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5
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b
⇠
F
⌦
m,L
z
lim
E
⇡
⇠
3
⇥
10
(2
e↵
5
3
B
n
&
0.8
⇥
10
Mpc
“lower”
limits5R0ns
9neutronstar✓◆2 ✓ ◆ 3 ✓◆ 3 5✓◆0.6
2
2⇡
10 GeV cm 2 s 1
b
⇠
F
⌦
m,L
z
lim
3
2
Mpc
(22)
3 GMns⇠negative)
3 ⇥ 1053 erg
532⇡
10 9 GeVcmEB2weaks⇡ 1 (evenclusteraccretion
shock
model:
evolution,n0eff~10-6 Mpc-3
5R[1] K. Murase,
Phys. Rev. Lett.
103,ns081102(2009). evolution, n eff~10-5 Mpc-3
cluster/group internal
accelerator
model:
positive
0

L

0

G¯
⌫Z
6 ⌫

[1] K. Murase, Phys.
2 Rev. Lett. 103, 081102 (2009).

3 GMnsafter IceCube’s
ForEB
discussion⇡⇠ 3 ⇥ 1053 erg discovery, Ahlers & Halzen 14, Kowarski(23)15, KM & Waxman 16
5 Rns

εp ≈ 51 PeV B−6.5 (lcoh /30 kpc)
ctH 3
Eν2 Φν ≈fmes ε2CR qCR fz(2)
4π 8(Dated: February 15, 2014)
ACS numbers: 98.70.Rz, 11.30.Cp, 98.70.Sa

M15 (tinj /2 Gyr)

Starburst/Star-Forming Galaxies% dz dt| dz |qp (z)98.70.Sa
S numbers: 98.70.Rz,
11.30.Cp,
fz = 1+ztH qp

εbν ≈ 0.04εbp ≃ 2.0 PeV B−6.5 (lcoh /30 kpc)

(3)

−2

−3

2
M15
(tinj /2 Gyr)

− 1 Mpc−-3
3 yr-1])log(E dQε 2 Q[erg]CR/dEyr[ergMpc"
ctH ! 2fpp ≈ κp σpp nctintdensity≃ 0.76× 10
gn̄−4 (tint /2 Gyr)tdiﬀ=−2tinjEν2 Φν ≈ 13 ε−1
q
(ε
)
fz 7
(1) • High-surfaceν ν ν30(r/10 4πcm) ! (B/G) ! 10 (Γj /100)(4)!
"
M82, NGC253: Σg~0.1 gcm-3 → n~200 cm-3
ctH fmes 2
tdiﬀ−3=yrt−1
inj
εp qp (εp ) f$z(1)Φν ≈Qcr ∼MSG:
8.5 × 1045
erg
Mpc
ϵ−2
ϱ2SFR,−2
-3
-3−3
cr,−1
#
b
high-z
Σ
~0.1
g
cm
→
n~10
cm
4π
43
g
ε
≈
51
PeV
B
(l
/30
kpc)
M
(t
/2
Gyr)
ct
3
−6.5
coh
inj
2
2
ν
CR
p
15
2
EνH
Φν ≈ fmes
fmes
ECR
CR (ξ
ε2CR
qΦ
fzz/ξz )(2)(5)CRν Φν ≈-3
8submm gal. Σg~1 gcm → n~200 cm-3
4π 8# dz dt
Qcr ∼ 8.5 × 1044 erg Mpc−3 yr−1 ϵ−2cr,−1 ϱSFR,−3
−3
|
|q
(z)
b
2
'
'
p
•
Supernovae,
hypernovae,
GRBs,
AGN
etc.
1+z dz&
ε
≈
51
PeV
B
(l
/30
kpc)
M
(t
/2
Gyr)
−2
−6.5
coh
inj
'
'
b
b
2
15
fz = 2 % dzc dt ' dt ' 2(2)εν p≈ 0.04εp ≃ 2.0 PeV B−6.5 (lcoh /30 kpc)
M15 (tinj /2 Gyrεν Φν =tH q
dz
ε
q
(ε
)F
(z)
(6)
ν
ν
ν
|
|q
(z)
'
'
p
SNR
shock
p
4π dz
dz
fz = 1+z
(3)
1/3
1/3
εmax
≈ (3/20)(Vej /c)eBRSed ≃ 3.1 PeV B−3.5 Eej,51 Vej,9 n−1/3
tH qp
p
−2
eﬀectivetime
drops
quicklywithenergydue
to pion
f
≈
κ
σ
nct
≃
0.76
×
10
gn̄−4
(tint /2
Gyr)
pp
p
pp
int
46
2
2Zatsepin
3 1966).
10−1b2
3 GMns3
748
production(Greisen
1966;&
Kuz’min
−2
53
(lint
/30
kpc)
/2
cm) !
!∼
103 ×
(Γ10
(3) (7)"p ⇡ 51
coh≃
inj(t
fppPeV≈ κpB
σpp6.5nct
0.76
× 10 M15gn̄(t−4/2Gyr) cutoﬀ
EB (B/G)≈erg
j /100)intGyr)This
predicted
Greisen-Zatsepin-Kuzmin
(GZK)
5
R
−1
ns
13
7
SFG
CR energy
MilkyCR budgetis clearlyobserved
intdiﬀ
the ~flux(e.g.Way
Bahcall& Waxmantbudget0 47cm) ! (B/G) ! 10 (Γj /100)
(4)
pp =

2003; Abbasi et al. 2008; Abraham et al. 2008) and theinferred generation
rate is−3
roughly45−1 constant to at least% (2πN% A ρV )CR
20
$
45
Q
∼
8.5
×
10
erg
Mpc
yr
ϱSFR,−2
N ∼46
(ε
Φ
)σ
2 ϵcr,−1310eV(e.g.
Bahcall&
Waxman2003;
et al. 2009),
ν
ε
νN
cr
−3
b
b
2 Katz45−1%(dt % 2 (AMS-02)
c10
Qbeyond
∼ PeV
8.5
×B
10 6.5erg
yr measured.
ϵcr,−1
2.0(lflux/30
kpc)(tϱinj/2Gyr)) ( "⌫ ⇡) 0.04"p '3M
cr
SFR,−2coh−3Mpc
b which
3 poorly
15
the
is
2
%
%
εp ≈ 21 PeV D0,26 Σg,−1 (h/kpc)
dz(4)= 45 3 −1εννΦ)FVε (z)% εν qν (εTherate estimate, Eq. (1), is based on the direct mea10 yr % dz2 −8
2 ≃4π
ν
CR
star-forming
3−2 (s=2.2)
(5)
CR (ξ
cm
km
ν Φν ≈ fmes E10
CR ΦGeVz /ξ
z s−1) sr−1
SBG
CR
energybudgetsurementof UHECRs
and the well understood physics
44 8 MW , S t a r b u r s t s ∝ S F R
of proton-CMB interaction and is accurate (to ∼ 30%)
composition
is dominatedby 1/3
protons.
1/3 If44−3−1
max as long as the44
23.1
tadv
=
tdiﬀ
UHECR
10
Q
∼
8.5
×
10
erg
Mpc
yr
ϵ
ϱ
ε
≈
(3/20)(V/c)eBR
≃
PeV
B
E
V
nto−
cr
cr,−1
SFR,−3
f
⇡

nct
'
0.76
⇥
10
gn̄
(t
/2
Gyr)
ej
Sed
−3.5
−3
46
−1
the
compositionisdominatedbyheavier
nuclei
(up
p
43
2
pp
p
pp
int
4
int
ej,51
ej,9
(Auger)IceCube

bound
Qcr ∼
×
10 'erg Mpc' 53 yr ϵcr,−1 Lj,45 ρGC,−5
GM
3 3.2
&ns
iron), the energy generation rate at εp ∼ 1019.5 eV may
'
' 10
∼
3
×
erg
(5)
≈ c KMdt& 'Fukugita
in
prep.
U
H
EC
R
s
I
c
e
c
u
b
e
n
e
u
t
r
i
n
o
s
2
' εν qν (εν )F (z)change by a factor of ∼ few (given the similarity of the
5 RnsΦν =42dzalso(6)
UHECR
energybudgetintegrated
over
'
'
see
Katz
et
al.
13
attenuation
lengthsof nuclei
and protons,
seeUHEe.g. figure
4π
dz
3
−3
b
3
ε
≈
15
PeV
D
V
(h/kpc)p0,26 w,7.5
2inAllard2012).
1/3
1/3 −1
5/3
max
46
−1
41 43
CR (Fermi)(Ωb /Ωm )GM Ṁ /rvir ≃ 0.9 × 10
ac ≈ 10
8

erg s

M

ε

15
p
910 10 11 12 13 14 1515 16 17 18
19 20
20
10
10
10
log(E
[eV])
ε[e
V]
νN (2πNA ρV2 )44
1E(3/20)(V/c)eBR≃ 3.1
PeV3 Byr−3.5
Sedergej,51 Vej,9 nQ≈uhecr⇠ a ejfew⇥ 10
Mpc
tpp = tadv

2.2.

Intermediate energies, 1015 eV ! εp ! 1018 eV

−2#
fpp which≈ κp σpp nct
≃
0.76
×
10
c,
below
D
¼
D
ð"
="
Þ−3gn̄(for
# /2
$Gyr)
0–1).3ð1=3Þlint−43(tint
−2
coh
c
p
c
b 0.76 × 10
ρac,45.5
GC,−5
f
≈
κ
σ
nct
≃
gn̄
(t
/2
Gyr)
p pp
int εp ≈ 15 PeV D0,26−4(h/kpc)(4) ppj /100)%1Vint
2
w,7.5
&
7:2
Myr
B
ðh=kpcÞ
at
Then,
we
have
limitsoftCR
Confinement
andEscape
diff
%3:5
(4)
25 cm2 s%1 for D ¼ D ð" = −1
100
PeV
and
D
*
2:3
'
10
0
0 p
t
≈
t
≈ h/V−3
3.1 Myr (h/kpc)V
esc
adv
w ≃−1
,45.5 ρGC,−545w,7.5
Qcr ∼ 8.5 × 10 erg Mpc yr ϵcr,−1 ϱSFR,−2
1=3
−3
45
−1
- Low-energyCRs
areadvectedbystarburst-driven
in Q
the
Kolmogorov
turbulence.
The
diffusion
time winds
R GeVÞ
1/3
∼
8.5
×
10
erg
Mpc
yr
ϵ
ϱ
cr
cr,−1
SFR,−2)(5).5 Vs,8.5 M15%1=3−1
2 , (h/kpc)V
time ’tesc
tadvD≈%1
h/V
≃
3.1
Myr
is(5)tdiffadvection! ðh2 =4DÞ
1:6≈Myr"
ðh=kpcÞ
givingw
w,7.5
0;26 p;17
3b ! 213 (for−3t −1
b !
44
1/3 PeV D%3#
ðh=kpcÞ
<
t
)
or
"
"
Q
∼
8.5
×
10
erg
Mpc
yr
ϵ
ϱ
pp
adv
p
p
−1
cr
cr,−1
SFR,−3g;%10;26
5 Vs,8.5 M15
f
≈
κ
σ
nct
≃
1.1
Σ
V
pp efficiency
−3
44
−1
pp
p
pp
esc
g,−1
w,7.5 (tesc /tadv )
%3
3
3
Q
∼
8.5
×
10
erg
Mpc
yr
ϵ
ϱ
cr
Vw;7:5 ðh=kpcÞ (for tadv < tpp ).cr,−1 SFR,−3
D0;262/3(z)15 PeV
(6)
−2/3
/30
kpc)
M15
fpp(6)>~1↔︎ “calorimetric”:
almostholds
all CR
energyis usedfor ν & γ
If proton
calorimetry
largely
[55],
MSGs
and
−1
1/3 (tesc
1/3/t−1/3
fpp ≈ejκσpp nct
1.1
Σg,−1Vw,7.5
max
p%9
esc
adv )
ε
≈
/c)eBR
≃
3.1
PeV
B
E
V
n
2(3/20)(V
%7
%2
%1
%1
Sed
−3.5
p
ej,51
ej,9
SBGs−2/3
may
have E! "!i $ 10 –10 GeV cm 1/3
s sr1/3 ,−1/3
max 2/3
30 kpc) εp M15≈ (3/20)(V /c)eBRSed ≃ 3.1 PeV B−3.5 Eej,51
Vej,9n(Loeb from
& Waxman 06 JCAP)
sufficient
A break could come(7) for the INB ejflux [13].
tdiff ¼ tpp or tdiff ¼ tadv . But we may simply expect a PeV
tppmax= tdiﬀ(7)2009).
cutmax- Diffusive
high-energy$ 0:04"isp morefor "important$ 100forPeV(e.g., by CRs
cutoffdue to "! escapeptpp = tdiﬀ
(a)
f
>1
→
a
break
is
determined
by tCRs
hypernovae),
where
the
locallyobserved
diff=tppabove
)(
) pp
V (b)
009).
3
−3
bdifferent
3
f
<1
→
a
break
is
determined
by
t
=tadv
$100
PeV
would
have
origins.
ε
≈
21
PeV
D
Σ
(h/kpc)pp
diffp0,26 g,−1
3

−1

) km

V
3
m
L ρ

b

−3

3

3

(KM, Ahlers & Lacki 13 PRDR)εp ≈ 21 PeV
D0,26DISCUSSION
Σg,−1 (h/kpc)
In caseIV. (a)SUMMARY
AND
3

−3
b
b
3
ε
≈
0.04ε
≃
0.80
PeV
D
Σ
(h/kpc)νp0,26 g,−1
A crucial step towards revealing the originof theIceCubej,45 GC,−5signalis the discrimination
pp theandGalactic
p$ scenarios.
※ diffusion
coefficient D0 mustbetween
smaller thanone (D0~1028 cm2 s-1)
tbe
adv = tdiﬀ

Luminosity Function & Calorimetry
LF is described by the Schechter function

Grupionni+ 13 MNRAS

α~1, L*~1011 Lsun: typical infrared luminosity

Redshift evolution: m~3-4 up to z~1 for (1+z)m

SFR ∝ LIR (Kennicutt law)Lγ ∝LIR1.17 (Fermi collaboration 12 ApJ)
(basic agreement w. calorimetry)→ “typical” muon neutrino luminosity:
ELE ~ 2x1040 erg s-1“effective” density: n0~10-5 Mpc-3
can be reached by Gen2 (KM & Waxman 16)  # !  %&'()%*'+,
) *01)2*+,-.*34 *5 !*56
/

#

!"

Star-Forming/Starburst Galaxies, νs, γs








!"

9#:$

78

'





(


# 

!"

!"

!

"

!"

!

!"

#

!"

$

!"

)*+,-./

%

!"

&

!"

'

Tamborra, KM & Ando
14 JCAP!"• gamma-ray
Consistentw. obs.and& neutrino
a multi-PeV
break
isblack)
possibleDi↵use(in magenta)
intensity (indashed
E 2 I(E) as a
the energy for our canonical model, assuming SB = 2.05, 2.15 and 2.3 (from top to
• How
can
CRs inget
PeV?
he Fermi
data [5]are marked
red,accelerated
while the IceCubeabove
region is100
plottedin light blue [35].

Necessity of Super-Pevatrons!"

Our Galaxy’s CR spectrum
Knee at 3 PeV→ neutrino knee at ~ 100 TeV'(/)0 1( 2)*+,-)34 /)5 !)56 !.

Tamborra, Ando & KM 14 JCAP

So ordinary supernovae (SNe) are notsufficient to explain >0.1 PeV data!"

03,789,&:;<=>8<)38<>??
:;<=)38<>??
!"Possible solutions
1. Hypernovae (HNe) KM+ 13, Liu+ 14, Senno+ 15
2. Gamma-ray bursts Dado & Dar 14, Wang+ 15
3. Low-luminosity gamma-ray bursts/
Trans-relativistic supernovae
4. Type IIn supernovae Zirakashvilli & Ptuskin 16
5. AGN jets/disk outflows KM+ 14, Tamborra+ 14
6. B fields amplified to ~mG KM+ 13

%
#

!"

$

( )*+,-.

!"

Figure 4. Di↵use neutrino intensity E⌫2 I⌫ (E⌫ ) as a function of the energy. The magenta line is theflux obtained adopting the luminosity function approach, the pink band defines the uncertainty band
coming from Eq. (2.4). The IceCube estimated flux as from [35] is marked by the light blue band. Our
computed flux falls within the astrophysical uncertainties on the IceCube region at ⇠ 0.5 PeV energies.
For comparison the di↵use neutrino intensity including an exponential cuto↵, exp( E⌫ /80 TeV), isplotted in violet.

Senno, Meszaros, KM, Baerwald& Rees 15 ApJ

intensity is always slightly lower than the Fermi data, SB = 2.05 is currently excluded by
the IceCube data (top panel). In order to allow such hard spectra, lower ratios of L to
LIR are needed. On the other hand, interestingly, an injection spectral index SB = 2.15
can almost explain the Fermi and IceCube data at the same time (middle panel), althoughsome contributions from other gamma-ray source populations are needed to fit the di↵use
EGRB spectrum. The panel on the bottom shows the di↵use intensities of gamma rays andneutrinos for SB = 2.3: The resultant gamma-ray intensity is lower than the one measured
by Fermi and the corresponding neutrino flux falls below the IceCube band. In order togive an idea of the role of the EBL attenuation for various spectral indices, in Fig. 5 we plot
the di↵use gamma-ray intensity without EBL attenuation (dashed magenta line). Note as it
closely follows the di↵use neutrino intensity and the EBL attenuation is stronger for harder
spectral indices.
In our canonical model we have assumed the spectrum with SF AGN(non SB) = NG
and SF AGN(SB) = SB , as described in Sec. 2.2. However, besides SB , also SF AGN ispretty uncertain and might not follow the distribution adopted in out canonical model. For
example, Seyfert systems (belonging to the SF-AGN class) are classified as SF-AGN (nonSB) according to Herschel [27], while Fermi classifies the observed Seyferts systems NGC

HNe

SNe

How about Radio Galaxies?
Detected by Fermi & possible origin of the diffuse γ-ray bkg.
Q. Can they explain the IceCube flux like starbursts?

Hooper, Linden & Lopez 16
1/3
2
1"p,17 (R/3 kpc) non-calorimetric!
fpp in elliptical galaxies: fpp ' 1.2 ⇥ 10 3 n 1 D0,27.5

accelerators
Manyof radio galaxies show time variablity → more compact
Efficient pp inside jets leads toe↵the energetics
crisis (Atoyan & Dermer 01)
1/2
2
fp ⇡ n̂BL p rBLR ' 5.4 ⇥ 10 LAD,46.5
But AGN core emission is possible (Kimura, KM & Toma 15, Tjus et al. 14)

What’s Next?: Need to Identify the Sources
Starbursts and radio galaxies are already detected by Fermi
For pp scenarios, we have strong predictions for IceCube-Gen2
nearby starburst galaxies
in the northern hemisphere

Number of Tracks (>Eµ )muon neutrinos from nearby Fermi-detected SBGs (for Gen-2)

NGC1068+NGC2146+Arp220+M82
NGC1068+NGC2146+Arp220
s=2.0

1

10

102
Number of Tracks (>Eµ )2

10nearby radio galaxies
in the northern hemisphere

s=2.0
s=2.18010s=2.1810-1
10-2 3
10

10

M87+NGC6251+IC310+NGC1218+4C39.12

101
0

10

s=2.0

s=2.1810-1
atm. bkg.

atm. bkg.
4

muon neutrinos from nearby Fermi-detected RL AGN (forGen-2)

510Eµ [GeV]

10

6

10

7

10-2 310

V=10 km3 & best ang. res.=0.1 deg & 5 yr obs. assumed

104

105
Eµ [GeV]

106

107

KM & Waxman 16

Wrap up: Predictions of CR Reservoir Models••

Explain >0.1 PeV ν data with a few PeV break (theoretically predicted)
Must largely contribute to diffuse γ-ray bkg. (perhaps “common” origins?)







       KM, Ahlers & Lacki 13 PRDR
updated by KM 1410.3680

diffuse γ-ray bkg,

diffuse ν bkg.







diffusive escape of CRs



 




















- Strong predictions: spectral index s<2.1-2.2, >30-40% to diffuse γ-ray bkg.
Proposed tests: 1. (Stacking) searches for neutrinos & γ rays from nearby reservoirs
2. Decomposing the diffuse γ-ray bkg.
3. Measurements of neutrino data below 100 TeV

tion backgrounds including the extragalactic backgrou
light (EBL) and cosmic microwave background (CMB
they propagate over cosmic distances. As a result, hi
energy γ rays are regenerated at sub-TeV energies. S
ondly, intrasource cascades via two-photon annihilat
inverse-Compton scattering, and synchrotron radiat
processes, can prevent direct γ-ray escape. To see thimportance, we temporarily assume that the sources-7-2 see-1in the-1following that
γ-ray transparent.
We will
hypothesis leads to significant tensions with the IGR
10-5
In pp scenarios,
neutrino
and generated
pp ()
KM, Guetta& Ahlers
16 PRLγ-ray spec
pp () follow the CR spectrum, assumed to be a power law.
minimal p () CR reservoirs such as galaxies and clusters, a spec
10-6
minimal p () break due to CR diﬀusion is naturally expected [14,the CR spectrum. However, it cannot be too hard
Fermi
Thus,
neutrino
spectrumis approximately
given
thethedecay
kinematics
of pions
gives nεν ∝ const
as a
IceCube"-7energy neutrino spectrum[39]. In minimal pγ scena
10ε2−s(εν b≤ εbν )νwhere εneutrinosεν ! εν ! 25 TeV(pp)are, prodν Qεν ∝ with
2−s′
b
ε
(ε
<
ε
)
ν
ν
by CRs at the pionν production
threshold, the neu
spectrum is approximately given by
10-8
where εbν is the breakenergy and the softening of
!
2
b
′
ε
(εν ≤ εfrom
spectrum, εδ Q
≡ s ∝− s, νis expected
thethe energyν)(minimal pγ) .
′
ν εν
2−s
b
pendence of the diﬀusionεν tensor(εν <[28].
εν ) In pp scenarios,-910
corresponding generated γ-ray spectrum is also a po
In theminimum
left panel ofpγ:
Fig. 1, we show the resulting
law ε−sinto the sub-TeV region (see Eq. (3)), wherγ
trino and
spectra withthe energy
diﬀuse neutrino~30γ-ray
TeV isarounddue
directly contributes
to justthe IGRB[29] and Ref.
[12]band the
IGRB[40] fora neutrino breakεν in the r
-10
to
the
pion
production
threshold10
tained a 8limits ! 2.1–2.2 for generic pp scenarios t
100 101 102 103 104 105 106 107 6–25
10 TeV. Since the sub-TeV emission is dominate
γ rays from cascades in the CMB and EBL, the ten
E [GeV]
with the IGRB can be weaker than in pp scenarios. H
ever, theγ-ray
IGRB contribution
is still at
If γ-ray transparent → strong tensions w. diffuse
bkg. for bothppthe&levelpγ of ∼bb
for εν = 25 TeV and reaches ∼ 100% for εν = 6 TeV
pp → ~100% of diffuse γ-ray bkg. even w. s~2.0
The spectrum (5) cancontrary
be realizedto
when
the target
standard
ton spectrum
is a powerAGN
law witha high-energy cuto
interpretation!
minimal pγ → >50% diffuse γ-ray bkg. (via EM
cascades)a gray body (see below). We note that specific m

Beyond Waxman-Bahcall?: Low-Energy “Excess” Problem

E2  [GeV cm-2 s-1 sr-1]• Best-fit spectral indices tend to be as soft as s~2.5• 10-100 TeV data: large fluxes of ~10 GeV cm s sr

-

the
BL
ertal
m 2
ted
in
xes
nsin
ote
ion
by

Implications of Detailed Gamma-Ray Studies

total integrated flux from point sources is 2.07+0.40
0.34 ⇥
+16
9
2
1
1
10 -6
ph cm s sr which constitutes
86 14 %fromof theblazars~100 % come10
EGB above 50 GeV estimated inThis validates
theat[2].
sub-TeVenergies?
predictions of models [3, 4, 12]. Point sources with fluxes
9
S > 1.3⇥ 10 12 ph cm 2 s 1 produce 1.47+0.20
ph0.24 ⇥ 10+2.0
cm 2 s 1 sr 1 , while 6.0 1.0 ⇥ 10 10 ph cm 2 s 1 sr 1
is produced
by sources below that flux.
-7
10
The Fermi-LAT has measured the angular power specSpectrum(Ackermann etatal. |b|
2014b)
trum of the di↵useEGB-ray
background> 30 and infour energy bins spanning
the 1-50 GeV energy range [19].
EGB Foreground modeling uncertainty
For multipoles l 155 the angular power CP is found to
Blazars - this work
be almost constant,Allsuggestingthat the anisotropy is pro-8
10 by an unclustered population of unresolved point
duced
All Blazars (no EBL) - this work
sources. Indeed, Refs. [20, 21, 22] argue that most of
the angular power measured by the Fermi-LAT isAjello+
due to 15 ApJL
unresolved emissionof radio-loud active galactic nuclei.
3
-1
2
10
10
10
1
10
Fermi Collaboration 16 PRL
The angular power due tounresolved sources at
Energy[GeV]>50 GeV can be readily predicted from the source count
EGB Spectrum (Ackermann et al., 2014b)
distribution as:
Sum of components
Photonfluctuation analyses(Poisson term of angular power spectra)
All Blazars - this work
10-6Z Smax
dN
2
CP =
(1 !(S 0 )) S 02 0 dS 0 [(ph cm 2 s 1 ) sr 1 ], Non-blazar contribution < 14±14%
dS
0
(4)

-2

E2dN/dE [GeV cm s-1 sr -1]

is
er11
,
.12
ion
eve
ion
unt
ity

FIG. 5: Comparison between the pixel count distribution from the average of 20 simulations (blue points), andthe distribution from the real sky (red points).
The
green points show the di↵erence between the two distributions. In each number of photon bin Nphotons ranging between [Nphoton,1 , Nphoton,2 ] we display–N
15pixel– with Nphotons 2[Nphoton,1 , Nphoton,2 ).

m-2 s-1 sr -1]

ith
eored
wn
s of

map
of one simulation (real sky) in the energy range 50 GeV-2
sedImplications of Detailed Gamma-Ray Studies
Our conclusion has been confirmed by subsequent papers

Bechtol+ 16 ApJ

shot-noise in diffuse γ-ray bkg.

Ando+ 15 PRL

cross corr. between galaxy catalogues

Given that IceCube’s data above 100 TeV are explained…
Decomposition of extragalactic γ-ray bkg. gives tighter limits: s<2.0-2.1
Insufficient room for pp scenarios to explain the 10-100 TeV neutrino dataImplications of Detailed Gamma-Ray Studies
Our conclusion has been confirmed by subsequent papers
10-5
E2  [GeV cm-2 s-1 sr-1]

Xiao, Meszaros, KM & Dai 16 ApJ(see also Wang & Loeb 16)

KM & Waxman 16

10-6
10-7

Fermi

pp 

Auger

IceCube

pp 

CR

-8

10

cosmogenic 

10-9

cosmogenic 

10-10 0
10

10

2

10

4

6

10
E [GeV]

8

10

10

10

- This conclusion is driven by the interpretation of 10-100 TeV data
could be alleviated by possible high-z only contributions- The model (s=2.0) in MAL2013 does not contradict the Fermi data(non-blazar EGB is well-explained by combination w. cosmogenic γ!)- But galactic CR production should be dominated by super-Pevatronsκpγ(Model
σpγ ∼ B),
10 althoughcmAγ
σpγ = κpγ σpγ ∼ 10cm
pγ =B segments,
jet model nofσRef.
[21]
−α
∝
ε
,
where
α
≥
2/3
[43].
For
n
∝
εt
εp
t
−25
esε−s
arecr predicted
tobeopaque scales
to very-highα−1where σT ≃ 6.65 × 10
cm2 and η(α)′ ′≃ 7
and
α
"
1,
the
eﬃciency
as
f
∝
ε
,
and
pγ
E
p
p
γε ≈ m5/3
ys.theTheright spectral
panel ofindex
Fig. 1is shows
corre(1 + α)] for 1 < α < 7 [44], whichis thneutrinos = scrthe+1−α.
For α !1)/[6α1 weeﬀ typical γ-ray energy
2-flavorandthegenerated
γ-ray spectra
der toof 0.1. The
given
byhave sneutrino∼ scr above
pion production
threshold dueσAγ= κAγ σAγ ∼ 10−27 iscm
eﬀ
fPretending≈ nγ σAγ∆ trans-[41, 42]. Ae higherand thin
red lines.and
γ-rayAγresonances
multipion
production
eﬀ
f
≈
n
σ
2 2 4 −1
Aγ
γ
AγΓ∆
ε
≈
me c εtAGN).
+
dssimilarto• violationofthehigh-energy
IGRB
data.
scalingisobtainedforgray-bodyandmonochroγγγ → e e : unavoidable in1/2pγ sources (ex. GRBs,
matictarget photon42]. −2are
s of
IGRB
contributionof[34,
pγ scenarios
eﬀ spectra
3
fthe
≈
n̂
σ
r
≃
5.4
× 10 photon
L field′ relation [41,
pγ
BL
BLR
pγ
Eqs.
to the following
τγγ 4Now, inpγ scenarios,thetargetcan(6) and (8) lead
0.8 GeVbecomeevenstrongerby sameidentifying
addi- AD,46.5
τγγ ≈nγ (0.1σTE)∆γ ≈eﬀfrom escaping−27 into2
preventor
γ by
rays
the
sources.
The
optical"#sourcesdecomposingtheemission
σ
=
κ
σ
cm
−28
Aγ
Aγ
2 ∼ 10
Aγ
+
−
σ
f
(ε
)
where
σ̂
∼
0.7
×
10
cm
is
the
attenuation
cross
depth
to
γγ
→
e
e
is
given
by
γγ
pγ
eﬀ γ-ray escape−27
2 pγ pc• Sametargetphotons This
prevents fromindividual
source populations.
τ
(ε
)
≈
f
(ε
)
≃
10
,
σ
=
κ
σ
∼
10
cm
γγ
pγ
p
γ
Aγ
Aγ
Aγ
ection(theproductoftheinelasticity
and
cross
secσ̂
0.01
pγ
constrain theτ γ-ray
transparent
sources ,for(ε(εt nεt )η(α)σ(8)
eﬀ T (r/Γ)
γγ
γ) ≈
ion
[41,
42]),
r
is
the
emissionradius,Γ is the bulk
0.1σγγfpγ ≈ bynγtheσpγFermi∆ anddataeV, which are still allowedcτ≈fpγ corresponding∼ 1000fpγ
γγ γ-ray eﬀ′dN′CR
energyto 0.05
theLorentz factor of the source.
The energy
of protonswherethat εγ is the
−25
2
σ
E
ε
≈
nelwhereof Fig.
other
hand,
since
the
σT 1).
≃ On
6.65τthe
×
10
cm
and
η(α)
≃
7(α
−
ν
pγ
∝
E
≈ nγ (0.1σ)∆ εt is nance proton energy satisfying Eq. (7), dEγγphotons
ypically5/3
interact with
withTenergy
issioncascades1)/[6αis dominated(1 + α)] forby1 γ<rays
α <from
7 [44],
which is the orτ ≈ n2m
0.1. The
typicalis givenby
B der
andofEBL,
tensionγ-ray
with2energy
the2 IGRB−1 can$ ε%γ (0.1σ
2 2 T )∆
εthe,(7) γγ ccp ≈ 20εν ≈ 0.5Γ mp c ε̄∆ εt
νeeﬀ to pp scenarios if the−28
2axed comparedsources
εγ ≈
εp !
∼ GeV
fpγ
0.01 25 TeV .
σpγ= εκpγσcm
2 2∼4 10
−1
pγ
m
ε̄
≈
Γ
m
c
ε
.
(9)
p ∆
γ rays generatedti.e. ifε̄∆high-energy
in therequire x0.1σ∼γγ30e TeV
where∼ 0.3 GeV, γandneutrinos
! ′ ′
τ
≈
f
∼
1000f
γγ
pγ
pγ
ﬀuse
neutrinos
undergoeﬃcient
interactions∆
E γγ ε[5]30neutrino
TeV-3 PeVν constrains
1-100
ayEqs.
or MeV
γ-ray
photons.
We hereconsidertraneﬀ
res(6) and(8) target
lead tothe following
relation[41, Thus,45], thedatafrom
25 TeVto
2.8GeV
PeV
σ
E
∼
0.1
TeV
cos
2θ
pγ
ν
urce radiation.
In fact, thisis generally
the pulsars,
relativisticor relativistic
sources,
like
0.1σ
responding
to γγ
the protonenergyrange from
" GRBs,#7.5∼×0.51
eﬀ
eﬀ
τ
≈
f
∼
1000f
scenarios
as
we
will
show
in
the
following.
σ
f
(ε
)
f
≈
(σ
/σ
)f
"
0.1
γγ
pγ
pγ
γγ
pγ
p
nd AGN
includingblazars,
wheretargetradiation
is
prepγ
Aγ
eﬀ
• Neutrino
production
bepγtooAγ
small the two-photoeﬀ∼fpγ
60 cannot
PeV,
can directly
constrainτγγ (εcγ ) ≈ fAγ
fpγ(εn
10 ∆ efficiency, to(10)≈σσp )γ ≃Aγpγ
σ̂pγsynchrotron or inverse-Compton
0.01
umably generated bynihilation optical depth at εγ ∼ 1–100 GeV.
f!
0.01
mission1.fromthermalor nonthermal
The lowpγ (requiringelectrons.
<<
1 unnaturalfine tuning),
In general, the eﬀective pγ optical depth fpγ
c fpγAND
CTING
pγ
γγ
OPTICALDEPTHS
where
ε
is
the
γ-ray
energycorresponding
to
the
resoγ
nergy photon
spectrum
canthebe observed
expressedCR
by flux
power-law
Do notovershoot′pends on source models. But too Esmall
d values
6o(nance proton energy
Eq. (7),
≈
0.8
Ge
1/2
−α satisfying
γ
eﬀ
−2
≃
10
τ
/m
"
egments,
n
∝
ε
,
where
α
≥
2/3
[43].
For
n
∝
& TakamiPRD)
εt 5.4t ×
εp Murase,[1] seem
K.
Phys.since
Rev.
Lett.
103, 081102(2009).
σ−srBLR(Yoshida≃
10 14
LAD,46.5
unnatural
theobserved
neutrino
flux i
eﬀ
−27
2
pγ
f
!
0.01
τ
!
10
E
pγ
α−1
γγ
cr
nsiderageneric
sourcewithtargetphotons
σ
=
κ
σ
∼
10
cm
$
%
2
2
and
α
"
1,
the
eﬃciency
scales
as
f
∝
ε
,
and
Aγ
Aγ 2me cAγpp far from the Waxman-Bahcall [46, 47] and nuc
εenergy
2. Comparison
w. non-thermal
ν pγ
c
eﬀ
eﬀ
ε
≈
.
ε
∼
GeV
and
spectrum
n
.
For
soft
targetspectraε≈he neutrino
spectral
s Aγ
= s)f
+1−α.
For α !survival
1(11)
we
γf
t indexcrAγ(σ p is/σ" 0.1
budgetsofbounds [48], corresponding to maximallypγm25 TeVp ε̄known∆ pγ objects
with sα∼>scr
1,
which
is
valid
in
most
nontherhave
above
the
pion
production
thresholddueto(galaxies, AGN, cluster shocks etc.)
cient neutrino production in the sources of ultra
meson
productionisdominatedbythe∆higherandmultipion[41, [5],42].
A (UHE) CRs. More quantitatively, it is pos
Thus,resonances
the neutrino
datafrom 25 production
TeV to 2.8 PeV
corenergy

pγ/γγ Optical Depth CorrespondenceIndication of Gamma-Ray Dark Cosmic-Ray Accelerators
4

Fermi-LATlog() or log(fp)

3



2
1

power law (=2.5)
power law (=2/3)
gray body & CR boundon  annihilation

0
-1

fp

-2

 & CR boundon p interaction-3-4

KM, Guetta & Ahlers 16 PRLp/ optical depth correspondence

-3

-2

-1

0

1

2
3
4
log( [GeV])

5

6

7

8

• Βounds on τγγ hold for both thermal and nonthermal photon targets• pγ mechanism: ν sources should naturally be obscured in GeV-TeV γ rays

GRBs and AGN as Hidden Neutrino Factories?

P H Yjets)
S I C A L RSupermassive
EVIEW LETT
ERS
blackholecores
RL 111,Low-power
121102 (2013)GRBs (choked

E2  [GeV cm-2 s-1 sr-1]

should be decelerated by photons v
thermal electrons and protons [28]. A
one no longer expects a strong sha weak subshock may exist [29]collisionless shock, and the shockby the deceleration scale
10
Kimura, Ml
1:5 # 105 cm n"1y"1+ when the co
u;19
-5
10
upstream flow lu is longer than ld
Low-Power
GRB (prompt)
G. 1 (color online). The
schematic
picture of a collimated
Low-Power GRB (orphan)
upstream proton density, and y+ ð, 1Þ
10-6 a progenitor. CR acceleration and HE neutrino
RB jet inside
IceCube 2015of pairs entrained or produced by theoduction may
happen at collimationand internal shocks. The-7
10
In the conventional shock acc
cture of the radiation-mediated shock is also shown.
-8
injected at quasithermal energies
10yond which
the cylindrical, collimated flow has a conradius of CRs with )!2rel mp c2 is ruL
10-9
"1=2
ant Lorentz factor (with !cj ! !"1j ) because of the fluxLrs;10 !2 !2rel ,3:8 # 10"3 cm &"1=2
-10
B
0;52
10
nservation.
The subsequent jet head position rh is
netic field, !rel is the relative Loren-11
10
LB =L0 [32]. If the velocity jump of t
3
4
105 1=5 106
107 "4=5108"1=5
rh ! 8:010# 10910cm t3=5
L
ð!
=0:2Þ
%
:
(2)
j
a;4
j0;52 KM
E [GeV]ru , the CR acceleration
is inefficient.
& Ioka 13 PRL
see also:
see also:L
Kimura, KM & Toma 15 ApJ
Senno, KM & Meszaros 16 Steckersignificant
Bhattacharya+ 15
deceleration occurs over13
ven
if the jet achieves ! & !cj in the star, !cj !
Nakar 15
cf. KM+ 06 ApJL
Kalashev+
15
immediate
upstream [28,29], CRs w"1
Waxman-Bahcall boundSummary
CR reservoirs are promising multi-messenger sources
Nice features: theoretical predictions including a multi-PeV break
UHECRs may be explained simultaneously
Even the diffuse γ-ray bkg. can be explained (grand-unification)
Strong predictions that can be tested (KM, Ahlers & Lacki 13)
1. s<2.1-2.2
2. >30% to the diffuse sub-TeV γ-ray bkg.
3. IACTs should observe them as hard γ-ray sources
Source identification is possible w. IceCube-Gen2 (stacking, event clustering)

Understanding the 10-100 TeV data is important
LE excess: fluctuation? magical combination w. Gal. comp.? or new physics?
pp scenarios: most models suffer from tensions w. the diffuse γ-ray bkg.
pγ scenarios: hidden CR accelerators needed & tensions are naturally avoided
X-ray/MeV γ-ray counterparts (ex. low-power GRBs/AGN)
Are cosmic-ray connections just coincident?

Thank You!