NOW 2010 NOW 2010

Kohta Murase Kohta Murase (Center for Cosmology and AstroParticle Physics, (Center for Cosmology and AstroParticle Physics,

Ohio State University, USA)Ohio State University, USA)

High-energy neutrinos from High-energy neutrinos from extragalactic cosmic-ray sourcesextragalactic cosmic-ray sources

OutlineOutline

Overview of HE s from extragalactic sources

• Gamma-ray bursts

• Active galactic nuclei & clusters of galaxies

• Newly born magnetars emission from sources of UHE nuclei

Neutrinos as a MessengerNeutrinos as a Messenger

Purposes: • Origin of cosmic rays (CRs)• Source properties (jet contents, magnetic field etc.)• Clues to acceleration mechanisms

GeV-TeV gamma-ray obs.:・ attenuation in sources and/or CMB/CIB・ contamination by leptonic emission

HE-neutrino obs. (>0.1TeV):・ more direct probe・ neutrino physics (e.g., oscillation)

•Neutrinos produced outside a source (e.g., cosmogenic) (->Stanev, Olinto)•Neutrinos produced inside a sourceIn this talk, we focus on the latter €

γ+γCMB/CIB → e+ + e−

Extragalactic Cosmic-Ray AcceleratorsExtragalactic Cosmic-Ray Accelerators

Hillas condition E < e B r E>1020eV, Z=1

→ LB≡BL > 1047.5 erg/s 2 -1

UHECR source candidatesThe most extreme objects!

GRB

AGN jet

clusters

r

B

AGN

GRBs

Clusters

The most massive BHMBH~106-9Msun

The brightest explosionEGRB~1051ergs

The largest grav. obj. rvir ~ a few Mpc

MagnetarsThe strongest mag. fields

B ~ 1015 G

magentars

マスタ サブタイトルの書式設定

5

Gamma-Ray Bursts

(Long) Gamma-Ray Bursts(Long) Gamma-Ray Bursts

•The most violent phenomena in the universe (Lγ~1051-52 ergs s-1)•Cosmological events (z~1-3)•~1000 per year (⇔ ~ 5 yr-1 Gpc-3 @ z~1)•Relativistic jet (~300; γ ~ 1051 ergs ~ 0.01 γ,iso, jet ~ 0.1 rad)•Related to the death of massive stars (association with SNe Ic)

Gamma-ray ～ 300 keVDuration ～ 10-103s

Prompt (GRB)Afterglow

X-ray 、 optical 、 radio

variability~ ms

Time

Luminosity

10-102s103-104s

Prompt emissionPeV ν, GeV-TeV γ

(Waxman & Bahcall 97 PRL)(KM et al. 06 ApJL)

Meszaros (2001)

•emission radius ~ 1013-1015.5 cm•mildly relativistic shocks•magnetic field ~102-105G

Orphan emission TeV ν, no γ

(Meszaros & Waxman 01 PRL)(Razzaque et al. 03 PRL)(Ando & Beacom 95 PRL)

Basics of Neutrino EmissionBasics of Neutrino Emission

€

p+ γ → n + π + κ p ~ 0.2

εp

CR Spectrum (Fermi mechanism)

Key parameterCR loading

1018.5eV1020.5eV

εγ

Photon Spectrum (observed)

εγ,pk~300 keV εmax

Photomeson production efficiency~ effective optical depth for pγ process

fpγ ~ 0.2 nγσpγ (r/Γ)

Δ-resonance at Δ-resonance

εp εγ ~ 0.3 Γ2 GeV2

εpb~ 0.15 GeV mpc2 Γ2/εγ,pk ~ 50 PeV

εp2N(εp)

2-α~1.0

2-β~-02-p~0

~ΓGeV

εγ2N(εγ)

EHECR≡εp2N(εp)

~εγ,pk2N(εγ,pk)

multi-pion production

Photomeson Production

€

p+ γ → Nπ ± + X κ p ~ (0.4 − 0.7)

(in proton rest frame)

total ECR~20EHECR

pion energy επ~ 0.2 εp

break energy επb~ 0.07 GeV2 Γ2/εγ,pk ~ 10 PeV

επ

Meson Spectrum

επｂ επ

syn

β-1~1

α-1~0

επ2N(επ)

Neutrino Spectrum

ενb

β-1~1

α-1~0

εν2N(εν) )(→

)()(e→ ee

0:2:1::e

meson cooling before decay(meson cooling time) ~ (meson life time)→ break energy in neutrino spectra

Neutrino oscillation

~fpγEHECR

α-3~-2.0

meson & muon decay

“Waxman-Bahcall” type spectrum (Waxman & Bahcall 97 PRL)

ενμsyn εν

πsyn

εν

α-3~-2.0

neutrino energy εν ~ 0.25 επ ~ 0.05 εp 　

•ν lower break energy ενb ~ 2.5 PeV

•ν higher break energy ενπsyn ~ 25 PeV

μμee±

μμ±± ν+ν+)ν(ν+e→)ν(ν+μ→π

1:1:1::e

8.1:8.1:1::e

No loss

High εν

Loss limit

pγ process(Kashti & Waxman 05 PRL)

GRB PromptGRB Prompt

●Meson production efficiency is rather uncertain mainly due to r and ●~0.1-10 events/yr by IceCube (w. moderate CR loading)●Testable case: GRB-UHECR hypothesis/Hadronic model for Fermi GRBs

IceCube is constraining optimistic cases (Becker’s talk, Kappes arXiv:1007.4629)

moderate CR loadingEHECR ~ 0.5 EGRBγ

(Up=10Uγ)

high CR loadingEHECR ~ 2.5 EGRBγ

(Up=50Uγ)

CR loading parameterΕHECR ≡εp

2 N(εp)

Set A - r~1013-14.5cm Set B - r~1014-15.5cm

Γ=102.5, Uγ=UB

KM & Nagataki, PRD, 73, 063002 (2006)

Event rates by IceCube for 1 GRB @ z~1 ~ 10-4-10-2

→ Cumulation of many GRBs (time and space coincidence) see also Dermer & Atoyan 03 PRL Guetta et al. 04 APh Becker et al. 06 APh

Alternative Scenario?Alternative Scenario?

• Internal shock model has problems in explaining observations • Prompt emission may be quasi-thermal rather than nonthermal

(e.g., Thompson 94, Rees & Meszaros 05, Ioka, KM+ 07)

γ-ray emission from =ne(r/)~1-10 ⇔ pp~ 0.1-1

GeV-TeV neutrinos due to pp

•Efficiency is almost fixed •Detectable for smaller EHECR

•Detectable even if proton acceleration is inefficient•UHECRs are not produced

Γ=102.5, Uγ=UB

EHECR=1051 erg

KM, PRD(R), 78, 101302 (2008)Wang & Dai, ApJL, 691, L67 (2009)

pp

pγ

Early AfterglowsEeV ν, GeV-TeV γ

(KM & Nagataki 06 PRL)(Dermer 07 ApJ)

(KM 07 PRD)

Meszaros (2001)

Classical AfterglowsExternal Shock Model

EeV ν, GeV-TeV γ (Waxman & Bahcall 00

ApJ)(Dai & Lu 01 A&A)(Dermer 02 ApJ)

•emission radius ~ 1016-1017cm•mildly relativistic reverse shock& ultra-relativistic forward shock•magnetic field ~0.1-100 G

GRB Early AfterglowGRB Early Afterglow

ES protons + ES opt-x rays Stellar Wind Medium

(normalized by UHECR budget)

Late IS protons + flare x rays(normalized by 10% of UHECR budget)

KM, PRD, 76, 123001 (2007)

ES protons + ES opt-x rays Inter Stellar Medium

(normalized by UHECR budget)

KM & Nagataki, PRL, 97, 051101 (2006)

• Flares – efficient for meson production (fpγ ~ 1-10) and detectable • ES – not easy to be seen by both neutrinos and gamma rays

•Afterglows are explained by the external shock model•Proton acceleration is possible during afterglows analogous to in SNRs

•Many GRBs accompany energetic flares during afterglows

Active Galactic NucleiActive Galactic Nucleiandand

Clusters of GalaxiesClusters of Galaxies

Active Galactic NucleiActive Galactic Nuclei

•Super-massive black holes (M~106-9 Msun)•Accretion onto a BH (accretion disk) and relativistic jets (~3-30)•Beamed nonthermal emission from inner jets -> blazar emission•AGN w. powerful jets -> radio galaxies (Fanaroff-Riley I&II)•~1% of AGN have hot spots as well as lobes (Fanaroff Riley II)

jet BH

accretion disk

dust torus

CR and CR and Production in AGN Production in AGNInner jet (blazar; FRI/II) (c.f. prompt)

r ~ 1016-1017 cm B ~ 0.1-100 G

Hot spot, Cocoon (FRII) (c.f. afterglow)

r ~ 1021 cm B ~ 1 mGr ~ 1022 cm B ~ 0.1 G??

Emax ~ Eesc ~ 1020-21 eVe.g., Biermann & Stritmatter 87 ApJ Takahara 90 PTP Rachen & Biermann 93 A&A Berezhko 08 ApJL

Emax ~ Epγ <~ 1017-20 eVneutron conversion?

e.g., Biermann & Stritmatter 87 ApJ Mannheim+ 92 A&A Atoyan & Dermer 01 PRL

＊ Core (disc/vicinity of BH) (c.f. orphan)

optimistic cases (no UHECRs) Stecker+ 91 PRL, Protheroe & Szabo 92 PRL

Neutrinos and Gamma Rays from BlazarsNeutrinos and Gamma Rays from Blazars

Mucke et al. 02

Low-peak

High-peak

X-ray GeV γ TeV γIR,optical

HE

•Lower-peak blazars tend to have larger luminosities•Lower-peak blazars → efficient ν (and γ) production (~ EeV neutrinos) (On the other hand, UHECR survival is more difficult due to pγ)

Neutrino spectrumObserved Photon Spectrum

Mucke+ 03 APh

Low-peak BL Lac

High-peak BL Lac

HE emission can be explained by the hadronic model as well as leptonic model

(e.g., Mannheim 93, Aharonian 02, Mucke+ 03)

This scenario requires high CR loading, LCR >~ Lrad

Contd.Contd.

Jet+Disk

jet

Jet only

N ~ 10-3

N ~ 0.1-0.4

s from blazars may be seen by seed photons from acc. disc(but UHECRs are depleted c.f. GRB flares)

Atoyan & Dermer 01 PRLAtoyan & Dermer 03 ApJ

AGN JetAGN Jet

•Various models from different motivations •Core/Blazar-max. (norm. @ MeV/>0.1GeV) are being constrained•Norm. by UHECRs for typical BL Lacs → < 0.1-1 events/yrBut we will be in the interesting stage

Core(Stecker 05) BL Lac jet

(Mucke+ 03)

Blazar-max. jet(Mannheim+ 01)

FRII jet(Becker+05)

Becker 06 PhR

KM 08 AIPC

Cen A (Non-Blazar)Cen A (Non-Blazar)

• Cen A: nearest AGN (FRI) @ ~3 Mpc• Apparently correlated with UHECRs observed by Auger• UHECR source? (e.g., Gorbunov+ 08, Sigl 09, Hardcastle 09, Gopal-Krishna+ 10)

Acc. sites•Core/inner jet•Possible hot spots•Lobes

But s from inner jets are off-axis emission•pγ in core•pp in extended high-density region→ < a few events/yr(Cuoco&Hannestad 08 PRD Kachelriess+ 09 NJP 09)

But, then Cen A should be particular (Koers & Tinyakov 08 PRD )

Kachelriess+, NJP, 76, 123001 (2009)

(Biermann’s talk)

AGN and Clusters of GalaxiesAGN and Clusters of Galaxies

•Clusters of galaxies contain AGN•The largest gravitationally bounded objects (M~1014-15 Msun, r ~ Mpc)•Cosmic-ray storage room (AGN, Galaxies)•Structure formation shocks (matter accretion, cluster mergers)CRs interact with intracluster gas via pp(Berezinsky+97 ApJ, Colafransesco & Blasi 98 APh)

CRs interact with rad. field via pγ(De Marco+ 06 PRD, Kotera, Allard, KM+ 09 ApJ)

>30 PeV CRs lead to >PeV s

AGN and ClustersAGN and Clusters

KM, Inoue, & Nagataki, ApJL, 689, L105 (2008)

•Norm. by HECRs above 1017.5 eV → a few events/yr (>0.1PeV)γs are cascaded ⇔ can be consistent with Fermi γ-ray bkg.

all the flavorsEb=1017.5 eV

Kotera+, ApJ, 892, 391 (2009)

pp

pγ

マスタ サブタイトルの書式設定

23

Newly Born Magnetars

MagnetarsMagnetars

Corr. w. spiral galaxies → magnetar or GRB?Ghisellini+ 08 MNRAS, Takami+09 JCAP

•Neutron stars with the strongest magnetic fields (B~1015 G>1012G)•Giant flares (Eflare~1044-46 erg)•Slow rotation at present (period ~5-10 s) but maybe fast rotation at birth (period ~ ms)•Birth rate may be ~ 10 ％ of core-collapse SN rate

Production in Fast-Rotating MagnetarsProduction in Fast-Rotating Magnetars

(possible)jet

• UHECR acc. may occur in a cavity ~hrs after the birth (Arons 03 ApJ)

• Surrounded by stellar envelope

• Accelerated CRs interact with envelope and rad. Field

　　→ meson production

• Escape of UHECRs ？ e.g., puncturing envelope by jets → A fraction of CRs may produce

mesons in jets as in GRBs

naturally expected in the magnetar-UHECR scenario

NS

envelope

shock

wind

cavity

Fast-Rotating MagnetarsFast-Rotating Magnetars

• Expected muon-event rate ~ 1-10 events/yr• Rate detecting >1 s → ~ 0.1 yr-1 (useful for alerts)

Detectable for D<5MpcTime scale ~ daysoft-hard-soft time-evolution

Probe of the magnetar birth

KM, Meszaros, & Zhang, PRD, 79, 103001 (2009)

Neutrinos from Sources of Neutrinos from Sources of UHE NucleiUHE Nuclei

Proton or Nuclei?Proton or Nuclei?

• HiRes/TA -> proton composition Auger -> UHECRs are largely nuclei

• Hillas cond., E>1020 eV, Z=26 → LB > 1043.5 erg/s (2 -1

Much dimmer sources are allowed as UHECR sources

• Survival from photodisintegration (Aγ~nγ Aγ (r/ < 1) Photon and matter density should be small enough

• One can build scenarios where UHE nuclei can surviveGRBAGNClusters

Then, what is the consequence for detectability of neutrinos?

(KM+ 08 PRD, Wang+ 08 ApJ)

(e.g., Pe’er, KM, & Meszaros 09 PRD, Gopal-Krishna+ 10 ApJ)

(Inoue+ 07, see also Kotera, Allard, KM+ 09, ApJ)

Waxman-Bahcall landmarks (Waxman & Bahcall 98 PRD)

reasonable bounds of cumulative s from UHECR sources

assumption ： UHECR spectrum N(p) ∝p-2

meson production efficiency fpγ (< 1) → 1 “formal” limit

(fpγ ~ 0.2 nγσpγ (r/Γ))

flux 2 N () ~ 0.25 fpγ p2 N(p)

→ (0.6-3)×10-8 GeV cm-2 s-1 sr-1 Most theoretical predictions lie

under WB landmarks

IceCube reaches WB landmarks below MPR landmarks　

Landmarks from UHE Proton SourcesLandmarks from UHE Proton Sources

Landmarks from UHE Nuclei SourcesLandmarks from UHE Nuclei Sources

Nucleus-survival requirement Aγ nγ γ r < 1

res. approx. → fmes ~ (0.2/A) nγ A pγ (r/) ~ Aγ (0.2 pγ/Aγ) < 10-3

fAγAγAγ < 1 (most conservative)

*non-applicable to non-UHECR sources (e.g., KM+ 08 for exception)

2 N ()~0.25 fmes 2 N() < (0.4-2)×10-9 GeV cm-2 s-1 sr-1

KM & Beacom, PRD, 81, 123001 (2010)

SummarySummarys are expected for very powerful extragalactic CR sources

Various possibilities, of course many uncertaintiesSources may be seen if we are lucky -> big impacts!Some of the scenarios seem testable in the near future • GRB

prompt w. UHECR hypothesis (←CR loading must be large)Hadronic models for Fermi GRBs, flares…

• AGNblazars in the hadronic model, flares of GeV blazars, clusters of galaxies, specific models for Cen A…

• Magnetar

Especially for UHECR sources, if UHE nuclei such as UHE iron ubiquitously survive in sources, Aγ s would be difficult to see by IceCube

Grazie!

Thanks for organizers