High-Energy Neutrino Astronomy High-Energy Neutrino Astronomy and and Gamma-Ray Bursts Gamma-Ray Bursts Kohta Murase ( Kohta Murase ( 村村 村村 村村 村村 ) ) (Yukawa Institute for Theoretical Physics, (Yukawa Institute for Theoretical Physics, Kyoto University) Kyoto University) Collaborators: S. Nagataki, K. Ioka, T. Nakamura, F. Iocco, S.D. Serpico, T. Koi, H. Takami, K. Sato, K. Asano, S. Inoue
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High-Energy Neutrino Astronomy and Gamma-Ray Bursts Kohta Murase ( 村瀬 孔大 ) (Yukawa Institute for Theoretical Physics, Kyoto University) Collaborators:
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High-Energy Neutrino AstronomyHigh-Energy Neutrino Astronomyand and
Gamma-Ray BurstsGamma-Ray Bursts
Kohta Murase (Kohta Murase ( 村瀬 孔大村瀬 孔大 ))(Yukawa Institute for Theoretical Physics, (Yukawa Institute for Theoretical Physics, Kyoto Kyoto
University)University)Collaborators: S. Nagataki, K. Ioka, T. Nakamura, F. Iocco, S.D. Serpico, T. Koi, H. Takami, K. Sato, K. Asano, S. Inoue
OutlineOutline
Future Prospects for High-Energy GRB Neutrinos
1. Introduction
2. Prompt Neutrino Emission
3. Other Predictions
4. Implications of the GRB-UHECR Hypothesis
5. Summary
マスタ サブタイトルの書式設定
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Introduction
Why Neutrinos?Why Neutrinos?
• Astrophysical MeV Neutrinos
Solar neutrinos / Supernovae (SN1987A)
Probe of stellar physics (core / core collapse)
• Astrophysical >0.1 TeV Neutrinos
SNRs, GRBs, AGN, cluster of galaxies…
Probe of CR acceleration (pp/pγ)
CRs → ○ direct probe of CRs ×impossible except for UHECRsγs → ○ easily detected ×contamination by leptonic components νs → ○ good proof of CRs ×difficulty of detection
Cosmic-Ray SpectrumCosmic-Ray Spectrum
Knee ~ 1015.5 eV
2nd Knee ~1017.5 eV
Ankle ~ 1018.5 eV
Problems!•What is the source?•What is origin of breaks?•Composition?•Anisotropy?• • •
•How are CRs accelerated?
What Is the source of CRs?What Is the source of CRs?
)( )101~(eBc
pacct -
coolacc tt •Acceleration vs Loss/Escape should be considered
If diffusive → spectral index p ~ 2 (p~2.2 for Γ→ ∞)
shock
v1 > v2
Shock acceleration
Physics of particle acceleration is not well understood → need more studies
•amount of accelerated particles?•Amplification of magnetic field over large scales?•Diffusive?, or large-angle scattering rather than small-angle scattering? •Other acceleration mechanisms such as 2nd order Fermi acceleration?
ν detection → implications for the source physicsamount of CRs, implications for B, etc.
baryonic (e.g., fireball) vs non-baryonic (e.g., magnetic) ?
Large Neutrino TelescopesLarge Neutrino Telescopes
taken from IceCube homepage
IceCube IceCube (Antarctica)(Antarctica)
Km3 ice Cherenkov ANTARES
taken from ANTARES homepage
KM3Net KM3Net (Mediterranean(Mediterranean ))Km3 water Cherenkov
direction reconstructed from correlations between PMTs
106 muons from cosmic rays/muon
from neutrinos
Select only muons from
below
Select only muons from
below
•ν-induced cascade•τ double-bang etc...
Other signals
Water or Ice Cherenkov detectors
•e.g., Radio detection (RICE, ANITA, ARIANNA)e.g., Radio detection (RICE, ANITA, ARIANNA)•Detection of air showers from earth skimming νDetection of air showers from earth skimming νττs (PAO, TA, Ashra)s (PAO, TA, Ashra)
Afterglows Ep,max ~ ZeV
EeV ν, GeV-TeV γ
Prompt EmissionEp,max ~ EeV-ZeV
PeV ν, GeV-TeV γ
Below Photosphere
Ep,max ~ PeV-EeV
TeV-PeV ν, invisible γ
Meszaros (2001)
Flares/Early AfterglowsEp,max ~ EeV
PeV-EeV ν, GeV γ
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Prompt Neutrino Emission
Prompt Emission from Classical (High-Luminosity) GRBs
Internal Shock ModelPeV ν, GeV-TeV γ
(Waxman & Bahcall 97)
Meszaros (2001)
Classical AfterglowsExternal Shock Model
EeV ν, GeV-TeV γ (Waxman & Bahcall 00)
(Dai & Lu 01)(Dermer 02)
(Li, Dai & Lu 02)
Prompt Neutrino EmissionPrompt Neutrino Emission
2.0~κπ+n→Δ→γ+p p+
εp
Cosmic-ray Spectrum (Fermi)
Key parameterCR loading
1018.5eV1020.5eV
εγ
Photon Spectrum (Prompt)
εγ,pk~300keV εmax
Photomeson production efficiency~ effective optical depth for pγ process
fpγ ~ 0.2 nγσpγ (r/Γ)
Δ-resonance Δ-resonance approximation
εp εγ ~ 0.3 Γ2 GeV2
εpb~ 0.3 Γ2/εγ,pk ~ 50 PeV
εp2N(εp)
2-α~1.0
2-β~-0.22-p~0
~ΓGeV
εγ2N(εγ)
EHECR≡εp2N(εp)
~εγ,pk2N(εγ,pk)
multi-pion production
Photomeson Production
)7.04.0(~κX+πN→γ+p p± -
(in proton rest frame)
Δ-resonance approximationpion energy επ~ 0.2 εp
break energy επb~ 0.06 Γ2/εγ,pk ~ 10 PeV
επ
Meson Spectrum
επb επ
syn
β-1~1.2
α-1~0
επ2N(επ)
Neutrino Spectrum
ενb
β-1~1.2
α-1~0
εν2N(εν) )(→
)()(e→ ee
meson cooling before decay(meson cooling time) ~ (meson life time)→ break energy in neutrino spectra
Neutrino oscillation(Kashti & Waxman 05)
~fpγEHECR
α-3~-2.0
meson & muon decay
“Waxman-Bahcall” type spectrum (Waxman & Bahcall 97, 99)
ενμsyn εν
πsyn
εν
α-3~-2.0
Δ-resonance approximationneutrino energy εν ~ 0.25 επ ~ 0.05 εp
・ Much dimmer than usual GRBs (ELL,γ ~ 1050 ergs ~ 0.001 EGRB,γ)
・ LL GRBs (e.g., XRF060218, GRB980425) more frequent than HL GRBs local Rate ~ 102-3 Gpc-1 yr-3
(Soderberg et al. 06, Liang et al. 07 etc…)
If true → contribution to (UHE)CRs & νs
Liang et al. (07)
dark bright
Luminosity
•Prompt ν emission (KM et al. 06, Gupta & Zhang 07) ~1 event from a LL GRB at 10 Mpc•Interaction with the thermal component (KM et al. (06), Yu, Dai, & Zheng (08)) ~(0.01-1) event from a LL GRB at 10 Mpc
Rate
2. Flares in the early afterglow phase (Chincarini’s talk)
Approaches to GRBs through high-energy neutrinos LL GRBs→a possible indicator of SNe Ibc associated with LL GRBsFlares→information on flare models (baryonic or nonbaryonic etc.)
νs from LL GRBs → little coincidence with bursts, a few events/yrν flashes → Coincidence with flares/early AGs, a few events/yr
Flares (Eflare,γ = 0.1 EGRB,γ ) LL GRBs
(ELL,γ ~ 0.001 EGRB,γ )
HL GRBs
Gupta & Zhang (2007)
baryon loadingEHECR ~ 0.5 Eγ
KM, PRD, 76, 123001 (2007)
Below Photosphere
TeV ν
(Meszaros & Waxman 01)
(Schneider et al. 02)
( Razzaque, Meszaros, & Waxman 03)
(KM et al. 08)
Meszaros (2001)
Below/Around PhotosphereBelow/Around PhotosphereBelow/around the photosphere (even inside the star)CR acceleration could be expected
(c.f., Meszaros & Waxman 01, Razzaque et al. 03)
Below/around photosphere ⇔ small collision radius r(pp optical depth fpp) ~ 0.5 np σpp(r/Γ) >~ 0.1 → pp reaction important
r=1012.5 cmΓ=100, UB=0.1Uγ
strong meson/muon cooling ↓
kaon-contribution is important (Ando & Beacom 05,Asano & Nagataki 06)
Note: kaon-contribution is just roughly estimated in the left panel.
KM (08) Similar calculations are done by Wang, independently.
•Possible two Contributions (IS+TS)•Meson cooling is important (Razzaque, Meszaros, & Waxman 03)
•Spectrum becomes complicated
•Nearby events → ~(10-100) events
KM et al. (08)
The Cumulative Neutrino BackgroundThe Cumulative Neutrino Background
Iocco et al., ApJ (08), KM et al., in prep. (08)
Schneider et al. 02 (First Stars)
Precursor = successful GRBs (GRB rate)
(c.f. sub-photosphere νs)
•Possible choked-jet signals?Possible choked-jet signals?•choked νs → diffuse background •The AMANDAII limit implies (# of failed GRBs)/(# of SNe-Ibc) < 0.1 for EHECR ~ 0.5 EGRB
•Possible POPIII contribution?Possible POPIII contribution?•Schneider et al. (02) → overestimation•ν detection would be difficult, even if all the first stars can produce GRBs.
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Implications of theGRB-UHECR Hypothesis
Test of GRB-UHECR HypothesisTest of GRB-UHECR Hypothesis
3153
UHECRGpcyrergs~ 10E
-- ergs10E53
,GRB~
possible but requiring high baryon load… EHECR >~ EGRB,γ
(Swift-era lower local rates may lead to higher baryon load…)
•GRBs could be UHECR sources (Waxman 95, Vietri 95)•PAO → possible correlation with galaxies as well as AGN (e.g., Kashti & Waxman 08, Ghisellini et al. 08)
Gpcyr1 31HLGRB
--~
← Model predictions with UHECR-normalization (except for Late Prompt/Flare)
Strong evolution model → possible detection in the near future (see Yuksel & Kistler 07)
Takami, KM, Nagataki, and Sato (08)
Auger 07 limit
AssumptionEmax=1022eV
CMB+CIB(Best-fit model of Kneiske et al. 04)
νs generated outside the source by UHECR-CMB/CIB interactions
strong evolution∝(1+z)4.9 (z<1.2)
∝(1+z)0.2 (z>1.2)
normal evolution∝(1+z)3.5 (z<1.2)
∝(1+z)-1.2 (z>1.2)
no evolution∝(1+z)0
Thick: dip modelThin: ankle model
UHECR AstronomyUHECR AstronomyUHECR production may be possible in both of high- and low-luminosity GRBs
The source number density ← PAO, TA Burst Models → Sensitive to effective EGMF strength
(structured + intergalactic)Necessity of future observations and theoretical studies PAO results ~10-4 Mpc-3 → HL GRB marginally inconsistent
(Takami & KM 08)
(KM, Ioka, Nagataki, & Nakamura, PRD, 08)
HE CR acceleration → inevitable γ-ray emission (>TeV)
Internal attenuation due to pair-creationpγ ⇔ γγ (Waxman & Bahcall, PRL, 97, Dermer et al., ApJL, 07)
“Roughly speaking”… νbright (dark) ⇔ TeV γ dark (bright)
Nγ ⇔ γγ (KM, Ioka, Nagataki, & Nakamura, PRD, 08)
Survival of UHE heavy nuclei (e.g., Fe) → τγγ(TeV) <~ 1
•PAO → (tentative) existence of heavier nuclei (Unger et al. 07)
UHE nuclei → large r or Γ (even subdominant) TeV γ rays
•small r or Γ ⇔ ν bright, while TeV γs attenuated→ electromagnetic cascades & inevitable GeV γ rayslarge baryon loads → spectrum modification ⇔ GLAST (c.f., Dermer & Atoyan 04, Asano & Inoue 07)
CR-Induced Gamma-RaysCR-Induced Gamma-Rays
GRB-UHECR hypothesis could be tested in the future…
(see also, Wang et al., ApJ, 08)
SummarySummary• We can expect high-energy neutrino signals under the
internal/external shock models if jets are baryonicif jets are baryonic.
1. Prompt ν emission models (HL GRBs or LL GRBs) have been tested Prompt ν emission models (HL GRBs or LL GRBs) have been tested by AMANDA/IceCube.by AMANDA/IceCube.
2. Neutrino flashes (flares) and Neutrino flashes (flares) and neutrinoneutrino early afterglows early afterglows
3. Neutrinos from sub-photospheresNeutrinos from sub-photospheres
• Time- and space-coincidence (with Swift, GLAST etc.)Time- and space-coincidence (with Swift, GLAST etc.) → → more merits than other sources (clusters, AGN etc)more merits than other sources (clusters, AGN etc)
• A good probe of CR acceleration
• Non-detection → just constraints on models
• Detection → clues to GRB models and CR acceleration (poor statistics → importance of multi-messenger astronomy)
• The connection between GRBs and UHECRs will be tested
Waiting to detect extragalacticνs hopefully…Waiting to detect extragalacticνs hopefully… Thank you!
e.g., GZK mechanism εγ ~ 10-3 eV εp ~ 1020 eV εν~ 5×1018 eV
hadrons→pp
photodisintegration
nor p 1)-(A →A γGiant Dipole Resonance (GDR)
Important for survival of UHE heavy nuclei
Important for dense targets
Ep>>TeVHigh inelasticityHigh multiplicity
Other EffectsOther Effects•Effect of multi-pion production
2.2~βby a factor
by one order
For flatter photon spectra (α=0.5,β=1.5)
For typical photon spectra (α=1, β=2.2)
KM & Nagataki, PRD, 73, 063002 (2006)
•Effect of Kaon originated neutrinos
Asano & Nagataki (06)
•Effect of neutrino oscillation
νeνμντ=1:1:1
νeνμντ=1:1.8:1.8
e.g., Kashti & Waxman (05)
EeV neutrinos from Optical/IR FlashesEeV neutrinos from Optical/IR Flashes
Neutrinos can be detected only if we observe very strong optical/IR flashes (when the deceleration radius is small)! Lack of optical/IR flashes (and early-AG may not behave as expected)•Dust extinction? (Roming et al. 05). •Internal dissipation origin?•RS emission (thin ejecta) is fainter than earlier estimates (Nakar & Piran 04)•Suppression due to IC cooling (thick ejecta). (Beloborodov 05)•Highly magnetized flow (Zhang & Kobayashi 05, Luitikov 05)
990123 at z=0.1
z=0.1
KM, PRD, 76, 123001 (2007)
Neutrinos from LL GRBsNeutrinos from LL GRBsEx.) XRF060218-like burst•Prompt nonthrmal emission Epk ~ 5 keV
↑Internal shock model (e.g., Toma, Ioka, Sakamoto, & Nakamura 07)
•Prolonged thermal emission kT ~ 0.15 keV
KM, Ioka, Nagataki, & Nakamura, ApJL, 651, L5 (2006)
r/Γ2=fixed
D=10Mpc
Muon events ~ 1 event
Muon events ~ 0.1 event
See also Gupta & Zhang 07For early afterglowssee Yu, Dai, & Zheng (08)
Early Afterglow Neutrino EmissionEarly Afterglow Neutrino Emissionshallow decay
・ Forward Shock Model (energy injection etc.)・ Reverse Shock Model (Genet et al. 07, Beloborodov 07)
・ Late Prompt Emission Model (Ghisellini et al. 07)
Typically Eshallow,γ ~ 0.1 EGRB,γ (Liang et al. 07)• RS-FS model: ν-detection by IceCube would be difficult…• Late prompt emission model: ν-detection may be possible.
t
Its origin is still controversial...
Prompt
KM, PRD, 76, 123001 (2007)
high baryon loadingEHECR ~ EGRB,γ
fiducial baryon loadingEHECR ~ Eshallow,γ
~ 0.1 EGRB,γ
steep decay
(For forward shock νs,see Dermer 02, 07)
High-Energy Early Afterglow EmissionHigh-Energy Early Afterglow Emission
4. Neutral pion decay produced 4. Neutral pion decay produced by by photo-meson productionphoto-meson production
5. The contribution from 5. The contribution from electrons+positrons produced electrons+positrons produced by by photo-pair productionphoto-pair production