1. High Energy Neutrinos and Gamma-Ray Bursts Kohta Murase (YITP) S. Nagataki, K. Ioka, T. Nakamura K. Asano, S. Inoue, H. Takami K. Sato, F. Iocco, P.D. Serpico

2. Neutrinos as a Probe of Cosmic-Ray Acceleration Astrophysical Accelerators (GRB, AGN, Cluster of Galaxies … ) → cosmic-rays accelerated above TeV even up to ZeV Neutrinos → good evidence of cosmic-ray acceleration (Especially useful as a probe of ~100 PeV energy cosmic-rays) pp/ pγ → π, K → ν, γ pp/pγ reaction GRB (talk by Prof. Meszaros) Merits! - time and position coincidence Testing the shock model (baryonic or not?) Magnetic field/amount of baryons The origin of observed UHECRs? taken from IceCube homepage km3 telescopes (IceCube/KM3Net) Various model predictions have become testable Cosmic-rays → Deflection by magnetic fields (talk by Dr. Takami) Gamma-rays above TeV → Attenuation by CMB and CIB (talk by Dr. Asano)

3. Plan of Talk Model-Predictions for High-Energy Neutrinos from Astrophysical Sources 1. Neutrino Emission & Gamma-Ray Bursts a. Pre-Swift Predictions (Prompt Emission) b. Swift-Era Predictions (Flares and so on) c. Neutrinos and Progenitors 2.Connection between Astrophysical Neutrino Sources and High-Energy Cosmic-Rays

4. マスタ サブタイトルの書式設定 4 Gamma-Ray Bursts

5. Afterglows E p,max ~ ZeV EeV ν, GeV-TeV γ Prompt Emission E p,max ~ EeV-ZeV PeV ν, GeV-TeV γ Below Photosphere E p,max ~ PeV-EeV TeV-PeV ν, invisible γ Meszaros (2001) Flares/Early Afterglows E p,max ~ EeV PeV-EeV ν, GeV γ

6. Treatment of pγreaction: Rectangular approx.→More sophistication Inclusion of various cooling processes Treatment of the GRB rate history: GRB rate models→ e.g. Guetta et al. (04,07)Outline Prompt (Waxman & Bahcall 97), Afterglow (Waxman & Bahcall 00/Dermer 02) Assumption that observed UHECRs come from GRBs (in original works) Prediction of neutrinos associated with prompt and afterglow emission KM & Nagataki, PRD, 73, 063002 (2006) + Motivated by the recent Swift’s discoveries, we have predicted new possibilities of neutrinos and cosmic rays. KM & Nagataki, PRL, 97, 051101 (2006)KM, Ioka, Nagataki, & Nakamura, ApJL, 651, L5 (2006) Δ-resonance KM, PRD, 76, 123001 (2007) (And many studies, e.g., Halzen & Hooper 99, Guetta et al. 04, Asano 05)

7. Prompt Emission from Classical (High-Luminosity) GRBs Internal Shock Model PeV ν, GeV-TeV γ (Waxman & Bahcall 97) Meszaros (2001) Afterglows External Shock Model EeV ν, GeV-TeV γ (Waxman & Bahcall 00) (Dermer 02)

8. Prompt Neutrino Emission r~10 13 -10 15 cm Inner range (~10 13 cm) neutrino efficient, UHECRs impossible Middle range (~10 14 cm) neutrino efficient, UHE proton possible Outer range (~10 15 cm) neutrino inefficient, UHE nuclei survive large uncertainties... Γ=300, U γ =U B E GRB,γ =10 53 ergs (A&B) A: muon events ~ 0.1 B: muon events ~ 0.01 C: muon events ~ 1 (C is a very extreme case) Only nearby/energetic bursts can be promising (r-determination ← GLAST (e.g., KM & Ioka 08)) A r~10 13.5 cm B r~10 14.5 cm z=1

9. The Cumulative Background ~10 events/yr by IceCube ( fiducial baryon load) Our models are tested by AMANDA/IceCube group. The optimistic model is being constrained (Achterberg et al. 08) fiducial baryon loading E HECR ~ E GRB,γ higher baryon loading E HECR ~ 5 E GRB,γ The key parameter – baryon loading Ε HECR ≡ε 2 N(ε) Set A - r~10 13 -10 14.5 cm Set B - r~10 14 -10 15.5 cm Γ=10 2.5, U γ =U B KM & Nagataki, PRD, 73, 063002 (2006) Current AMANDA limit Towards testing the GRB-UHECR hypothesis through νs

10. Early Afterglows EeV ν, GeV-TeV γ (Dermer 07) (KM 07) Prompt Emission from Low-Luminosity GRBs PeV ν, GeV-TeV γ (KM et al. 06) (Gupta & Zhang 06) Meszaros (2001) Flares PeV-EeV ν, GeV γ (KM &Nagataki 06)

11. Novel Results of Swift (XRF060218) 1. Low-luminosity (LL) GRBs? e.g., GRB060218 (XRF060218) ・ The 2 nd nearby event (~140Mpc) ・ Associated with a SN Ic ・ Thermal component (shock breakout?) ・ Much dimmer than usual GRBs (E LL,γ ~ 10 50 ergs ~ 0.001 E GRB,γ ) ・ LL GRBs (e.g., XRF060218, GRB980425) → more frequent than HL GRBs (Local Rate ~ 10 2-3 Gpc -1 yr -3 ) (Soderberg et al. 06, Liang et al. 07 Guetta et al. 07 etc…) Liang et al. (07) darkbright Rate Luminosity

12. Neutrinos from LL GRBs Ex.) XRF060218-like burst Prompt nonthrmal emission E pk ~ 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/Γ 2 =fixed D=10Mpc Muon events ~ 1 event Muon events ~ 0.1 event See also Gupta & Zhang 07 For early afterglows see Yu, Dai, & Zheng (08)

13. Novel Results of Swift (Flares) 2. Flares in the early afterglow phase Energetic (E flare,γ ~ 0.1 E GRB,γ (Falcone et al. 07) ) (E flare,γ ~ E GRB,γ for some flares such as GRB050502b) δt >~ 10 2-3 s, δt/T < 1 → internal dissipation models (e.g. late internal shock model) Flaring in the (far-UV)/x-ray range (E peak ~ (0.1-1) keV) (Maybe) relatively lower Lorentz factors (Γ ~ a few×10) Flares are common (at least 1/3 ~ 1/2 of LGRBs) (even for SGRBs) Baryonic (possibly dirty fireball?) vs non-baryonic? ↑neutrinos! Flares Burrows et al. (07)

14. Energetics Neutrino Energy Flux ∝ Photopion (p→π) Production Efficiency Nonthermal Baryon Energy ×Rate× HL GRB (Waxman & Bahcall 97) Flare (Murase & Nagataki 06) LL GRB (Murase et al. 06) (Gupta & Zhang 07) Isotropic energy 1~0.01-0.10.001 Pion Production Efficiency 1101 Apparent Rate 11~100-1000 The contribution to neutrino background 1~0.1-1 ↓Normalizing all the typical values for HL GRBs to 1 Hence, we can expect flares and LL GRBs are important!

15. Neutrino Predictions in the Swift Era Possible dominant contribution in the very high energy region KM & Nagataki, PRL, 97, 051101 (2006) KM, Ioka, Nagataki, & Nakamura, ApJL, 651, L5 (2006) Approaches to GRBs through high-energy neutrinos Flares→information on flare models (baryonic or nonbaryonic etc.) LL GRBs→νs as an indicator of far SNe associated with LL GRBs ν flashes → Coincidence with flares/early AGs, a few events/yr νs from LL GRBs → little coincidence with bursts, a few events/yr Flares ( E flare,γ = 0.1 E GRB,γ ) LL GRBs (E LL,γ ~ 0.001 E GRB,γ ) HL GRBs See also, Gupta & Zhang 07

16. Notes on Early Afterglow Emission shallow 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 E shallow,γ ~ 0.1 E GRB,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 loading E HECR ~ E GRB,γ fiducial baryon loading E HECR ~ E shallow,γ ~ 0.1 E GRB,γ steep decay (For forward shock νs, see Dermer 02, 07)

17. Below Photosphere TeV ν (Meszaros & Waxman 01) (Schneider et al. 02) ( Razzaque, Meszaros, & Waxman 03) Meszaros (2001)

18. Below/Around Photosphere pp reaction → based on Geant4 & SYBILL codes Below/around the photosphere (even inside the star) Cosmic-ray acceleration could be still expected (e.g., Meszaros & Waxman 01, Razzaque et al. 03) (pp optical depth) ~ n p σ pp (r/Γ) >~ 0.1 → pp reaction important r=10 12.5 cm Γ=100, U B =0.1U γ strong meson/muon cooling ↓ kaon-contribution is important (Ando & Beacom 05) (Asano & Nagataki 06)

19. Neutrinos and Progenitor Fig. from Razzaque, Meszaros, & Waxman Fabio, KM et al., ApJ (08) termination shock Termination shock → shock dissipation → thermalization ~keV → providing target photons (Meszaros & Waxman 01) (pp neutrinos are not shown→) Schneider et al. (POPIII) Precursor = successful GRBs (GRB rate) Choked = failed GRBs (SN Ibc rate)

20. マスタ サブタイトルの書式設定 20 Connection between Astrophysical Neutrino Sources and High-Energy Cosmic-Rays

21. GRB-UHECR Hypothesis Possible but requiring high baryon loading… (Lower local rate leads to higher baryon load…) The original argument (Waxman 95, Vietri 95) ← UHECR-normalization (except for Flares) Comparable HL Prompt ~ 30 events/yr LL Prompt ~ 10 events/yr AG (ISM) ~ 0.1 events/yr AG (WIND) ~ 1 event/yr Flare ~ 2 events/yr (not UHECR source) KM, PRD, 76, 123001 (07)

22. Notes: HL/LL GRBs and UHECRs UHECR production is possible in low-luminosity GRBs KM, Ioka, Nagataki, & Nakamura, submitted (2008) The source number density ← PAO, TA Burst Models → Sensitive to effective EGMF strength (structured + intergalactic) Necessity of future observations and theoretical studies (see talk by Dr. Takami)

23. Notes: Heavy Nuclei? Wang, Razzaque, & Meszaros (2008) KM, Ioka, Nagataki, & Nakamura, submitted (2008) Γ=10 2.5 Γ=1000 Recent PAO results → (tentative) existence of heavier nuclei (Unger et al. 07) UHE nuclei production in GRBs (IS, RS, and FS models) and hypernovae → Possible at enough large radii r Survival of UHE heavy nuclei → neutrino “dark” → TeV gamma-ray “bright” + secondary delayed emission (Totani 98, Asano & Inoue 07) (KM, Asano, & Nagataki, ApJ (07), Takahashi, KM, et al., in prep. (08)) (talk by Dr. Asano)

24. Neutrinos from AGN The most frequently discussed UHECR candidates (talk by Prof. Blandford, Dr. Inoue) Many theoretical papers on neutrinos (Szabo & Protheroe, Stecker et al., Rachen & Biermann, Muniz & Meszaros, Mannheim, Atoyan & Dermer…) Ex.) Giant AGN Flare model (Farrar & Gruzinov 08) r=10 17.5 cm Γ=10 Muon event rate ~(0.1-1) events/yr

25. Neutrinos from Clusters of Galaxies KM, Inoue & Nagataki, to be submitted (08) KM, Inoue, & Nagataki, in prep. (08) CGs ⇔ The origin of second knee cosmic-rays?? Shock radius ~ virial radius → Muon events ~ a few events/yr Cluster shocks (e.g., accretion shocks) → E max ~ Z 10 19 eV may be possible Diffusion from Central AGN Model (Berezinsky et al., Colafrancesco & Blasi) (See talk by Dr. Inoue) required Broken PL Broken PL spectrum → (0.1-1)% of EGRET limit SN shock + CG shock

26. GZK Neutrinos Ankle model vs dip model → dip model leads to 10 PeV bump Strong evolution model → detection in the near future (Yukusel & Kistler 07) PAO limit Takami, KM, Nagataki, Sato (08) Auger 07 limit E max =10 22 eV CMB+CIB (Best-fit model of Kneiske et al. 04)

27. High-Energy Neutrinos and GRBs: Summary We have performed more sophisticated calculations on neutrino spectra under the internal/external model. Our results have been tested by AMANDA/IceCube. →Our results have been tested by AMANDA/IceCube. We have predicted new possibilities of neutrino emission from GRBs, motivated by Swift observations. Neutrinos from flares and early afterglows 1. Neutrinos from flares and early afterglows Neutrino bursts from low luminosity (LL) GRBs 2. Neutrino bursts from low luminosity (LL) GRBs We can also expect other neutrino signals (CG, AGN etc).We can also expect other neutrino signals (CG, AGN etc). Neutrinos (and gamma-rays) are useful as a probe of cosmic-ray acceleration in astrophysical sources. If detected, we can obtain the important clues to models of the source and cosmic-ray acceleration. The connection between GRBs and UHECRs? High energy neutrino astronomy will come soon!