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High-energy photon and particle emission from GRBs/SNe

2008 Nanjing GRB conference June 23-27, 2008; Nanjing, China. High-energy photon and particle emission from GRBs/SNe. Xiang-Yu Wang Nanjing University, China Co-authors: Zhuo Li (Weizmann), Soebur Razzaque (PennState), Peter Meszaros (PennState), Zi-Gao Dai (NJU).

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High-energy photon and particle emission from GRBs/SNe

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  1. 2008 Nanjing GRB conference June 23-27, 2008; Nanjing, China High-energy photon and particle emission from GRBs/SNe Xiang-Yu Wang Nanjing University, China Co-authors: Zhuo Li (Weizmann), Soebur Razzaque (PennState), Peter Meszaros (PennState), Zi-Gao Dai (NJU)

  2. Particle acceleration in GRB shocks • Electrons- Shock acceleration: ~10 TeV • Protons (or nuclei)- X-ray afterglows modeling e.g. Li & Waxman 2006 Obs. Channel: High-E photons can probe electrons 1) Shock acceleration(e.g. Waxman 1995; Vietri 1995) Candidate source of ultra-high energy cosmic rays (UHECRs) 2) Neutrinos from photo-meson and pp processes (e.g. Waxman & Bahcall 1997; Bottcher & Dermer 1998) Obs. Channel: High-energy particles (UHECRS, Neutrinos)

  3. Outline • High-energy gamma-ray emission from GRBs • GRB/Hypernova model for UHECRs • UHE nuclei: acceleration and survival in the sources • Prompt TeV neutrino emission from sub-photosphere shocks of GRBs

  4. I. High-energy gamma-rays • Two basic mechanisms • Leptonic process: Electron IC • Hadronic process GRB930131 GRB940217

  5. Leptonic process- inverse Compton scattering Credit P. Meszaros Internal shock IC:e.g. Pilla & Loeb 1998; Razzaque et al. 2004; Gupta & Zhang 2007 External shock IC reverse shock IC: e.g. Meszaros , et al. 94; Wang et al. 01; Granot & Guetta 03 forward shock IC: e.g.Meszaros & Rees 94; Dermer et al. 00; Zhang & Meszaros 01

  6. 1. IC emission from veryearly external shocks (Wang, Dai & Lu 2001 ApJ,556, 1010) At deceleration radius, T_obs~10-100 s Forward shock---Reverse shock structure is developed CD pressure Shocked shell Shocked ISM Four IC processes RS FS • (rr) • (ff) • (fr) • (rf) Cold shell Cold ISM

  7. Energy spectra--- (Wang, Dai & Lu 2001 ApJ,556, 1010) GLAST 5 photons sensitivity (r,f) IC Reverse shock SSC Forward shock SSC (f,r) IC Log(E/keV) At sub-GeV to GeV energies, the SSC of reverse shock is dominant; at higher energies, the Combined IC or SSC of forward shock becomes increasingly dominated

  8. One GeV burst with very hard spectrum- leptonic or hadronic process? GRB941017 −18 s – 14 s 14 s – 47 s Reverse shock SSC ISM medium environment 47 s – 80 s 80 s – 113 s Wang X Y et al. 05, A&A, 439,957 113 s – 211 s Leptonic IC model: Granot & Guetta 03 Pe’er & Waxman 04 Wang X Y et al. 05 Gonzalez et al. 03: Hadronic model

  9. 2. High-energy photons from X-ray flares X-ray flares: late-time central engine activity • ~30%-50% early afterglow have x-ray flares, Swift discovery • Flare light curves: rapid rise and decay <<1 • Afterglow decay consistent with a single power-law before and after the flare amplitude: ~500 times above the underlying afterglow GRB050502B X-ray flares occur inside the deceleration radius of the afterglow shock Burrows et al. 2005 Falcone et al. 2006

  10. IC between X-ray flare photons and afterglow electrons (Wang, Li & Meszaros 2006) X-ray flare photons illuminate the afterglow shock electrons from inside Cartoon Cnetral engine X-ray flare photons Forward shock region also see Fan & Piran 2006: unseen UV photons

  11. IC GeV flare fluence-An estimate • So most energy of the newly shock electrons will be lost into IC emission X-ray flare peak energy

  12. Temporal behavior of the IC emission • Not exactly correlated with the X-ray flare light curves. IC emission will be lengthened by the afterglow shock angular spreading timeand the anisotropic IC effect Self-IC of flares, peak at lower energies Wang, Li & Meszaros 2006 In external shock model for x-ray flares

  13. What could GLAST tell us? • Origin of GeV photons (both prompt and delayed): spectral and temporal properties • Magnetic field in the shocks: • Maximum energy of the shock accelerated electrons : • … Launched 11/06/2008

  14. high-E protons or nuclei in GRB shocks? • Hypernova model for UHECRs • High-energy nuclei in UHECRs • Neutrinos-

  15. CR spectrum -2.7 -3.1 knee GZK cutoff Observed by HiRes and Auger ankle

  16. Galactic CR--Extra-galactic CR transition • CRs below the knee: protons accelerated by Galactic SNR • Galactic CRs may extent up to >1e17eV: high-z nuclei • Transition position from GCR to EGCR: still controversial 1) ankle: EGCRs start at E>1e19 eV require GCRs extending to ~1e19 eV (e.g. Budnik et al. 07) 2) the second knee: E~6e17 eV where the composition changes significantly (HiRes data) * e.g. Berezinsky et al. 06 2nd knee

  17. Source models for EGCRs • AGNs, radio galaxies (Biermann….) • GRBs (waxman 05; Vietri; Dermer) • Cluster of galaxies • Magnetar (Ghisellini’s talk) • … • Semi-relativistic Hypernovae: ? large explosion energy SN (E=3-5e52erg) with significant mildly-relativistic ejecta 3C 296 GRB Wang et al.2007

  18. Hypernova prototype – SN1998bw: an unusual SN In the error box of GRB980425 • Type Ic SN • High peak luminosity, broad emission lines -> modelling require large • explosion energy (E=3-5e52erg) Normal SN: E=1e51 erg

  19. GRB980425: gamma-ray, radio & x-ray observations • sub-energetic GRB—GRB980425: E~1e48 erg (d=38 Mpc) • Radio afterglow modeling: E>1e49 erg, \Gamma~1-2 • X-ray afterglow: E~5e49 erg, \beta=0.8 (Waxman 2004) Mildly relativistic ejecta component

  20. Other hypernovae/sub-energetic GRBs • SN2003lw/GRB031203 • SN2006aj/GRB060218 • prompt thermal x-ray emission—mildly relativistic SN shock breakout from stellar wind Waxman, Meszaros, Campana 07 Campana et al. 06

  21. CR spectrum — Hypernova energy distribution with velocity • Semi-relativistic hypernova: high velocity ejecta with significant energy is essential • Normal SN Very steep distribution -> negligible contribution to high-energy CRs Wang, Soeb, Meszaros, Dai 07 Berezhko & Volk 04

  22. The maximum energy of accelerated particles 1) Type Ib/c SN expanding into the stellar wind, Wolf-Rayet star 2) equipartition magnetic field B, both upstream and downstream Maximum energy: Hillas 84 Protons can be accelerated to >=1e19 eV

  23. The CR flux level  energetics • Extra-galactic hypernova explosion rate • average energy per hypernova event Compare with normal GRBs Normal Ib/c SN rate: sub-energetic GRB rate: The required rate : Soderberg et al. 06; Liang et al. 06

  24. UHECR chemical composition--Auger result Elongation Rate measured over two decades of energy X_max Unger et al. 07, ICRC Possible presence of nuclei in UHECRs

  25. Origin and survival of UHE nuclei Wang, Razzaque & Meszaros 08 • GRB Internal shock (Waxman 1995) External shock (Vietri 95, Dermer et al. 01) • Hypernova remnant: mildly-relativistic ejecta Central engine Internal shock Relativistic outflow External shock

  26. Speculation on the origin of nuclei • 1) GRB internal shock • 2) GRB external shock and hypernova models nuclei from swept stellar wind at the base, r=1e6-7cm T=1-10MeV fully photo-disintegrated O He O C C O Fe Mixing of surrounding material into the jet

  27. Survival of UHE nuclei photo-disintegration or photopion energy loss rate: Condition for survival:

  28. Survival of UHE nuclei–internal shock

  29. Survival of UHE nuclei– External shock Optical depth for photo-disintegration Maximum particle energy Photon source: Early x-ray afterglow emission Constant density medium Wind medium

  30. Survival of UHE nuclei – Hypernova remnants Optical depth for photo-disintegration Maximum particle energy

  31. Survival of UHE nuclei Conclusions: survival of heavy nuclei in the following sources • GRB internal shock – give constraints • GRB external shock -ok • Hypernova remnant -ok

  32. Buried shocks No -ray emission Precursor ’s Razzaque, Meszaros & Waxman, PRD ‘03 GRB Neutrinos H envelope He/CO star CR      External shocks Afterglow X,UV,O Internal shocks Prompt -ray (GRB) TeV Afterglow ’s Burst ’s PeV Waxman & Bahcall ‘00 Waxman & Bahcall ’97 Murase & Nagataki07 EeV

  33. Neutrino emission during the prompt phase • Waxman & Bahcall (1997), Dermer & Atoyan 03 Murase &Nagataki 06 • Broken power-law spectrum for radiation photons

  34. photosphere component in the prompt emission • Motivation: prompt thermal emission • Advantages of Thermal component: The “death line” problem; clustering of peak energies; Amati relation • Hybrid model: thermal (sub-photosphere) + non-thermal (further out, optically thin shocks) • Origin of thermal emission: sub-photosphere internal shocks (Rees & Meszaros 05) Rees & Meszaros 05; Pe’er et al. 06 Ryde 05

  35. Prompt neutrinos associated with dissipative photosphere Wang & Dai 08 Inverse cooling time for protons Diffuse neutrino spectrum

  36. Promising prospect for GRB high-energy process : Multi-messenger observation era • Photons– GLAST, HESS, HAWC… • Neutrinos--Icecube, KM^3, ANITA… • Cosmic Rays--Pierre Auger South, North,… 2008 2011 2007-

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