Presentation is loading. Please wait.

Presentation is loading. Please wait.

High-energy photon and particle emission from GRBs/SNe Xiang-Yu Wang Nanjing University, China Co-authors: Zhuo Li (Weizmann), Soebur Razzaque (PennState),

Similar presentations


Presentation on theme: "High-energy photon and particle emission from GRBs/SNe Xiang-Yu Wang Nanjing University, China Co-authors: Zhuo Li (Weizmann), Soebur Razzaque (PennState),"— Presentation transcript:

1 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) 2008 Nanjing GRB conference June 23-27, 2008; Nanjing, China

2 Electrons- Shock acceleration: ~10 TeV Protons (or nuclei)- 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) Particle acceleration in GRB shocks X-ray afterglows modeling e.g. Li & Waxman 2006 Obs. Channel: High-E photons can probe electrons 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 1)Leptonic process: Electron IC 2)Hadronic process GRB GRB940217

5 Leptonic process- inverse Compton scattering 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 Credit P. Meszaros

6 1. IC emission from very early external shocks Shocked shell Shocked ISM Cold ISM Cold shell pressure FS RS CD 1)(rr) 2)(ff) 3)(fr) 4)(rf) Four IC processes (Wang, Dai & Lu 2001 ApJ,556, 1010) At deceleration radius, T_obs~ s Forward shock---Reverse shock structure is developed

7 Energy spectra--- 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 Reverse shock SSC (r,f) IC (f,r) IC Forward shock SSC Log(E/keV) GLAST 5 photons sensitivity (Wang, Dai & Lu 2001 ApJ,556, 1010)

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

9 ~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 2. High-energy photons from X-ray flares Burrows et al Falcone et al amplitude: ~500 times above the underlying afterglow GRB050502B X-ray flares occur inside the deceleration radius of the afterglow shock X-ray flares: late-time central engine activity

10 IC between X-ray flare photons and afterglow electrons (Wang, Li & Meszaros 2006) Cnetral engine X-ray flare photons Forward shock region Cartoon X-ray flare photons illuminate the afterglow shock electrons from inside 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 time and 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 knee ankle GZK cutoff Observed by HiRes and Auger

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) 2nd knee e.g. Berezinsky et al. 06 *

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 GRB )Type Ic SN 2)High peak luminosity, broad emission lines -> modelling require large (E=3-5e52erg) 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/GRB SN2006aj/GRB  prompt thermal x-ray emission—mildly relativistic SN shock breakout from stellar wind Campana et al. 06 Waxman, Meszaros, Campana 07

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 Berezhko & Volk 04 Wang, Soeb, Meszaros, Dai 07

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 Protons can be accelerated to >=1e19 eV Maximum energy: Hillas 84

23 The CR flux level  energetics 1)Extra-galactic hypernova explosion rate 2)average energy per hypernova event Normal Ib/c SN rate: sub-energetic GRB rate: Hypernova (v=0.1c) Normal GRBs Rate (z=0) ~500 ~1 ~1 kinetic energy 3-5e52 erg 1e53-1e54erg Compare with normal GRBs 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 Unger et al. 07, ICRC X_max Possible presence of nuclei in UHECRs

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

26 Speculation on the origin of nuclei 1) GRB internal shock 2) GRB external shock and hypernova models nuclei from swept stellar wind O Fe O C He O C at the base, r=1e6-7cm T=1-10MeV fully photo-disintegrated 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 Constant density medium Wind medium Photon source: Early x-ray afterglow emission

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

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 GRB Neutrinos He/CO star H envelope Buried shocks No  -ray emission Razzaque, Meszaros & Waxman, PRD ‘03 Precursor ’s Internal shocks Prompt  -ray (GRB) Waxman & Bahcall ’97 Murase & Nagataki 07 Burst ’s External shocks Afterglow X,UV,O Waxman & Bahcall ‘00 Afterglow ’s  CR PeV EeV TeV

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) Ryde 05 Rees & Meszaros 05; Pe’er et al. 06

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

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,…


Download ppt "High-energy photon and particle emission from GRBs/SNe Xiang-Yu Wang Nanjing University, China Co-authors: Zhuo Li (Weizmann), Soebur Razzaque (PennState),"

Similar presentations


Ads by Google