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A two-zone model for the production of prompt neutrinos in gamma-ray bursts Matías M. Reynoso IFIMAR-CONICET, Mar del Plata, Argentina GRACO 2, Buenos Aires, 22 th -25 th April, 2014 Based on arXiv: v1 [astro-ph.HE], A&A 564, id.A74

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Plan of the talk. Introduction GRB, spectrum, motivation..... Model description Basic assumptions, physical processes, particle distributions... Results Photon multiwavenlength spectrum, and neutrino flux. Final comments M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014

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Introduction M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, Gamma-ray bursts (GRB) - powerful, L erg/s - extragalactic - brief, T~ a fraction to hundreds of seconds - collapse of massive star or merger of 2 stars

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Introduction. GRB prompt emission M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014 Light curves Typical spectrum

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Motivation. GRB prompt emission typically, internal shocks. Synchrotron emission of accelerated electrons. Protons co-accelerated imply neutrino emission M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014 p or pp Many works (e.g. Waxman & Bahcall 1997; Guetta et al. 2004; Murase & Nagataki 2006; Hümmer et al. 2012; Murase et al. 2012; Baerwald et al. 2012; He et al. 2012) have employed basically “one-zone” models. Acceleration (e.g. by shocks) requires an acceleration zone, not only a radiation zone (Kirk et al. 1998; Protheroe & Stanev 1999) Particle acceleration mechanism can also act on secondary pions and muons

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A two-zone model. For a total GRB event of duration and observed variability timescale M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014 There are a number of injection events Particles are injected and accelerated in the acceleracion zone. The escaping particles are injected in a cooling zone. (Meszaros 2006, Piran 2005, Halzen 1998)

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Some details of the model M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014 escape rate: acceleration rate: matter density: magnetic field: injection point: 6x10 12 cm for =100 5x10 13 cm for =300 4x10 5 G for =100 2x10 4 G for =300 matias.

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Acceleration and cooling rates M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014 Cooling processes:. adiabatic. synchrotron. synchr. self-Compton. proton-photon. proton-proton

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Electron and proton distributions M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014

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Pions and muons. acceleration, cooling and decay rates M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014 efficient muon acceleration

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Pions and muons. Particle distributions M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, pp and p pions (Kelner et al 2006; Atoyan & Dermer 2003). decaying muons (Lipari et al 2007)

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Results MultiWL photon Emission M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014 e-synchrotron responsible for prompt emission Photon field taken “by hand” in many works Gamma-ray absorption not included

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Neutrinos Acceleration zone: Cooling zone: Diffuse neutrino flux: Effect of flavor oscillation (Gpc -3 yr -1 ) GRB redshift evolution: M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014 Murase & Nagataki (2006)

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Neutrinos M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014

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Final comments.) Particle acceleration: included in a simple two-zone model for GRB.) Secondary particles produced in the acceleration zone can get accelerated.) If the escape rate of particles in the acceleration zone is lower than the rate of acceleration, then electrons in the acceleration zone produce synchrotron radiation that can be consistent with the prompt emission..) Neutrinos are produced in both zones by p and pp interactions. The diffuse flux can account for the recent neutrino data obtained by IceCube. Future work: - Include convection term in kinetic equation - Study an especific acceleration mechanism - Include Fermi II acceleration - Apply to other magnetized sources M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014

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Thank you! M.M. Reynoso - GRACO 2, Buenos Aires, 22 th -25 th April, 2014

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Extra slides

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Useful references Protheroe, R. J. & Stanev, T. 1999, Astropart. Phys. 1O, 185 Mészáros, P. 2006, Rept. Prog. Phys. 69, 2259 Kirk, J. G., Rieger, F. M., Mastichiadis, A. 1998, A&A 333, 452 Waxman, E. & Bahcall, J. 1997, Phys. Rev. Lett. 78, 2292 Lipari, P., Lusignoli, M., & Meloni, D. 2007, Phys. Rev. D 75, Murase, K. & Nagataki, S. 2006, Phys. Rev. D 73,

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Variability timescale and collision radius Halzen's Lecture, arXiv:astro-ph/ v1

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Method of calculation 1) solve for N e in the acceleration zone 2) get the synchrotron emission emitted by the electrons 3) solve for N p in the acceleration zone 4) compute Pion injection (pp and p ) 5) solve for N in the acceleration zone 6) compute Muon injection 7) solve for N in the acceleration zone Then compute, for the cooling zone, the injection of each type of particle: (N i / t esc ) and solve the kinetic eq. for each of them. Monoenergetic injection (e and p) Normalization constant: Power injected:

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