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

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, 22th-25th April, 2014

Based on arXiv:1403.3020v1 [astro-ph.HE], A&A 564, id.A74

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, 22th-25th April, 2014

Introduction


. Gamma-ray bursts (GRB) - powerful, L1052 erg/s - extragalactic - brief, T~ a fraction to hundreds of seconds - collapse of massive star or merger of 2 stars

Introduction. GRB prompt emission


Light curves

Typical spectrum

Motivation . GRB prompt emission typically, internal shocks

. Synchrotron emissionof accelerated electrons

. Protons co-accelerated imply neutrino emission


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

A two-zone model . For a total GRB event of duration

and observed variability timescale


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)

Some details of the model


escape rate:

acceleration rate:

matter density:magnetic field:

injection point:6x1012 cm for=100

5x1013 cm for =300

4x105 G for=100

2x104 G for =300

Acceleration and cooling rates


Cooling processes:

. adiabatic

. synchrotron

. synchr. self-Compton

. proton-photon

. proton-proton

Electron and proton distributions


Pions and muons. acceleration, cooling and decay rates


efficientmuon acceleration

Pions and muons

. Particle distributions


. pp and ppions (Kelner et al 2006; Atoyan & Dermer 2003)

. decaying muons (Lipari et al 2007)

ResultsMultiWL photon Emission


e-synchrotron responsible for prompt emission

Photon field taken “by hand” in many works

Gamma-ray absorption not included

NeutrinosAcceleration zone:

Cooling zone:

Diffuse neutrino flux:

Effect of flavor oscillation

(Gpc-3 yr-1)

GRB redshift evolution:


Murase & Nagataki (2006)

Neutrinos


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


Thank you!


Extra slides

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, 123005

Murase, K. & Nagataki, S. 2006, Phys. Rev. D 73, 063002

Variability timescale and collision radius

Halzen's Lecture, arXiv:astro-ph/9810368v1

Method of calculation1) solve for N

e in the acceleration zone

2) get the synchrotron emission emitted by the electrons3) solve for N

p in the acceleration zone

4) compute Pion injection (pp and p)5) solve for Nin the acceleration zone6) compute Muon injection7) solve for Nin the acceleration zone

Then compute, for the cooling zone, the injection

of each type of particle: (Ni /t

esc) and solve the

kinetic eq. for each of them.

Monoenergetic injection (e and p)

Normalization constant:

Power injected:

Documents

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