1 / 15

Microscopic Processes on Radiation from accelerated Particles in Relativistic Jets

Ken Nishikawa National Space Science & Technology Center/UAH Collaborators: M. Medvedev ( Univ. of Kansas ) B. Zhang ( Univ. Nevada, Las Vegas ) P. Hardee ( Univ. of Alabama, Tuscaloosa ) J. Niemiec ( Institute of Nuclear Physics PAN )

tania
Download Presentation

Microscopic Processes on Radiation from accelerated Particles in Relativistic Jets

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ken Nishikawa National Space Science & Technology Center/UAH Collaborators: M. Medvedev (Univ. of Kansas) B. Zhang (Univ. Nevada, Las Vegas) P. Hardee (Univ. of Alabama, Tuscaloosa) J. Niemiec (Institute of Nuclear Physics PAN) Y. Mizuno (Univ. Alabama in Huntsville/CSPAR) Å. Nordlund (Neils Bohr Institute) J. Frederiksen (Neils Bohr Institute) H. Sol (Meudon Observatory) M. Pohl (Iowa State University) D. H. Hartmann (Clemson Univ.) M. Oka (UAH/CSPAR) G. J. Fishman (NASA/MSFC ) Microscopic Processes on Radiation from accelerated Particles in Relativistic Jets Frontiers of Space Astrophysics: Neutron Stars & Gamma Ray Bursts Cairo & Alexandria, March 30 - April 4, 2009

  2. Present theory of Synchrotron radiation • Fermi acceleration (Monte Carlo simulations are not self-consistent; particles are crossing at the shock surface many times and accelerated, the strength of turbulent magnetic fields are assumed), New simulations show Fermi acceleration (Spitkovsky 2008, Martins et al. 2009) • The strength of magnetic fields is assumed based on the equipartition (magnetic field is similar to the thermal energy) (B) • The density of accelerated electrons are assumed by the power law (F() = p; p = 2.2?) (e) • Synchrotron emission is calculated based on p and B • There are many assumptions in this calculation

  3. Radiation from collisionless shock New approach: Calculate radiation from integrating position, velocity, and acceleration of ensemble of particles (electrons and positrons) Hededal, Thesis 2005 (astro-ph/0506559)Nishikawa et al. 2008 (astro-ph/0802.2558)

  4. Synchrotron radiation from gyrating electrons in a uniform magnetic field electron trajectories radiation electric field observed at long distance  B  β β n observer  β β n spectra with different viewing angles time evolution of three frequencies 0° 4° 3° 2° 1° 6° 5° f/ωpe = 8.5, 74.8, 654. theoretical synchrotron spectrum

  5. Cyclotron radiation γ = 15 Angle dependence of radiation (74.4) Radiation ratio at θ = 0 and π/2 from Landau & Lifshitz, The Classical Theory of Fields, 1980

  6. Synchrotron radiation from propagating electrons in a uniform magnetic field electron trajectories radiation electric field observed at long distance B θ observer spectra with different viewing angles θΓ = 4.25° gyrating Nishikawa et al. astro-ph/0809.5067

  7. (Nishikawa et al. astro-ph/0809.5067)

  8. injected at z = 25Δ 3-D simulation Y jet with MPI code Weibel inst Z Weibel inst X 131×131×4005 grids (not scaled) 1.2 billion particles jet front ambient plasma

  9. Phase space of electrons red: jet electrons, blue: ambient electrons Phase space of electrons in the x/∆−γvx at t = 3250ωpe-1. Red dots show jet electrons which are injected from the left with γvx =15 (Nishikawa et al. ApJL, submitted, 2009, arXiv:0904.0096)

  10. Shock velocity and bulk velocity contact discontinuity trailing shock (reverse shock) leading shock (forward shock) jet electrons Fermi acceleration ? total electrons ambient electrons

  11. Shock formation, forward shock, reverse shock vts=0.56c vcd=0.76c total ambient vjf=0.996c jet εB εE • electron density and (b) electromagnetic • field energy (εB, εE) divided by the total • kinetic energy at t = 3250ωpe-1 Time evolution of the total electron density. The velocity of jet front is nearly c, the predicted contact discontinuity speed is 0.76c, and the velocity of trailing shock is 0.56c. (Nishikawa et al. ApJL, submitted, 2009 arXiv:0904.0096)

  12. Radiation from collisionless shock ☺ observer Power Shock simulations GRB Hededal Thesis: Hededal & Nordlund 2005, submitted to ApJL (astro-ph/0511662)

  13. Summary of new simulation • Due to the acceleration of the ambient plasma (electrons • and positrons) a shock is formed at the same time a reverse • shock is created. • The velocities of shock-like structure are characterized by • the shock theory. • The preliminary simulation with an electron-ion jet injected • into an electron-ion ambient plasma show very slow • formation of shock-like structure as expected. • Further simulations with a large system with various • parameters are necessary to investigate a shock formation

  14. Gamma-Ray Large Area Space Telescope (GLAST)(launched on June 11, 2008)http://www-glast.stanford.edu/ Compton Gamma-Ray Observatory (CGRO) Burst And Transient Source Experiment (BATSE) (1991-2000) PI: Jerry Fishman • Large Area Telescope (LAT) PI: Peter Michaelson:gamma-ray energies between 20 MeV to about 300 GeV • GLAST Burst Monitor (GBM) PI: Chip Meegan (MSFC): X-rays and gamma rays with energies between 8 keV and 25 MeV(http://gammaray.nsstc.nasa.gov/gbm/) The combination of the GBM and the LAT provides a powerful tool for studying radiation from relativistic jets and gamma-ray bursts, particularly for time-resolved spectral studies over very large energy band. Fermi (GLAST) All sky monitor

  15. GRB progenitor relativistic jet Fushin (god of wind) (Tanyu Kano 1657) emission (shocks, acceleration) Raishin (god of lightning)

More Related