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Gamma-Ray Bursts & High Energy Astrophysics

Gamma-Ray Bursts & High Energy Astrophysics. Kunihito Ioka (KEK) 井岡 邦仁. Universe. g/cm 3. 10 20. Quark Nucleon. Neutron star. Quantum mechanics D x D p ≥ ℏ General relativity R BH =2GM/c 2 Various scales ⇒ Order estimate. 10 10. White dwarf. Atom. Sun. 10 0.

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Gamma-Ray Bursts & High Energy Astrophysics

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  1. Gamma-Ray Bursts &High Energy Astrophysics Kunihito Ioka (KEK) 井岡 邦仁

  2. Universe g/cm3 1020 Quark Nucleon Neutron star Quantum mechanics DxDp ≥ℏ General relativity RBH=2GM/c2 Various scales ⇒ Order estimate 1010 White dwarf Atom Sun 100 Black hole limit r=c2/2GL2 Human Ultimate goal of Astrophysics is to reveal all cosmic phenomena based on physics 10-10 Solar system r=ћ/cL4 Uncertainty limit Galaxy 10-20 Cluster Universe 10-30 10-10 100 1010 1030 1020 cm

  3. Cosmic jet Man-made accelerator AGN(Active Galactic Nuclei) ~106-9M☉BH Microquasar Current Pulsar ~10M☉BH GRB Energy Neutron star L~1051erg/s~1044W »106W (man-made) Big Puzzle BH formation?

  4. Cosmic ray LHC Flux High energy particles (proton, heavy nuclei) pervade the universe Origin is unknown Up to ~1020eV » 1013eV (man-made) If1g matter turns into 1020eV cosmic ray, we can supply our electric power for 105yr! Cosmic ray spectrum 1 particle/km2/century GeV 1020eV Bhattacharjee&Sigl00

  5. GRB E=mc2 (by Einstein) = = GRB ~1052erg Sun ~1033g Atomic bomb ~1kg In ~sec, GRB release energy Sun emit over lifetime GRBis the most luminous object

  6. Astronomical observation Too small size Light curve Spectrum Sky position Photon (g) Observation+Physics ⇒ We understand cosmic phenomena Multi-wavelength: Optical (eV) +Radio (meV), Microwave (meV), Infrared (eV), X-ray (keV), g-ray (MeV)

  7. GRB observation The most luminous ~1051 erg/s Luminosity Cosmological distance >msec Afterglow GRB X Opt Radio Redshift ~1000 events/yr Isotropic sky distribution ~200 keV, nonthermal 10-3s~103s : Short, Long Supernova Distance unknown ⇒ True energy unknown ~1day Time ~10sec

  8. Paradox? msecx c~ 300km MeVg-ray number density> 1029cm-3 1051erg/s x msec ~ 1048erg Interaction length ~(10-25x1029)-1cm ~10-4cm < 300km e- e+ g g g-ray can not escape?

  9. 99.99% of light speed Unique solution Lorentz factor

  10. Blue-shift 1MeV 10keV MeV=106eV keV=103eV mec2~MeV Comoving frame Observer frame G~100 Similar to the Dopplar effect for a crossing silen Low energy g can not produce e±

  11. Standard model Internal shock Massive star SN ? Inter stellar medium v>99.99%c External shock Central Engine 光度 Afterglow Kinetic energy ↓ Shock dissipation GRB 時間

  12. GRB ≈ BH formation GRBjet breaks out of massive stellar envelope msec x c ~ 300km ~ BH radius ? Why BH launches relativistic jet?

  13. Multi-messenger Too small size Light curve Spectrum Sky position Photon (g) + Other particles Photon (meV-MeV) + High energyg(MeV-100TeV) Cosmic ray (GeV-1020eV) Neutrino (MeV-1019eV) Gravitational wave (nHz-kHz)

  14. Fermi has launched! 11 Jun 2008, GLAST→Fermi GBM: 0.01-30MeV, 8sr, 1ores LAT: 0.02-300GeV, 2.5sr, 5o-5’res LAT first all-sky map Only 4day data = 1 yr data by previous mission

  15. GBMFirst GRBs 31 GRBs per 1st month (⇒ 372/yr) Slightly more than predicted Within a few degrees of Swift calculations

  16. Blue-shift 1MeV 10keV MeV=106eV keV=103eV mec2~MeV Comoving frame Observer frame G~100 Similar to the Dopplar effect for a crossing silen Low energy g can not produce e±

  17. Blue-shift 1GeV 10MeV MeV=106eV keV=103eV mec2~MeV Comoving frame Observer frame G~100 High energy gcan produce e± ⇒ gflux is suppressed

  18. e±cutoff and line 1. e±cutoff energy ⇒ Jet velocity 2. e± line ⇒ e± abundance (⇒ Jet properties ⇒ Central engine) Luminosity KI+ 07 Murase&KI 08 Photon spectrum energy

  19. High energy proton Jet likely contains (proton, heavy nuclei) + (g, e±) Proton interacts with g more weakly than g Pion (p) mass > e mass ⇒ Higher energy cutoff Luminosity cutoff cutoff Photon spectrum Proton spectrum Energy ~GeV (109eV) >1020eV

  20. Cosmic ray from GRB GRB could be the origin of 1020eV cosmic ray! GRB energy generation rate ~ CR energy generation rate Cosmic ray composition ⇒ Jet composition (p, Fe?) ⇒ Central engine 1 particle/km2/century Bhattacharjee&Sigl00

  21. High energy neutrino proton nm ne n ⇒ High energy n (~5% x eproton) g m+ p+ e+ ⇒ Proton fraction ⇒ Central engine Strong penetration Not delayed CR origin n interaction@>TeV t appearance Limittingn speed Equivalence principle Neutrino spectrum Murase,KI+(06)

  22. IceCube @South pole On-going Completion by 2011 V~km3

  23. Gravitational wave GW can directly “see” the central engine Short GRB: origin unknown Long GRB Transparent for GW Charge motion ⇒ Photon Mass motion ⇒ GW(v=c) (ripple of the space-time) Waveform ⇔ Mass, Radius, … Amplitude Time

  24. Direct detection Laser interferometers TAMA LIGO VIRGO GEO GW ~km GR test: Novel prize Short GRB origin Nuclear physics Dx/x~GM/r~10-22 Free mass separation changes

  25. Summary GRB: Most luminous object Multi-wavelength obs. ⇒ Massive star, Relativistic jet, BH/NS Multi-messenger obs. High energy g Cosmic Ray Neutrino Gravitational wave ⇒ Central engine (BH formation), Jet, … High Energy Astrophysics Unexpected may be waiting

  26. Livingston plot ? Planck scale in ~190 yr Center-of-Mass Energy Man-made accelerator is already saturating (top) (W±,Z) (Nn=3) (gluon) Cosmic accelerator could expand the energy frontier (J/y, t) Year

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