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High Energy Radiation from Black Holes in GRBs

High Energy Radiation from Black Holes in GRBs. Chuck Dermer Naval Research Laboratory charles.dermer@nrl.navy.mil Govind Menon (Troy) Soebur Razzaque (NRL) Justin Finke (NRL) Armen Atoyan (Concordia). 1. High Energy Radiation from GRBs Results from Fermi Hadronic origin?

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High Energy Radiation from Black Holes in GRBs

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  1. High Energy Radiation from Black Holes in GRBs Chuck Dermer Naval Research Laboratory charles.dermer@nrl.navy.mil Govind Menon (Troy) Soebur Razzaque (NRL) Justin Finke (NRL) Armen Atoyan (Concordia) 1. High Energy Radiation from GRBs Results from Fermi Hadronic origin? 2. UHECRs from GRBs 3. UHE neutrinos from GRBs (Princeton U. Press, 2009) Dermer 2010 APS Meeting, Washington, DC 14 February 2010

  2. Cenko et al. 2009 Properties of Fermi LAT GRBs 090902B 090923A 090510A 080916C Large apparent isotropic energy releases ( small jet angles) Delayed onset of GeV emission Extended GeV radiation Hard power-law component in addition to Band component Large values of Gmin

  3. Properties of Fermi LAT GRBs (short) GRB 090510 8 - 260 keV Large apparent isotropic energy releases ( small jet angles) Delayed onset of GeV emission Extended GeV radiation Hard power-law component in addition to Band component Large values of Gmin 260 keV – 5 MeV all LAT events >100 MeV > 1 GeV -0.5 0 0.5 1 1.5 2 2.5 3 t(s)

  4. Properties of Fermi LAT GRBs (long) GRB 090902B 8 – 14.3 keV Large apparent isotropic energy releases ( small jet angles) Delayed onset of keV/GeV emission Extended GeV radiation Hard power-law component in addition to Band component Large values of Gmin 14.3 – 260 keV 260 keV – 5 MeV LAT (all events) > 100 MeV > 1 GeV 0 20 40 60 80 t(s)

  5. GRB 090902B Properties of Fermi LAT GRBs Large apparent isotropic energy releases ( small jet angles) Delayed onset of GeV emission Extended GeV radiation Hard power-law component in addition to Band component Large values of Gmin GRB 090510 Also, at <3s significance, in GRB 080916C

  6. Properties of Fermi LAT GRBs Large apparent isotropic energy releases ( small jet angles) Delayed onset of GeV emission Extended GeV radiation Hard power-law component in addition to Band component Large values of Gmin R′cGtvar Gmin  900, GRB 080916C 1000, GRB 090902B 1200, GRB 090510

  7. Particle Acceleration to Ultra-High Energies by GRBs by Fermi processes Proper frame (´) energy density of relativistic wind with apparent luminosity L Maximum particle energy x G Lorentz contraction: GRB energetics favorable for UHECR proton production GRBs have typical (apparent isotropic) Lg > 1051 erg s-1  L > Lg L>> 1051 erg s-1 Dermer 2010 APS Meeting, Washington, DC 14 February 2010

  8. Proton Synchrotron Model for GeV Radiation in GRBs Accumulation and cooling of protons makes delayed proton synchrotron g radiation ggprocesses induce second-generation electron synchrotron spectrum Energetics difficulties (requires ~100 – 1000 more energy in magnetic field and protons than observed in g rays) Zhang & Mészáros (2001) Wang, Li, Dai, Mészáros (2009) Razzaque, CD,Finke, arXiv:0908.0513 Only plausible for 1. small jet opening angle 2. G < Gmin • nFn • (erg cm-2 s-1) Dermer 2010 APS Meeting, Washington, DC 14 February 2010

  9. Asano, Guiriec, Mészáros (2009) for GRB 090510 Photohadronic Model for GeV Radiation in GRBs Hard g-ray emission component fromhadronic-induced electromagnetic cascade radiationinside GRB blast wave Second component from outflowing high-energy neutral beam of neutrons, g-rays, and neutrinos Also requires large energies Baryon Loading fb = 1 Ftot = 310-4 erg cm-2 G = 100 CD & Atoyan 2006 Dermer 2010 APS Meeting, Washington, DC 14 February 2010

  10. UHECR Emissivity knee ankle (Waxman 1995, Vietri 1995) Sources of (>1018 eV) UHECRs need to have local luminosity density of >1044 erg/(Mpc3-yr) Dermer 2010 APS Meeting, Washington, DC 14 February 2010

  11. Luminosity Density of GRBs Time-averaged GRB energy flux: > 20 keV fluence distribution of 1,973 BATSE GRBs (477 short GRBs and 1,496 long GRBs). 670 BATSE GRBs/yr (full sky) (independent of beaming) SFR, GRB types, baryon loading? (Band 2001) Dermer 2010 APS Meeting, Washington, DC 14 February 2010

  12. UHECR Spectrum from Long-Duration GRBs • Inject -2.2 spectrum of UHECR protons to E > 1020 eV • Injection rate density determined by birth rate of GRBs early in the history of the universe • GZK cutoff from photopion interactions with cosmic microwave radiation photons • Ankle formed by photo-pair processes (Berezinskii, et al.) Wick, CD, and Atoyan 2004 Hopkins & Beacom 2006 Requires large baryon load ~ 50 Dermer 2010 APS Meeting, Washington, DC 14 February 2010

  13. Hadronic GRB Modeling Baryon Loading Factor fb = 20 Energy injected in protons normalized to GRB MeV fluence F = 3×10-5 erg cm-2 G Injected proton distribution in 50 one-second pulses • UHE neutral • beam: • neutrons • g rays • neutrinos Escaping neutron distribution Cooled proton distribution Dermer 2010 APS Meeting, Washington, DC 14 February 2010

  14. Neutrinos from GRBs in the Collapsar Model Baryon Loading Factor fb = 20 For a fluence of 3×10-4 erg cm-2 (~2 GRBs per year) Nn predicted for IceCube: Nn  1.3, 0.1, 0.016 for G = 100, 200, 300 (fb = 20 for G = 100, limited by requirement that cascade g-ray fluence less than MeV fluence) G G G Dermer & Atoyan 2006 Dermer 2010 APS Meeting, Washington, DC 14 February 2010

  15. Requirements on IGM Field from GRB Space Density • Long GRB rate 2fb Gpc-3 yr-1 at the redshift z  1–2 • 10 smaller at 100d100 Mpc due to the star formation • fb > 200 larger due to a beaming factor • 60E60 EeV UHECR deflected by an angle • in IGM field with mean strength BnGnG coherence length of l1 Mpc • Number of GRB sources within 100 Mpc with jets pointing within 4 of our line-of-sight is • For “strong” ~nG IGM fields and narrow jets accelerating UHECR protons, then long duration GRBs could be sources of UHECRs. Dermer 2010 APS Meeting, Washington, DC 14 February 2010

  16. Highest Energy Radiations from GRBs Centaurus A 1. Hadronic origin of g-rays inconclusive 2. Fermi results imply large energy requirements for hadronic model 3. Large G factors not favorable for neutral beam production 4. Evidence from Auger (not HiRes!) for UHECR ions also makes GRB origin problematic Conclusion: AGN/radio galaxy origin of UHECRs favored (see CD, Razzaque, Finke, Atoyan, NJP 2009) Dermer 2010 APS Meeting, Washington, DC 14 February 2010

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