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Sources of GeV Photons and the Fermi Results

Chuck Dermer, NRL. Sources of GeV Photons and the Fermi Results. charles.dermer@nrl.navy.mil. 1. GeV instrumentation and the GeV sky with the Fermi Gamma-ray Space Telescope 2. First Fermi Catalog of Gamma Ray Sources and the Fermi Pulsar Catalog 3. First Fermi AGN Catalog

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Sources of GeV Photons and the Fermi Results

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  1. Chuck Dermer, NRL Sources of GeV Photons and the Fermi Results charles.dermer@nrl.navy.mil 1. GeV instrumentation and the GeV sky with the Fermi Gamma-ray Space Telescope 2. First Fermi Catalog of Gamma Ray Sources and the Fermi Pulsar Catalog 3.First Fermi AGN Catalog 4. Relativistic jet physics and blazars 5. g rays from cosmic rays in the Galaxy 6. g rays from star-forming galaxies and clusters of galaxies, and the diffuse extragalactic g-ray background 7. Microquasars, radio galaxies, and the extragalactic background light 8. Fermi Observations of Gamma Ray Bursts 9. Fermi acceleration, ultra-high energy cosmic rays, and Fermi Dermer Saas-Fee Lecture 9 15-20 March 2010

  2. The train is moving Fermi LAT Detection of a New Galactic Plane Gamma-ray Transient in the Cygnus Region: Fermi J2102+4542, and its Possible Association with V407 Cyg ATel #2487; C.C. Cheung (NRC/NRL), D. Donato (NASA GSFC), E. Wallace (U. Washington), R. Corbet (NASA GSFC), G. Dubus (U. Grenoble), K. Sokolovsky (MPIfR), H. Takahashi (Hiroshima U.); on behalf of the Fermi Large Area Telescope Collaboration on 18 Mar 2010; 16:52 UTSubjects: Gamma Ray, >GeV, Transients The Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope, has detected a transient gamma-ray source in the Galactic Plane: Fermi J2102+4542. Preliminary analysis of the Fermi-LAT data indicates that on the 13th and 14th of March 2010, the source was detected with a >100 MeV flux of (1.0 +/- 0.3) x 10^-6 ph cm^-2 s^-1 and (1.4 +/- 0.4) x 10^-6 ph cm^-2 s^-1, respectively (statistical only) -- corresponding significances on these days are 8 sigma and 6 sigma. A systematic uncertainty of 30% should be added to this number. There is no previously reported gamma-ray source at this location. Combining data for the period from Mar 12 0:0:0 UTC and ending Mar 16 ~8:30 UTC, the preliminary LAT position is (J2000.0): RA = 315.60 deg., Dec = 45.71 deg. (l, b = 86.96 deg, -0.55 deg) which is in the Cygnus region of our Galaxy. There is no previously reported EGRET or LAT gamma-ray source at this position. Within the 95% confidence error circle radius of 0.12 deg (statistical only) is the symbiotic star V407 Cyg, with a reported optical outburst beginning approximately 2 days earlier (CBET # 2199 ) than the onset of gamma-ray activity detected by the LAT. Swift/XRT observations triggered on the optical outburst of V407 Cyg and performed on March 13th and 15th resulted in 2.4-2.6 sigma (0.3-10 keV) detections of an X-ray source coincident with the position of the star in each of the two 960 sec exposures. Dermer Saas-Fee Lecture 9 15-20 March 2010

  3. Fermi Acceleration, Ultra-High Energy Cosmic Rays, and Fermi Results Can Fermi data help answer the question of the origin of the Ultra-High Energy Cosmic Rays? Chuck Dermer (NRL) Fermi acceleration and the Crab nebula • GZK Effect • Hillas Criterion • L-G Diagram Dermer Saas-Fee Lecture 9 15-20 March 2010

  4. Abdo, A. A., et al. 2010, ApJ, 708, 1254 Counts maps (arbitrary units) presenting the pulsed (top row) and nebular (bottom row) emission, in three energy bands. Each panel spans 15◦ × 15◦ in equatorial coordinates and is centered on the pulsar radio position. Left: 100 MeV < E < 300 MeV; middle: 300 MeV < E < 1 GeV; right: E >1 GeV. Crab Nebula (M1) with HST Crab Pulsar and Nebula Dermer Saas-Fee Lecture 9 15-20 March 2010

  5. Crab Nebular Spectrum Counts maps (arbitrary units) presenting the pulsed (top row) and nebular (bottom row) emission, in three energy bands. Each panel spans 15◦ × 15◦ in equatorial coordinates and is centered on the pulsar radio position. Left: 100 MeV < E < 300 MeV; middle: 300 MeV < E < 1 GeV; right: E >1 GeV. Dermer Saas-Fee Lecture 9 15-20 March 2010

  6. Maximum Electron Synchrotron Photon Energy Electron synchrotron energy-loss rate: In Fermi acceleration scenarios, acceleration timescale > Larmor timescale: Mean synchrotron photon energy radiated by an electron with Lorentz factor g in a magnetic field of strength B: 230 MeV Dermer Saas-Fee Lecture 9 15-20 March 2010

  7. Ultra-high Energy Cosmic Rays Radiation flux in space Dermer Saas-Fee Lecture 9 15-20 March 2010

  8. Ultra-high Energy Cosmic Ray Spectrum Knee Feature at 3×1015 eV Second Knee at 4×1017 eV Ankle Feature at 5×1018 eV GZK Cutoff at 6×1019 eV (predicted by Greisen, Zatsepin, and Kuzmin in 1968) Cosmic-ray astronomy: Origin of the Cosmic Rays Cosmic-ray Spectrum Cosmic-ray Anisotropy Dermer Saas-Fee Lecture 9 15-20 March 2010 2-1 through 2-n of N

  9. Hillas Condition Hillas 1984 Hillas condition: Larmor radius < size scale of system Fermi acceleration: highest energy particles made by sources with largest luminosity (Emax < L1/2/G) 1st-order shock acceleration 2nd-order stochasticacceleration through plasma turbulence (compare other mechanisms: electrostatic, magnetic reconnection) g-ray astronomy: Eg >~ 20 TeV in sources beyond galaxy (EBL absorption) Cosmic-ray astronomy: E >~ 3×1020 eV Dermer Saas-Fee Lecture 9 15-20 March 2010

  10. Extragalactic Origin of UHECRs • Hillas Condition: Sources of UHECRs must have rL < source size • Rules out many classes of potential UHECR sources, flare stars, white dwarfs, “normal” neutron stars, Galactic sources (if protons),… Galactic Disk Magnetic Field: 2 – 5 mG Thickness ~ 200 pc Galactic Halo Magnetic Field: 0.1 mG Thickness ~ 1 – 5 kpc Hillas 1984 Particle with energy E = 60 EeV = 60x1018 eV Dermer Saas-Fee Lecture 9 15-20 March 2010

  11. 2007 — Birth (?) of Charged Particle Astronomy Arrival directions of 27 UHECRs >6×1019 eV; open circles) correlated with 318 AGN (×)within 75 Mpc, Cen A, radio-loud and radio-quiet AGN Deflection in Galactic magnetic field  protons or light nuclei Arrival directions correlated with supergalactic plane Dermer Saas-Fee Lecture 9 15-20 March 2010

  12. Auger Data: 2009 58 events: July, 2009 (with Swift-BAT AGN density map) 27 events as of November 2007 Dermer Saas-Fee Lecture 9 15-20 March 2010

  13. HiRes Collaboration 2008 Auger Collaboration 2009 GZK Effect and Composition Depth of shower maximum and Fluctuations of Xmax HiRes Collaboration disputes trend to heavy composition above 1019 eV Dermer Saas-Fee Lecture 9 15-20 March 2010

  14. Photopion Production Cross section • Photopion pg production cross section Mücke et al. 2000 Atoyan & Dermer (2003) Dermer Saas-Fee Lecture 9 15-20 March 2010

  15. Calculate Photopion Energy Losses of CR Protons with CMB • ethr = 390 2mp/me Dermer Saas-Fee Lecture 9 15-20 March 2010

  16. Analytic vs. Numerical Photopion Energy Losses with CMB • Analytic Asymptotes Dermer Saas-Fee Lecture 9 15-20 March 2010

  17. Horizon distance vs. MFP: Linear distance where proton with measured energy E had energy eE GZK Horizon Distance for Protons CMBR only: Auger limits: GZK cutoff consistent with UHECR protons Dermer Saas-Fee Lecture 9 15-20 March 2010

  18. UHECR Emissivity knee ankle (Waxman 1995, Vietri 1995) Sources of (>1018 eV) UHECRs need to have a local luminosity density (emissivity) of 1044 ergs/Mpc3-yr Dermer Saas-Fee Lecture 9 15-20 March 2010

  19. 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 Saas-Fee Lecture 9 15-20 March 2010

  20. Low Luminosity GRB Emissivity Liang, Zhang et al. 2007 (emissivity of outflow kinetic energy; not g rays) Wang, Razzaque, et al. 2007 Dermer Saas-Fee Lecture 9 15-20 March 2010

  21. 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 Saas-Fee Lecture 9 15-20 March 2010

  22. Particle Acceleration to Ultra-High Energies by GRBs by Fermi processes Proper frame (´) energy density of relativistic wind with apparent luminosity L R Maximum particle energy G Lorentz contraction: Dermer Saas-Fee Lecture 9 15-20 March 2010

  23. L-G diagram • Sources with jet Lorentz factor G must have jet power L exceeding the heavy solid and dot-dashed curves to accelerate protons and Fe respectively, to E = 1020 eV. • Upper limits to L and G are defined by competition between synchrotron losses and acceleration time (dashed lines), and synchrotron losses and available time (dotted lines). • Variability times tv = 104 s and 1 ms, and G = 10 and 103, are used for UHECR proton acceleration in blazars and GRBs, respectively. • LLGRBs? Dermer Saas-Fee Lecture 9 15-20 March 2010

  24. How Realistic is the L-G Diagram? Treat Colliding Shells Four Asymptotic Regimes Conditions for Acceleration to highest energies Dermer Saas-Fee Lecture 9 15-20 March 2010

  25. Relativistic Shock Hydrodynamics • Solve strong shock jump conditions for s • Number flux conservations: nbG • Energy conservation: (nmpc2+ p) bG2 cloud shell Forward-shocked fluid cloud shell Reverse-shocked fluid Sari and Piran (1995) Dermer Saas-Fee Lecture 9 15-20 March 2010

  26. Equality of kinetic energy densities at contact discontinuity Reverse Shock Physics n(x)1/x2, reverse shock speed increases with radius: • Two Regimes: • Nonrelativistic Reverse Shock (NRS) • Relativistic Reverse Shock (RRS) Provided reverse shock crosses shell before reverse shock becomes relativistic Solving: Dermer Saas-Fee Lecture 9 15-20 March 2010

  27. Cumulative Emissivity of Gamma-Ray Galaxies from Fermi • Need Adequate Emissivity and Sources within GZK radius • Need Adequate Power (rejects star-forming galaxies) • Fermi data favors ion acceleration by BL Lacs/FR1 radio galaxies • GRB origin requires nanoGauss IGM; ion escape difficult • 1LAC AGNs • FSRQs • BL Lac • Misaligned Radio Galaxies • Starburst (and Star-forming) Dermer Saas-Fee Lecture 9 15-20 March 2010

  28. Requirements on IGM Field from GRB Space Densityfor a Long Duration GRB Origin of UHECRs • Long GRB rate 2fb Gpc-3 yr-1 at the redshift z  1–2 • 10 × smaller at 100d100 Mpc due to the star formation rate factor • 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 Saas-Fee Lecture 9 15-20 March 2010

  29. Summary Fermi results give minimum values of apparent jet luminosity and bulk outflow Lorentz factor which, in Fermi acceleration scenarios, imply maximum accelerated particle energies L-G diagram and cumulative emissivity constrain allowed sites of UHECRs Fermi results consistent with UHECR ions accelerated from FR1 and BL Lac objects; UHECRs could still be accelerated by GRBs depending on rate density and intergalactic magnetic field within GZK radius The most energetic and powerful radiations in nature are made by particles accelerated through Fermi processes in black-hole jets powered by rotation. Dermer Saas-Fee Lecture 9 15-20 March 2010

  30. problems, problems • g rays from symbiotic star systems • TeV hardening in radio galaxies • Unification of blazars and radio galaxies • Accurate spectral modeling of systems with cosmic-ray interactions • Demodulated spectrum of cosmic rays • Extragalactic diffuse from star-forming galaxies • ms pulsars in globular clusters vs. field ms pulsars • X-ray/GeV/TeV correlations in LS 5039 • GeV/TeV emission from pair halos • Blazar sequence and blazar SED • Electron acceleration for young SNRs, hadronic acceleration for middle-aged SNRs • … It’s easy to make a problem hard, but hard to make a problem easy Dermer Saas-Fee Lecture 9 15-20 March 2010

  31. Merci beaucoup et au revoir; see you at the next meeting or wherever Dermer Saas-Fee Lecture 9 15-20 March 2010

  32. The end Dermer Saas-Fee Lecture 9 15-20 March 2010

  33. Backup slide Dermer Saas-Fee Lecture 9 15-20 March 2010

  34. Sensitivities of High Energy Instruments 100 MeV ×10-6 ph(>100 MeV)/cm2-s = 1.6×10-10 erg/cm2-s -2 spectrum INTEGRAL SPI Fermi

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