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Very High Energy Gamma Ray Astronomy: A New Window to the Universe

isanne avatar
isanne
54 diapositives · 688 Views · Oct 01, 2014

Explore the groundbreaking advancements in very high energy gamma-ray astronomy, including imaging atmospheric Cherenkov telescopes, sources like Active Galactic Nuclei and Crab Nebula, and the search for cosmic ray accelerators. Discover the mysteries of supernovae and cosmic rays in this fascinating field of study.

#very high energy gamma ray astronomy: a new window to the universe #very high energy gamma ray astronomy: a new window to the universe ppt #powerpoint #presentation
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  1. Very High Energy Gamma Ray Astronomy- A new window to the Universe –Christian StegmannUniversity of Erlangen-NurembergHumboldt University BerlinXXV Physics in Collisions, Prague 2005

  2. The sky at energies of 1 eV

  3. The Galactic Centre Active Galactic Nuclei The Crab nebula The strongest TeV source Flux ~1 Photon/km2/s Supernovae The accelerators of Cosmic rays? The sky at energies of 1 TeV Terra Incognita Surprises and progress in 2004/2005 Pulsars, unknown sources, scans … Status PIC 2004 Stärkste Quelle 1 photon km-2s-1

  4. The main playersImaging Atmospheric Cherenkov Telescopes

  5. Photon Particle shower ~ 10 km ~ 1o Cherenkov light ~ 120 m Detection of gamma-rays via the Cherenkov light from air showers Intensity  shower energy Image orientation  shower direction Image shape  primary particle

  6. Stereoscopic Observation Technique Source position

  7. Cherenkov Telescopes Worldwide Veritas MAGIC artist view H.E.S.S. CANGAROO III

  8. Cherenkov Telescopes Worldwide

  9. My personal highlights in 2004

  10. My personal highlights in 2004 The supernova remnant RX J1713.7-3946 Nature 432, 75 (2004) H.E.S.S. First ever astronomical gamma-ray image

  11. Scan region My personal highlights in 2004 H.E.S.S.: First sensitive scan of the inner Galaxy

  12. My personal highlights in 2004 8 new sources! Science 307, 1938 (2005)

  13. Galactic Sources

  14. Veritas 2.6 gammas/minute 10.1 sigma/sqrt(time in hours) Crab Nebula • Supernova from 1054 A.D. • 6500 Ly distance • 33 ms pulsar • Plerion • relativistic electron plasma heated by the central pulsar • The standard candle of gamma-ray astronomy • Seen by all instruments VLT, optical

  15. Electron Inverse Compton scattering Synchrotron radiation  Electron  Crab Nebula Krebs Nebel

  16. Electron Inverse Compton scattering Synchrotron radiation  Electron  Crab Nebula Krebs Nebel H.E.S.S. preliminary

  17. Shell type supernova remnants Cas A, Chandra, Röntgen

  18. Cosmic Ray Accelerators? • Why supernova remnants? • large energy release (dE/dt)SN = 10.(dE/dt)CR • acceleration in shock waves • element composition of Cosmic Rays • Why gamma-rays? • Electrons: -radiation via IC • Hadrons: 0 • pointing • Search strategies • non-thermal X-rays • scans Cas A, Chandra, X-rays

  19. CANGAROO II (TeV) Point source The supernova remnant RX J1713.7-3946 ROSAT (keV) Age ~1500 years

  20. H.E.S.S. 2004 33 h with 4 Telescopes 210 GeV threshold point source

  21. point source H.E.S.S. 2004 33 h with 4 Telescopes 210 GeV threshold

  22. Energy spectrum One-zone model Power law dN/dE = K E-α Spectral index: α = 2.2 preliminary

  23. Implications Unambiguous proof that supernova shock waves are cosmic accelerators; they accelerate particles to O(100 TeV) But are they the sources of (nucleonic) cosmic rays ? Is the kinetic energy released in the explosion converted to cosmic-ray energy with O(10%) efficiency ?

  24. B B Stars Cosmic proton accelerators Dust Cosmic electron accelerators Synchrotron radiation Inverse Compton Bremsstrahlung Electron or hadron accelerator? radio infrared visible light X-rays VHE -rays E2 dN/dE ln(E)

  25. Injection spectrum: power law with cutoff “low” magnetic field target density Electron accelerator radio X-rays VHE -rays F.A. Aharonian E2 dN/dE (erg cm-2 s-1) log(E/eV)

  26. Electron accelerator radio X-rays VHE -rays E2 dN/dE (erg cm-2 s-1) log(E/eV)

  27. X-ray photon index G. Cassam-Chenaï A&A 427, 199 (2004) Spatially resolved spectra H.E.S.S. preliminary TeV photon index

  28. Proton accelerator F.A. Aharonian • Continuous proton injection over 1000 years • Injection spectrum: power law, index ~2 • Different cutoff shapes

  29. Power law index 2.1 ROSAT Vela Junior H.E.S.S. 2004 ~3 h H.E.S.S. 2005 preliminary ~10 h (see also CANGAROO ApJ, 619, L163-L165 (2005) )

  30. HESS J1834-087 HESS J1804-216 HESS J1640-465 • More possible SNR associations • Separation of electron and hardon component • Multi-wavelength observations • Correlation with molecular clouds “Beam width”

  31. The binary systemPSR B1259-63/SS 2883The first variable galactic TeV-source

  32. The binary system PSR B1259-63 / SS 2883 Periastron 7. March 2004 Be Star 10 M Discovery (March 2004): Complex interaction between pulsar and star during periastron 48 ms Pulsar 3.4 y period

  33. Periastron Flux >380 GeV [cm-2 s-1] The PSR B1259-63 field of view H.E.S.S. Feb. 04 March 04 Apr./May 04

  34. Source HESS J1303-631 • is extended • has constant flux • no association with radio • or X-ray source! • other unknown sources: • TeV J2032+4130 (HEGRA) • HESS J1616-508 HESS J1616-508 The PSR B1259-63 field of view HESS J1303-631 What are these “dark” accelerators? Feb. 04 März 04 Apr./Mai 04

  35. The Galactic Centre

  36. Chandra GC survey NASA/UMass/D.Wang et al. Chandra GC survey NASA/UMass/D.Wang et al. CANGAROO (80%) CANGAROO (80%) H.E.S.S. H.E.S.S. (95%) Whipple (95%) Whipple (95%) Contours from Hooper et al. 2004 The Galactic Centre Seen by CANGAROO Whipple/Veritas H.E.S.S.

  37. HESS J1745-290 35  significance Das Galaktische Zentrum H.E.S.S. 2004 50 h with 4 telescopes preliminary

  38. Sgr A East SNR Systematic pointing error Sgr A* Radio TeV H.E.S.S. Sagittarius A H.E.S.S. 2004 preliminary

  39. TeV H.E.S.S. Sagittarius A H.E.S.S. 2004 preliminary Point-like core Extended tail Distance to Sgr A* 14′′±30′′ galactic longitude 12′′±30′′ galactic latitude Sgr A East not excluded

  40. Gamma ray spectrum • Power law, index 2.3 • No significant variability Preliminary

  41. 3‘ Sgr A* Sgr A East HESS J1745-290 • Either Sgr A* ... • Supermassive (M  3.106 M) rotating black hole in a magnetic field •  huge electromotive force (e.m.f.) • able to accelerate protons up to1018 eV (0) • or electrons (-rays via IC) • ... or Sgr A East • 10000 years old supernova • covers Sgr A* • Fermi-acceleration of Cosmic Rays in expanding shock wave or …

  42. … Dark matter annihilation ? For pure DM origin • rather large mass • large x-section or density • unusual spectrum or superposition of spectra H.E.S.S. 2004 Preliminary 20 TeV Neutralino 20 TeV Kaluza Klein particle

  43. Extragalactic Sources Active Galactic Nuclei

  44. Active Galactic Nuclei • Active Galactic Nuclei • Supermassive black holes, M109 M • Accretion disc with relativistic jet • Blazar-Typ: Jet towards Earth • Doppler-boost of emission spectra  TeV -radiation

  45.  e+ e-  dN/dE dN/dE E E Active Galactic Nuclei Absorption in extragalactic background light (Infrared) (TeV) + (IR)  e+e- Study of the infrared background light  Cosmology Physics of compact objects and relativistic jets and …

  46. -ray horizon Blanch & Martinez 2004 Different models for the extragalactic background light (EBL) simulated Measurements H.E.S.S., CANGAROO, Veritas MAGIC

  47. AGN Physics Mkn 421 multi-wavelength spectra e.g. Mkn 421 (z=0.031) Emission spectra • Synchrotron-Self-Compton • Flares • Intrinsic Cut-offs F [erg cm-2 s-1] Konopelko et al. ApJ 597 (2003) 851 Many sources at large z Many sources at the same z  [Hz] Mkn 421 flares 2004 Mkn 421 Cut-offs Flux [10-11cm-2 s-1] Ecut [TeV] H.E.S.S. 2004 H.E.S.S. 2004 Flux(E>2TeV) [cm-2 s-1] MJD

  48. MAGIC H.E.S.S. Index = 2.1±0.1±0.3 ECut = 3.1±0.5±0.9 TeV Simultaneous Observations e.g. MAGIC & H.E.S.S. Simultaneous observation of a large energy range e.g. Mkn 421 flare in 2003/2004 MAGIC H.E.S.S.

  49. ground state PKS 2155-304 H.E.S.S. N.Tonello, T202.1 -ray horizon Mrk421 (H.E.S.S., MAGIC) Mrk501 1ES 1959+650 (MAGIC) PKS 2155-304 (H.E.S.S.) H1426+428

  50. AGN limits • 19 BL Lacs and other AGNs • z between 0.002 and 0.3 • 1-5 h obs. time • limits 1-3% of Crab flux H.E.S.S. Mkn 501 Significance Significance