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The signature of the nearby universe on the very high energy (diffuse) gamma sky

The signature of the nearby universe on the very high energy (diffuse) gamma sky. Bergen, November 2006. Troels Haugbølle. haugboel@phys.au.dk. Collaborators: Alessandro Cuoco, Hannestad S, Miele G, Serpico P D, Tu H. Institute for Physics & Astronomy, Århus University.

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The signature of the nearby universe on the very high energy (diffuse) gamma sky

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  1. The signature of the nearby universe on the very high energy (diffuse) gamma sky Bergen, November 2006 Troels Haugbølle haugboel@phys.au.dk Collaborators: Alessandro Cuoco, Hannestad S, Miele G, Serpico P D, Tu H Institute for Physics & Astronomy, Århus University

  2. The diffuse cosmic gamma ray sky(as seen by EGRET) Energy spectra Angular distribution

  3. Why interest us for the diffuse -ray sky? • Glast is flying very soon (fall 2007) (energy range 10 MeV -> 500 GeV)

  4. Why interest us for the diffuse -ray sky? • Glast is flying very soon (fall 2007) (energy range 10 MeV -> 500 GeV) • Several ground based surveys are in operation or planned • Milagro, HAWC, ARGO... Energy range > 500 GeV

  5. Why interest us for the diffuse -ray sky? • Glast is flying very soon (fall 2007) (energy range 10 MeV -> 500 GeV) • Several ground based surveys are in operation or planned • Milagro, HAWC, ARGO... Energy range > 500 GeV • Using the angular distribution and spectra of the flux, we can learn about the sources - be it AGNs, micro quasars, pulsars, decaying dark matter or ...

  6. MAGIC(Germany, Spain, Italy)Summer 20031 telescope 17 meters Ø VERITAS(USA & England)2005?7 telescopes10 meters Ø Montosa Canyon, Arizona Roque delos Muchachos, Canary Islands CANGAROO III(Australia & Japan)Spring 20044 telescopes 10 meters Ø Windhoek, Namibia HESS(Germany & France)Summer 20024 (16) telescopes 12 meters Ø Woomera, Australia Other gamma-ray observatories(with small field-of-view though)

  7. 10 TeV 1 TeV 100 GeV Gamma Ray Propagation Photon interactions at TeV energies give a gamma horizon comparable in size to the GZK horizon The main interaction is:  -> e+e- Pair production with e+e- cascading. The gamma photons scatter on the extra- galactic background light. =1

  8. Window Function 300GeV W 1TeV 3TeV z Gamma Ray Propagation Given the density  of sources and the energy spectrum g[E] the intensity is For low z the flux above an threshold energy Ecut is where W(E,z) is the window function

  9. Using the large scale structure to predict the distribution of the -ray flux The SDSS survey 1Gpc

  10. Using the large scale structure to predict the distribution of the -ray flux The SDSS survey 1Gpc

  11. The large scale structure- on a sphere -

  12. The large scale structure- on a sphere -

  13. The PSCz survey Mask and sky distribution of the PSCz sources Redshift distribution and selection function Quality compared to the 2MASS: • About 15.000 Gal. in PSCz against 1.5 millions in 2MASS, and less sky coverage. • ...but better redshifts quality: Spectroscopic redshifts available in PSCz with negligible errors • For 2MASS only photometry is available from which photometric redshifts are calculable only with great errors (typically 20-30%)

  14. + Window Function 3GeV W = 1TeV 3TeV z Combine W(E,z) and survey

  15. Synthetic sky maps(low-l angular powerspectrum)

  16. Synthetic sky maps(low-l angular powerspectrum) Green band: 1- Shot noise Points: alm from PSCz

  17. The angular powerspectrum for high l N-body Simulation Using N-Body simulations or the Halo model we can repeat the analysis of the PSCz catalog. But without masks, noise, or resolution problems. Halo Model

  18. Summary • Observations: GLAST is flying soon. Ground based survey telescopes are planned or working • Theory: Due to pair production the very high energy gamma rays originate at low redshift • Hypothesis: Sources are sitting in the cosmic web. But how are they correlated with matter? • Analysis: Using large redshift surveys with well understood systematics, we can make skymaps of the diffuse ray sky in different scenarios • Prediction: Using N-body/halo models we can predict the form of the angular powerspectrum for high l. Using surveys we can predict the low l • Conclusion: Correlating the -ray sky with the large scale structure we learn about the sources

  19. Summary • Observations: GLAST is flying soon. Ground based survey telescopes are planned or working • Theory: Due to pair production the very high energy gamma rays originate at low redshift • Hypothesis: Sources are sitting in the cosmic web. But how are they correlated with matter? • Analysis: Using large redshift surveys with well understood systematics, we can make skymaps of the diffuse ray sky in different scenarios • Prediction: Using N-body/halo models we can predict the form of the angular powerspectrum for high l. Using surveys we can predict the low l • Conclusion: Correlating the -ray sky with the large scale structure we learn about the sources Green band: 1- Shot noise Points: alm from PSCz

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