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Measuring the proper motion of microhalos using their potential  -ray signal

Measuring the proper motion of microhalos using their potential  -ray signal. Savvas M. Koushiappas T-6 & ISR-1 Los Alamos National Laboratory. Phys. Rev. Lett. In press (astro-ph/0606208). What can be learned from a gamma-ray all sky map?.

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Measuring the proper motion of microhalos using their potential  -ray signal

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  1. Measuring the proper motion of microhalos using their potential -ray signal Savvas M. Koushiappas T-6 & ISR-1 Los Alamos National Laboratory Phys. Rev. Lett. In press (astro-ph/0606208)

  2. What can be learned from a gamma-ray all sky map? • A lot of astrophysics (compact binaries, active galactic nuclei, supernova remnants, gamma-ray bursts, etc.)

  3. What can be learned from a gamma-ray all sky map? • A lot of astrophysics (compact binaries, active galactic nuclei, supernova remnants, gamma-ray bursts, etc.) • Backgrounds: Resolved (populations of sources), Diffused (look at angular fluctuations for clues). Miniati, Koushiappas & Di Mateo, in preparation

  4. What can be learned from a gamma-ray all sky map? • A lot of astrophysics (compact binaries, active galactic nuclei, supernova remnants, gamma-ray bursts, etc.) • Backgrounds: Resolved (populations of sources), Diffused (look at angular fluctuations for clues). • DARK MATTER: Galactic center,

  5. What can be learned from a gamma-ray all sky map? • A lot of astrophysics (compact binaries, active galactic nuclei, supernova remnants, gamma-ray bursts, etc.) • Backgrounds: Resolved (populations of sources), Diffused (look at angular fluctuations for clues). • DARK MATTER: Galactic center, other galaxies

  6. What can be learned from a gamma-ray all sky map? • A lot of astrophysics (compact binaries, active galactic nuclei, supernova remnants, gamma-ray bursts, etc.) • Backgrounds: Resolved (populations of sources), Diffused (look at angular fluctuations for clues). • DARK MATTER: Galactic center, other galaxies, Milky Way substructure Koushiappas, Zentner & Walker, PRD 69, 043501 (2004)

  7. What can be learned from a gamma-ray all sky map? • A lot of astrophysics (compact binaries, active galactic nuclei, supernova remnants, gamma-ray bursts, etc.) • Backgrounds: Resolved (populations of sources), Diffused (look at angular fluctuations for clues). • DARK MATTER: Galactic center, other galaxies, Milky Way substructure, microhalos!

  8. Microhalos: Why are they interesting? A possible detection can provide information about theparticle physicsproperties of the dark matter particle. A measured abundance in the Milky Way halo contains information on thehierarchical assembly of dark matter halos at very early times(survival/disruption), a task that is unattainable by any other method. Smallest microhalos are set by the kinetic decoupling temperature of the dark matter particle Kinetic equilibrium Green, Hofmann & Schwarz, MNRAS 353, 123 (2004) Profumo, Sigurdson & Kamionkowski, PRL 97, 031301 (2006)

  9. First collapsed dark matter structures Diemand, Moore & Stadel, Nature, 433, 389 (2005) Green, Hofmann & Schwarz, MNRAS 353, 123 (2004) NFW Smaller mass scale van den Bosch, Tormen & Giocoli, MNRAS 359, 1029 (2005), but see also Zentner & Bullock, ApJ 598, 49 (2003) Diemand, Kuhlen & Madau, ApJ in press (astro-ph/0603250) Diemand et al., Nature 433, 389 (2005)

  10. First collapsed dark matter structures Diemand, Moore & Stadel, Nature, 433, 389 (2005) Green, Hofmann & Schwarz, MNRAS 353, 123 (2004) NFW Smaller mass scale Effect of multiple stellar encounters b=0.02pc Goerdt et al, astro-ph/0608495 Effect of different impact parameters Goerdt et al, astro-ph/0608495

  11. SUSY CDM Lightest neutralino Line Continuum B A B B stuff More stuff A jet A jet More stuff stuff

  12. Two ideas: 1) Dark matter microhalos 2) Dark matter couples to photons Can we test them?

  13. Sun

  14. Earth Sun 

  15. Earth Sun 

  16. Earth Sun 

  17. Earth Sun 

  18. Earth Earth Sun 

  19. Earth Earth Sun 

  20. Earth Sun 

  21. Visibility condition D 

  22. Proper motion detectability condition   4’ 4’ R

  23. Ex: SUSY CDM, if the decoupling temperature is 10 MeV, then microhalos of mass greater than will perhaps be present in the Milky Way halo. If 20% of them survive, then ~200 will be visible, and 8 of those 200 will exhibit a detectable proper motion.

  24. For the case of SUSY CDM, if at least 1 moving source is detected in an all sky gamma-ray GLAST map after a 2-year integration, then the decoupling temperature of the CDM particle must be less than 100 MeV and the mass of the WIMP must be less than 600 GeV.

  25. For the case of SUSY CDM, if at least 1 moving source is detected in an all sky gamma-ray GLAST map after a 2-year integration, then the decoupling temperature of the CDM particle must be less than 100 MeV and the mass of the WIMP must be less than 600 GeV. Profumo, Sigurdson & Kamionkowski, PRL 97, 031301 (2006)

  26. At small microhalo masses, the number of microhalos with proper motion is limited by the non-abundance of microhalos within a visibility volume At large microhalo masses: mean distance between microhalos is larger, so probablility of one being nearby is small

  27. At small microhalo masses, the number of microhalos with proper motion is limited by the non-abundance of microhalos within a visibility volume Excess photon count from adjacent resolution bins in extented microhalos could be used to better localise the position of the microhalo At large microhalo masses: mean distance between microhalos is larger, so probablility of one being nearby is small Increasing the angular resolution threshold for proper motion detection increases the total number of detected microhalos!

  28. Summary There is a minimum dark matter halo mass set by the dark matter particle physics For the case of SUSY dark matter, this mass is Dark matter candidates (such as SUSY CDM) can annihilate to -ray photons Search for the proper motion of these objects in all-sky gamma-ray surveys (e.g. GLAST)

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