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Dark Matter visible by Galactic Gamma Rays?

We don ’t know it, because we don’t see it!. WdB, C. Sander, V. Zhukov, A. Gladyshev, D. Kazakov, EGRET excess of diffuse Galactic Gamma Rays as Tracer of DM , astro-ph/0508617, A&A, 4 44 (2005) 51. Dark Matter visible by Galactic Gamma Rays?. OUTLINE

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Dark Matter visible by Galactic Gamma Rays?

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  1. We don’t know it, because we don’t see it! WdB, C. Sander, V. Zhukov, A. Gladyshev, D. Kazakov, EGRET excess of diffuse Galactic Gamma Rays as Tracer of DM, astro-ph/0508617, A&A, 444 (2005) 51 Dark Matter visible by Galactic Gamma Rays? • OUTLINE • Determination of the WIMP mass • Determination of the WIMP halo • Determination of the rotation curve • OBJECTIONS: • Antiproton fluxes • PREDICTIONS • for DM searches • for LHC • for neutrino telescopes

  2. http://www.sciam.com/ August 22, 2006 Colliding Clusters Shed Light on Dark Matter • Observations with bullet cluster: • Chandra X-ray telescope shows distribution of hot gas • Hubble Space Telescope and others show distribution of Dark Matter • from gravitational lensing • Distributions are clearly different after collision-> • Dark Matter is weakly interacting!

  3. T>>M: f+f->M+M; M+M->f+f T<M: M+M->f+f T=M/22: M decoupled, stable density (wenn Annihilationrate  Expansions- rate,i.e. =<v>n(xfr)  H(xfr) !) Thermal history of WIMPs Thermal equilibrium abundance Actual abundance Comoving number density WMAP -> h2=0.1130.009 -> <v>=2.10-26 cm3/s DM increases in Galaxies: 1 WIMP/coffee cup 105 <ρ>. DMA (ρ2) restarts again.. Annihilation into lighter particles, like Quarks and Leptons -> 0’s -> Gammas! T=M/22 Only assumption in this analysis: WIMP = THERMAL RELIC! x=m/T Jungmann,Kamionkowski, Griest, PR 1995

  4.   f f f ~ f A Z    f f f   W Z 0    Z W Example of DM annihilation (SUSY) ≈37 gammas Quark-Fragmentation known! Hence spectra of positrons, gammas and antiprotons known! Relative amount of ,p,e+ known as well. Dominant  +   A  b bbar quark pair Sum of diagrams should yield <σv>=2.10-26 cm3/s to get correct relic density

  5. Idea of indirect detection analysis Idea: Thermal relics disappeared by annihilation. (From WMAP Annihilation cross section <σv>=2.10-27/Ωh2) Annihilation into quarks with this x-section should yield large amount of Gamma Rays (37 γ’s/Annihilation from LEP data) Gamma spectrum from DMA significantly harder than dominant background from inelastic pp collisions (Cosmic Rays on H-gas) Background shape KNOWN from fixed target experiments, DMA Gamma Ray shape KNOWN from LEP data EGRET Data indeed shows such an expected excess with SAME spectral SHAPE IN ALL SKY directions and INTENSITY of excess allows to measure DM distribution in GALAXY. Then one knows MASS distribution of DM and visible matter and can calculate ROTATION CURVE (RC). IF GAMMA RAYS indeed originate from DMA, then this can be proven by calculating shape of RC from gamma rays! WdB, C. Sander, V. Zhukov, A. Gladyshev, D. Kazakov, EGRET excess of diffuse Galactic Gamma Rays as Tracer of DM, astro-ph/0508617, A&A, 444 (2005) 51

  6. EGRET on CGRO (Compton Gamma Ray Observ.)Data publicly available from NASA archive Instrumental parameters: Energy range: 0.02-30 GeV Energy resolution: ~20% Effective area: 1500 cm2 Angular resol.: <0.50 Data taking: 1991-1994 Main results: Catalogue of point sources Excess in diffuse gamma rays

  7. π0 π0 WIMPS IC IC Brems Brems The EGRET excess of diffuse galactic gamma rays without and with DM annihilation Fit only KNOWN shapes of BG + DMA, i.e. 1 or 2 parameter fit NO GALACTIC models needed. Propagation of gammas straightforward If normalization free, only relative point-to-point errors of ≤7% important, not absolute normalization error of 15%. Statistical errors negligible.

  8. Quarks from WIMPS Quarks in protons What about background shape? No SM No SM Protons Electrons Background from nuclear interactions (mainly p+p-> π0 + X ->  + X inverse Compton scattering (e-+  -> e- + ) Bremsstrahlung (e- + N -> e- +  + N) Shape of background KNOWN if Cosmic Ray spectra of p and e- known

  9. Energy loss times of electrons and nuclei t-1 = 1/E dE/dt univ Protons diffuse for long times without loosing energy! If centre would have harder spectrum, then hard to explain why excess in outer galaxy has SAME shape (can be fitted with same WIMP mass!)

  10. Background + signal describe EGRET data!

  11. Analysis of EGRET Data in 6 sky directions C: outer Galaxy A: inner Galaxy B: outer disc Total 2 for all regions :28/36  Prob.= 0.8 Excess above background > 10σ. E: intermediate lat. F: galactic poles D: low latitude A: inner Galaxy (l=±300, |b|<50) B: Galactic plane avoiding A C: Outer Galaxy D: low latitude (10-200) E: intermediate lat. (20-600) F: Galactic poles (60-900)

  12. SUPERSYMMETRIC DARK MATTER AND THE EXTRAGALACTIC GAMMA RAY BACKGROUND 2/d.o.f=10.9/6  P=0.1 2/d.o.f=4.7/4  P=0.3 m =50 GeV W.de Boer et al., Phys.Rev. Lett..95:209001,2005 D. Elssässer and K. Mannheim, Phys.Rev.Lett.94:171302,2005

  13. bulge disk sun Fits for 180 instead of 6 regions 180 regions: 80in longitude  45 bins 4 bins in latitude  00<|b|<50 50<|b|<100 100<|b|<200 200<|b|<900  4x45=180 bins  >1400 data points. Reduced 2≈1 with 7% errors

  14. Expected Profile Observed Profile z xy xy Rotation Curve 2002,Newberg et al. Ibata et al, Crane et al. Yanny et al. x y 1/r2 halo totalDM disk xz xz bulge Inner Ring Outer Ring 1/r2 profile and rings determined from inde-pendent directions Normalize to solar velocity of 220 km/s Dark Matter distribution v2M/r=cons. and (M/r)/r2 1/r2 for const. rotation curve Divergent for r=0? NFW1/r Isotherm const. Halo profile

  15. Rotation curve of Milky Way Honma & Sofue (97) Schneider &Terzian (83) Brand & Blitz(93)

  16. Do other galaxies have bumps in rotation curves? Sofue & Honma

  17. Tidal disruption of dwarf galaxy in gravitational field of larger galaxy From Eric Hayashi

  18. H2 Inner Ring coincides with ring of dust and H2 -> gravitational potential well! 4 kpc coincides with ring of neutral hydrogen molecules! H+H->H2 in presence of dust-> grav. potential well at 4-5 kpc. Enhancement of inner (outer) ring over 1/r2 profile 6 (8). Mass in rings 0.3 (3)% of total DM

  19. Astrophysicists: What is the origin of “GeV excess” of diffuse Galactic Gamma Rays? Astronomers: Why a change of slope in the galactic rotation curve at R0 ≈ 11 kpc? Why ring of stars at 14 kpc? Why ring of molecular hydrogen at 4 kpc? Cosmologists: How is DM annihilating?A: into quark pairs How is Cold Dark Matter distributed? Particle physicists: Is DM annihilating as expected in Supersymmetry? 7 Physics Questions answered SIMULTANEOUSLY if WIMP = thermal relic A: DM annihilation A: DM substructure A: standard profile + substructure A: Cross sections perfectly consistent with mSUGRA for light gauginos, heavy squarks/sleptons

  20. Objections against DMA interpretation 1) Does antiproton rate exclude interpretation of EGRET data? (L.B.) Bergstrom et al. astro-ph/0603632, Abstract: we investigate the viability of the model using the DarkSUSY package to compute the gamma-ray and antiproton fluxes. We are able to show that their (=WdB et al) model is excluded by a wide margin from the measured flux of antiprotons. • Problem with DarkSUSY (DS): • Flux of antiprotons/gamma in DarkSUSY: O(1) from DMA. • However, O(10-3-10-2) from LEP data • Reason: DS has diffusion box with isotropic diffusion -> • DMA fills up box with high density of antiprotons • 2) More realistic models have anisotropic diffusion. • E.g. spiral galaxies have magnetic fields perpendicular to • disk-> antiprotons may spiral quickly out of Galaxy.

  21. Magnetic fields observed in spiral galaxies fieldline disk A few uG perpendicular to disc: Strong convection to disc? A few µG along spiral arms: Can lead to slow radial diffusion Isotropic diffusion assumes randomly oriented magnetic turbulences. Preferred magnetic field directions -> anisotropic diffusion

  22. Preliminary results from GALPROP with isotropic and anisotropic propagation Antiprotons B/C ratio Summary: with anisotropic propagation you can send charged particles whereever you want and still be consistent with B/C and 10Be/9Be

  23. EGRET EXCESS Statistical errors only Sofue &Honma R0=8.3 kpc v Inner rotation curve R0=7.0 Outer RC Black hole at centre: R0=8.00.4 kpc R/R0 Objections against DMA interpretation 2) Rotation curves in outer galaxy measured with different method than inner rotation curve. Can you combine? Also it depends on R0. Answer: first points of outer RC have same negative slope as inner RC so no problem with method. Change of slope seen for every R0. 3) Ringlike structures have enhanced density of hydrogen, so you expect excess of gamma radiation there. Why you need DMA? Answer: since we fit only the shapes of signal and BG, a higher gas density is automatically taken into account and DMA is needed to fit the spectral shape of the data. 4) Is EGRET data reliable enough to make such strong statements? Answer: EGRET spectrometer was calibrated in photon beam at SLAC. Calibration carefully monitored in space. Impossible to get calibration wrong in such a way that it fakes DMA. Halo profile only sensitive to relative EGRET uncertainties between different sky directions! MOST ERRORS DROP OUT!

  24. EGRET? Cross sections for Direct DM detection in mSUGRA mSUGRA: common masses m0 and m1/2 for spin 0 and spin ½ particles

  25. t t bb Annihilation cross sectionsin m0-m1/2 plane (μ > 0, A0=0) tanβ=50-55 Annihilation cross sections can be calculated,if masses are known (couplings as in SM). Assume not only gauge coupling Unification at GUT scale, but also mass unification, i.e. all Spin 0 (spin 1/2) particles have masses m0 (m1/2). For WMAP x-section of <v>2.10-26 cm3/s one needs For small LSP mass (m1/2 ≈ 175 GeV) large values of (m0 ≈ 1-2 Tev) (and large tan β ≈ 50) 10-24 EGRET WMAP  WW mSUGRA: common masses m0 and m1/2 for spin 0 and spin ½ particles

  26. SUSY Mass spectra in mSUGRA compatible with WMAP AND EGRET Charginos, neutralinos and gluinos light LSP largely Bino  DM may be supersymmetric partner of CMB

  27. Gauge unification perfect with SUSY spectrum from EGRET SM SUSY Update from Amaldi, dB, Fürstenau, PLB 260 1991 NO FREE PARAMETER With SUSY spectrum from EGRET + WMAP data and start values of couplings from final LEP data perfect gauge coupling unification! Also b->s and g-2 agree within 2σ with SUSY spectrum from EGRET

  28. EGRET and neutrino telescopes higgsinolike binolike Orloff et al., hep-ph/0301215

  29. Summary EGRET excess shows that WIMP is thermal relic with expected annihilation into quark pairs DM becomes visible by gamma rays from fragmentation (30-40 gamma rays of few GeV pro annihilation from π0 decays) Results rather model independent, since only KNOWN spectral shapes of signal and background used, NO model dependent calculations of abs.fluxes. Different models or unknown experimental problems may change boost factor and/or WIMP mass, BUT NOT the distribution in the sky. SPATIAL DISTRIBUTION of annihilation signal is signature for DMA which clearly shows that EGRET excess is tracer of DM by fact that one can CONSTRUCT ROTATION CURVE FROM GAMMA RAYS. Conventional models CANNOT explain above points SIMULTANEOUSLY, especially spectrum of gamma rays in all directions, 1/r2 profile, shape of rotation curve, ring of stars at 14 kpc and ring of H2 at 4 kpc, ….

  30. Summary of summary Indirect detection: intriguing hint for signal from DMA for 60 GeV WIMP Direct detection: expected to observe signal in near future IF we are not in VOID of clumpy DM halo LHC accelerator (2008-2018): cannot produce WIMPs directly (too small cross section), BUT IF WIMPs are Lightest Supersymmetric Particle (LSP) THEN WIMPs observable in DECAY of SUSY particles IF EVERY METHOD measures SAME WIMP mass, then PERFECT.

  31. Clustering of DM -> boosts annihilation rate Annihilation  SQUARE of DM density Clustersize: ≈ solar system? Mmin 10-8 -100 Mסּ? Steeply falling mass spectrum. Boost factor  <2>/<>2  2-20000 (Berezinski, Dokuchaev,..) From fit: B≈100 for WIMP of 60 GeV Clumps with Mmin -> dominant contribution -> MANY clumps in given direction -> same boostfactor in all directions

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