1 / 29

Can the WMAP haze really be a signature of annihilating neutralino dark matter?

Can the WMAP haze really be a signature of annihilating neutralino dark matter?. Daniel Cumberbatch (CWRU), Joe Zuntz (Oxford), Joe Silk (Oxford) and Hans Kristian Kamfjord Eriksen (Oslo). arXiv:0902.0039. Wilkinson Microwave Anisotropy Probe (WMAP). Cosmic Microwave Background (CMB)

neil
Télécharger la présentation

Can the WMAP haze really be a signature of annihilating neutralino dark matter?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Can the WMAP haze really be a signature of annihilating neutralino dark matter? Daniel Cumberbatch (CWRU), Joe Zuntz (Oxford), Joe Silk (Oxford) and Hans Kristian Kamfjord Eriksen (Oslo) arXiv:0902.0039 CWRU, February 2009

  2. Wilkinson Microwave Anisotropy Probe (WMAP) • Cosmic Microwave Background (CMB) • Temperature anisotropies • Polarization anisotropies • Cosmological parameter estimation • Galactic Foregrounds • Requires estimation before CMB signal extraction • Multiple sources • Dominant foregrounds: • Free-Free (Thermal Bremsstrahlung) • Thermal Dust • Synchrotron • Minimized in WMAP range (23 <  < 94 GHz) CWRU, February 2009

  3. WMAP Haze • Excess Free-Free emission from hot gas (T~105 K) • Gas thermally unstable • Insufficient gas abundance at 104 K (recombination lines) or 106 K (X-rays). • Exotic Sources of synchrotron emission • Ultra-relativistic electrons from supernovae • Dark Matter annihilation • SUSY neutralinos (Hooper ‘07) • Exciting DM (XDM) (Weiner ‘08) • Compact Composite Objects (CCO’s) (Zhitnitsky ‘08) • Sommerfeld-enhanced DM (Lattanzi ‘08) CWRU, February 2009

  4. Foregrounds: Free-Free • Free-Free (or thermal Bremsstrahlung) emission • Coulomb interactions between free e-and hot interstellar gas • Maps of H recombination line emission  EM •  H maps can trace morphology of Free-Free emission • Wisconsin H Mapper (WHAM) • Southern H Sky Survey Atlas (SHASSA) • Virginia Tech Spectral-Line Survey (VTSS) CWRU, February 2009 CWRU, February 2009

  5. Foregrounds: Free-Free • Correct H map for dust-extinction • assume uniform mixing of warm gas and dust • in E(B-V) magnitudes • Mask out regions A(H)=2.65E(B-V)>1 CWRU, February 2009

  6. Foregrounds: Dust • Thermal dust emission • Microscopic dust grains vibrating in thermal equilibrium with ambient radiation field • Finkbeiner Davis and Schlegel (FDS) @ 94 GHz may also trace electric dipole emission from smallest dust grains • Excited into rotational modes by collisions with ions CWRU, February 2009

  7. Foregrounds: Synchrotron • Mainly from e- near supernovae explosions • Shock-accelerated to relativistic (i.e. >MeV) energies • Subsequently lose energy from ICS (Starlight or CMB) and Synchrotron emission (Galactic Magnetic Field) • Measured best at v <1 GHz • Full-sky map at 408 MHz (Haslam et al.) CWRU, February 2009

  8. Template Fitting Solve Matrix Equation: Pa = w CWRU, February 2009

  9. Template Fitting • P ≠square • P ≠ linearly independent rows P ≠invertible by solving for pseudoinverseP+  Minimise CWRU, February 2009

  10. 3-template fit • Nside=64 • Beam Width=3 Determined by Gibbs Sampling • Multi-linear regression of free-free, dust and synchrotron templates r=Pa-w Unwanted sources • Residual Map  (Gibbs) (ILC) CWRU, February 2009

  11. 3-template fit  Remove point sources, re-fit … (K-Band) (Ka-Band) (Q-Band) CWRU, February 2009

  12. 3-template fit  2>1 significant Introduce 2: (Q-Band) (K-Band) (Ka-Band) 2K = 5.54 (6.59), 2Ka = 0.88 (1.45), 2Q = 1.08 (2.12) [Full-Sky] 2K = 14.69 (16.59), 2Ka = 1.65 (2.42), 2Q = 1.60 (2.84) [< 50] CWRU, February 2009

  13. 3-template fit • Using ratios of elements of a CWRU, February 2009

  14. 3-template fit • Correlation Matrix:  Haze is correlated with Synchrotron Emission CWRU, February 2009

  15. 3-template fit  Haze is statistically significant < 50 around GC  Haze is correlated with Synchrotron emission • Exotic component (e.g. Dark Matter) ??? • If so, would expect <50° ≠ >50°k  Allow for spatial variation in sync. by using multiple templates…  = 50 CWRU, February 2009

  16. 4-template fit  Minimise 2red. w.r.t.  using two Synchrotron templates (Gibbs) (ILC) CWRU, February 2009

  17. 4-template fit (Q-Band) (K-Band) (Ka-Band) ∆2K(%)=20.0 (18.7), ∆2Ka(%)=7.7 (6.8), ∆2Q(%)=6.3 (4.9) [FS] ∆2K(%)=46.0(45.5), ∆2Ka(%)=24.8(24.9), ∆2Q(%)=25.2(22.0) [<50] CWRU, February 2009

  18. 4-template fit • Using ratios of elements of a for synchrotron components CWRU, February 2009

  19. Dark Matter • WIMP DM candidates annihilate to e+/- +…other SM particles • DM annihilation Rate (r)2 hence increases towards GC e+/-propagate ISM e+/-interact with galactic magnetic field e+/-radiate via synchrotron (i.e. Haze) • Ingredients for DM contribution: • Calculate e+/- injection spectrum for WIMPs (i.e. per annihilation) • Calculate steady-statee+/- distribution in the galactic halo • Calculate fractional power of sync. rad. that e+/- of a given E contributes to a given frequency (e.g. K-band, 23GHz) • Calculate total flux radiated by e+/- along a given line of sight CWRU, February 2009

  20. Neutralino Models • Neutralino DM (LSP): • 4 Benchmark models: (Mixed) (Gaugino) (Gaugino) (Higgsino) CWRU, February 2009

  21. Steady-State e+/-distribution • Solve diffusion-loss equation: • Charged particles undergo random walk • Cylindrical (uniform) diffusion zone of depth 2L • Assume no re-acceleration of solar modulation CWRU, February 2009

  22. Steady-State e+/-distribution CWRU, February 2009

  23. Steady-State e+/-distribution CWRU, February 2009

  24. Synchrotron Radiation Spectrum • e+/-accelerated by galactic B-field, confined to helical paths • Lorentz factor =E/me • isotropic distribution of pitch angles  CWRU, February 2009

  25. Synchrotron Radiation Spectrum Only e+/-with 2>/B (i.e. x<1, E>12GeV) contribute significantly CWRU, February 2009

  26. Synchrotron Radiation Spectrum CWRU, February 2009

  27. DM Synchrotron Flux • Integrate along l.o.s. with inclination  wrt GC Synchrotron Power for individual e+/- CWRU, February 2009

  28. Results for DM Synchrotron Flux  Significant Boost Factors (BF) required for Haze! CWRU, February 2009

  29. Summary • There is a statistically significant residual emission surrounding GC remaining after fitting Free-Free, Dust and Sync. foregrounds. • Largely consistent results between Gibbs and ILC CMB estimators. • Haze can be significantly reduced by allowing for a slight spatial dependence in Synchrotron emission within 50° of GC, with a similar spectral dependence as that further out. • The DM contribution to the Haze depends sensitively on its fractional power to synchrotron emission for e+/-with 2>/B . • DM requires significant boosting in Synchrotron power (BF~100-1000) in order to account for Haze. • BF~100 may be obtainable from Dark Matter Substructures. CWRU, February 2009

More Related