can the wmap haze really be a signature of annihilating neutralino dark matter?

CWRU, February 2009

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)

Daniel Cumberbatch (CWRU), Joe Zuntz (Oxford),

Joe Silk (Oxford) and Hans Kristian Kamfjord Eriksen (Oslo)

arXiv:0902.0039

CWRU, February 2009

Wilkinson Microwave Anisotropy Probe (WMAP)

Wilkinson Microwave Anisotropy Probe (WMAP)

Cosmic Microwave Background (CMB) Temperature anisotropies Polarization anisotropies Cosmological parameter estimation

Cosmic Microwave Background (CMB) Temperature anisotropies Polarization anisotropies Cosmological parameter estimation

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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

WMAP HazeWMAP 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)

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



Foregrounds: Free-FreeForegrounds: 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)

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)

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I ∝ ne2dl∫ = Emission Measure (EM)

CWRU, February 2009

CWRU, February 2009



Foregrounds: Free-FreeForegrounds: 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

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τ =2.65 /1.086*SFD

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⇒ Iv,obs. = Iv,em.(1− e−τ ) /τ

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T ∝ v−2.15

CWRU, February 2009



Foregrounds: DustForegrounds: 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

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

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Ttherm. ∝ v +1.3

Tspin ∝ v−2.85

CWRU, February 2009



Foregrounds: SynchrotronForegrounds: 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.)

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.)

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−2.3 < β < −3.05

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T ∝ v β

CWRU, February 2009

Template FittingTemplate Fitting

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P =

P1

P2

P3

P4

P5

⎛

⎝

⎜ ⎜ ⎜ ⎜ ⎜ ⎜

⎞

⎠

⎟ ⎟ ⎟ ⎟ ⎟ ⎟

Solve Matrix Equation: Pa = w

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Pi =

f1,i d1,i s1,i

f2,i d2,i s2,i

. . .

. . .

. . .

fN p ,i dN p ,i sN p ,i

⎛

⎝

⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜

⎞

⎠

⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟€

⇑

€

w =

T1,1 − c1

T2,1 − c2

.

.

.

T1,2 − c1

.

.

.

TN p ,5 − cN p

⎛

⎝

⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜

⎞

⎠

⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟

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a =

a f ,1

ad ,1

as,1

a f ,2

ad ,2

as,2

.

.

.

as,5

⎛

⎝

⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜ ⎜

⎞

⎠

⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟

CWRU, February 2009

Template Fitting

P ≠square P ≠ linearly independent rows

Minimise

€

χ 2 =P

σa −

w

σ by solving for pseudoinverse P+

€

a = P+w€

} P ≠invertible

CWRU, February 2009

3-template fit3-template fit Multi-linear regression of free-free, dust and synchrotron templates Multi-linear regression of free-free, dust and synchrotron templates

Nside=64

Beam Width=3

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} Determined by Gibbs Sampling

Residual Map r=Pa-w

(Gibbs) (ILC)

Unwanted sources

CWRU, February 2009

3-template fit3-template fit Remove point sources, re-fit … Remove point sources, re-fit …

(K-Band) (Ka-Band)

(Q-Band)

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χ red.2 =

χ 2

v, v = N p − Na

χ red.2 = 7.85 (Gibbs), 11.05 (ILC)

CWRU, February 2009

3-template fit3-template fitIntroduce 2:Introduce 2:

(K-Band) (Ka-Band) (Q-Band)

€

2 =1

N p

ζ i, j2 =

1

N p

x i, j − xi( )

2

σ i, j2

j=1

N p

∑j=1

N p

∑

2K = 5.54 (6.59), 2

Ka = 0.88 (1.45), 2Q = 1.08 (2.12) [Full-Sky]

2>1 significant

2K = 14.69 (16.59), 2

Ka = 1.65 (2.42), 2Q = 1.60 (2.84) [< 50]

CWRU, February 2009

Using ratios of elements of a

Using ratios of elements of a

3-template fit

€

Iv ∝ v β

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+1.14 (+1.23) < β dust < − 2.93 (−2.99)

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β ff = −1.93 (−1.80)

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βsync = −2.93 (−3.13)

CWRU, February 2009

Correlation Matrix: Correlation Matrix:

3-template fit

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φX,r =x i − x[ ] ri − r[ ]

x i − x[ ]2

ri − r[ ]2

Haze is correlated with Synchrotron Emission

CWRU, February 2009

Haze is statistically significant < 50 around GC Haze is correlated with Synchrotron emission

Exotic component (e.g. Dark Matter) ??? If so, would expect β<50° ≠ β>50°k

Allow for spatial variation in βsync. by using multiple templates…

Haze is statistically significant < 50 around GC Haze is correlated with Synchrotron emission

Exotic component (e.g. Dark Matter) ??? If so, would expect β<50° ≠ β>50°k

Allow for spatial variation in βsync. by using multiple templates…

3-template fit

= 50

CWRU, February 2009

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min . = 46.5o

χ red.,min.2 = 9.173 (17%)

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min . = 48.5o

χ red.,min.2 = 6.379 (16%)

Minimise χ2red. w.r.t. using two Synchrotron templates Minimise χ2red. w.r.t. using two Synchrotron templates

4-template fit

(ILC)(Gibbs)

CWRU, February 2009

4-template fit4-template fit(K-Band) (Ka-Band) (Q-Band)

∆2K(%)=20.0 (18.7), ∆ 2

Ka(%) =7.7 (6.8), ∆2Q(%)=6.3 (4.9) [FS]

∆2K(%)=46.0(45.5), ∆2

Ka(%) =24.8(24.9), ∆2Q(%)=25.2(22.0) [<50]

CWRU, February 2009

Using ratios of elements of a for synchrotron components

Using ratios of elements of a for synchrotron components

4-template fit

€

Iv ∝ v β

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β>50o = −2.89 (−3.11)

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β<50o = −2.99 (−3.13)

CWRU, February 2009

Dark MatterDark 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)

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-state e+/- 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

Ingredients for DM contribution: Calculate e+/- injection spectrum for WIMPs (i.e. per annihilation) Calculate steady-state e+/- 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

Neutralino DM (LSP): Neutralino DM (LSP):

Neutralino ModelsNeutralino Models

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χ10

~

= N11 B0~

+ N12 W30

~

+ N13 H10

~

+ N14 H20

~

4 Benchmark models:

€

mχ = 50 GeV, B(χχ → bb) = 0.96, B(χχ → τ +τ −) = 0.04

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mχ =150 GeV, B(χχ → bb) = 0.96, B(χχ → τ +τ −) = 0.04

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mχ = 600 GeV, B(χχ → bb) = 0.87, B(χχ → τ +τ −) = 0.13

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mχ =150 GeV, B(χχ → W +W −) = 0.58, B(χχ → Z 0Z 0) = 0.42

(Gaugino)

(Gaugino)

(Higgsino)

(Mixed)

CWRU, February 2009

Solve diffusion-loss equation: Solve diffusion-loss equation:

Steady-State e+/- distributionSteady-State e+/- distribution

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Q(ε,r)∝σv

mχ2 ρ(r)2 dφ

dε

Charged particles undergo random walk Cylindrical (uniform) diffusion zone of depth 2L Assume no re-acceleration of solar modulation

CWRU, February 2009


CWRU, February 2009


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K = K0 = 9 ×1027cm s-1,τ E =1016s, L =10kpc, (α ,β ,γ) = (1,3,1), rs = 20kpc, ρ s = 5.6 ×10−25g cm-3

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mχ = 50 GeV, B(χχ → e+e−) =1

σv = 2 ×10−26cm3s−1

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mχ = 50 GeV, B(χχ → bb) = 0.96,

B(χχ → τ +τ −) = 0.04, σv = 2.7 ×10−26cm3s−1

CWRU, February 2009

Synchrotron Radiation SpectrumSynchrotron Radiation Spectrum e+/- accelerated by galactic B-field, confined to helical paths Lorentz factor =E/me

isotropic distribution of pitch angles

CWRU, February 2009

Synchrotron Radiation SpectrumSynchrotron Radiation Spectrum

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B =10μG, vobs. = 22.8 GHz (K - band)

Only e+/- with 2>/B (i.e. x<1, E>12GeV) contribute significantly

CWRU, February 2009

Synchrotron Radiation SpectrumSynchrotron Radiation Spectrum

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mχ = 50 GeV, B(χχ → bb) = 0.96,

B(χχ → τ +τ −) = 0.04, σv = 2.7 ×10−26cm3s−1

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mχ = 50 GeV, B(χχ → e+e−) =1

σv = 2 ×10−26cm3s−1

CWRU, February 2009

DM Synchrotron FluxDM Synchrotron Flux

Synchrotron Power for individual e+/-

Integrate along l.o.s. with inclination wrt GC

CWRU, February 2009

Results for DM Synchrotron FluxResults for DM Synchrotron Flux

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K0 =1028cm2s−1,α = 0.33,τ E = 2 ×1015s, f sync. = 0.25,B =10μG,L = 3kpc

Significant Boost Factors (BF) required for Haze!

CWRU, February 2009

SummarySummary 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.

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.

can the wmap haze really be a signature of annihilating neutralino dark matter?

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