[PPT] - The Extragalactic Radio Background from Dark Matter Annihilation PowerPoint Presentation

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The Extragalactic Radio Background from Dark Matter Annihilation and the ARCADE-2 Excess

Ke Fang

JSI Fellow University of Maryland & NASA GSFC TeVPA - Oct 27, 2015

KF & Linden PRD.91.083501, 1412.7545 KF & Linden submitted to PRD, 1506.05807

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Fixsen et al, ApJ, 0901.0555 Kogut et al, ApJ, 734, 4, 2011 Singal et al, MNRAS, 409, 1172, 2010

 

22 MHz - 10 GHz

The ARCADE-2 Excess

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Fixsen et al, ApJ, 0901.0555 Kogut et al, ApJ, 734, 4, 2011 Singal et al, MNRAS, 409, 1172, 2010

 

22 MHz - 10 GHz

The ARCADE-2 Excess

Tarcade = 1.26 ⇣ ν GHz ⌘−2.6 K

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Fixsen et al, ApJ, 0901.0555 Kogut et al, ApJ, 734, 4, 2011 Singal et al, MNRAS, 409, 1172, 2010

 

22 MHz - 10 GHz

The ARCADE-2 Excess

Tsources = 0.23 ⇣ ν GHz ⌘−2.7 K

Tarcade = 1.26 ⇣ ν GHz ⌘−2.6 K

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Fixsen et al, ApJ, 0901.0555 Kogut et al, ApJ, 734, 4, 2011 Singal et al, MNRAS, 409, 1172, 2010

 

22 MHz - 10 GHz

The ARCADE-2 Excess

Tsources = 0.23 ⇣ ν GHz ⌘−2.7 K

Exceeds the isotropic galactic diffuse emission & flux of extragalactic radio sources

Tarcade = 1.26 ⇣ ν GHz ⌘−2.6 K

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3 Fornengo et al, PRL, 107 (2011) 271302 Hooper et al, PRD, 86.103003, 2012

Dark matter YES Dark matter annihilation —> electrons —> diffusive synchrotron emission

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1•104 2•104 3•104 L 0.01 0.10 [L(L+1)CL/2π]1/2 (∆T/T) VLA 4.9 GHz VLA 8.4 GHz ATCA 8.7 GHz

z=[0,1] z=[0,2] z=[5,10]

1 Mpc/h 2 Mpc/h

Planck 857 GHz

Fornengo et al, PRL, 107 (2011) 271302 Hooper et al, PRD, 86.103003, 2012 Holder, ApJ 780 (2014) 112

Dark matter YES Dark matter annihilation —> electrons —> diffusive synchrotron emission Dark matter NO Unusual smoothness of the unresolved radio background —> unlikely from large-scale structure

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1•104 2•104 3•104 L 0.01 0.10 [L(L+1)CL/2π]1/2 (∆T/T) VLA 4.9 GHz VLA 8.4 GHz ATCA 8.7 GHz

z=[0,1] z=[0,2] z=[5,10]

1 Mpc/h 2 Mpc/h

Planck 857 GHz

Holder, ApJ 780 (2014) 112

Anisotropy Constraints

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1•104 2•104 3•104 L 0.01 0.10 [L(L+1)CL/2π]1/2 (∆T/T) VLA 4.9 GHz VLA 8.4 GHz ATCA 8.7 GHz

z=[0,1] z=[0,2] z=[5,10]

1 Mpc/h 2 Mpc/h

Planck 857 GHz

Holder, ApJ 780 (2014) 112

Anisotropy Constraints

mass power spectrum

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1•104 2•104 3•104 L 0.01 0.10 [L(L+1)CL/2π]1/2 (∆T/T) VLA 4.9 GHz VLA 8.4 GHz ATCA 8.7 GHz

z=[0,1] z=[0,2] z=[5,10]

1 Mpc/h 2 Mpc/h

Planck 857 GHz

Holder, ApJ 780 (2014) 112

Anisotropy Constraints

C` ∝ ✓ δT Texcess ◆2 = ✓ δT TCMB TCMB Texcess ◆2

mass power spectrum

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1•104 2•104 3•104 L 0.01 0.10 [L(L+1)CL/2π]1/2 (∆T/T) VLA 4.9 GHz VLA 8.4 GHz ATCA 8.7 GHz

z=[0,1] z=[0,2] z=[5,10]

1 Mpc/h 2 Mpc/h

Planck 857 GHz

Holder, ApJ 780 (2014) 112

Anisotropy Constraints

C` ∝ ✓ δT Texcess ◆2 = ✓ δT TCMB TCMB Texcess ◆2

mass power spectrum CMB observation

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1•104 2•104 3•104 L 0.01 0.10 [L(L+1)CL/2π]1/2 (∆T/T) VLA 4.9 GHz VLA 8.4 GHz ATCA 8.7 GHz

z=[0,1] z=[0,2] z=[5,10]

1 Mpc/h 2 Mpc/h

Planck 857 GHz

Holder, ApJ 780 (2014) 112

Anisotropy Constraints

uncertainties in excess temperature above 5 GHz -> requires a consistent computation of intensity & anisotropy

C` ∝ ✓ δT Texcess ◆2 = ✓ δT TCMB TCMB Texcess ◆2

mass power spectrum CMB observation

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Intensity of the Extragalactic DM signals

Ando & Komatsu arXiv: 1301.5901, 0512217 KF & Linden PRD.91.083501, arXiv: 1412.7545

I(Es) = Z dχδ2(z) W[(1 + z)Es, χ]

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Intensity of the Extragalactic DM signals

Ando & Komatsu arXiv: 1301.5901, 0512217 KF & Linden PRD.91.083501, arXiv: 1412.7545

/ hσvi dN

dEs I(Es) = Z dχδ2(z) W[(1 + z)Es, χ]

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Intensity of the Extragalactic DM signals

Ando & Komatsu arXiv: 1301.5901, 0512217 KF & Linden PRD.91.083501, arXiv: 1412.7545

∝

Z dM dn(M, z) dM Z dV ρDM(r, M, z)2

/ hσvi dN

dEs I(Es) = Z dχδ2(z) W[(1 + z)Es, χ]

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Intensity of the Extragalactic DM signals

Ando & Komatsu arXiv: 1301.5901, 0512217 KF & Linden PRD.91.083501, arXiv: 1412.7545

∝

Z dM dn(M, z) dM Z dV ρDM(r, M, z)2

/ hσvi dN

dEs

I(Es) =

Z dχδ2(z) W[(1 + z)Es, χ]

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Intensity of the Extragalactic DM signals

Ando & Komatsu arXiv: 1301.5901, 0512217 KF & Linden PRD.91.083501, arXiv: 1412.7545

∝

Z dM dn(M, z) dM Z dV ρDM(r, M, z)2

/ hσvi dN

dEs

I(Es) =

Z dχδ2(z) W[(1 + z)Es, χ]

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Anisotropy of the Extragalactic DM signals

C`(Es) = 1 I(Es)2 Z dχ χ2 W 2[(1 + z)Es, χ] P2(k, z)

Ando & Komatsu arXiv: 1301.5901, 0512217 KF & Linden PRD.91.083501, arXiv: 1412.7545

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Anisotropy of the Extragalactic DM signals

C`(Es) = 1 I(Es)2 Z dχ χ2 W 2[(1 + z)Es, χ] P2(k, z)

Ando & Komatsu arXiv: 1301.5901, 0512217 KF & Linden PRD.91.083501, arXiv: 1412.7545

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Anisotropy of the Extragalactic DM signals

C`(Es) = 1 I(Es)2 Z dχ χ2 W 2[(1 + z)Es, χ] P2(k, z)

P(k, z) = P1h(k, z) + P2h(k, z)

P1h(k, z) = Z dM dn dM |˜ u(k, M)|2

Ando & Komatsu arXiv: 1301.5901, 0512217 KF & Linden PRD.91.083501, arXiv: 1412.7545

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Substructure Contribution

ρ2

sync(r, M) = ρ2 DM(r, M)

ρB ρB + ρCMB

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Substructure Contribution

ρ2

sync(r, M) = ρ2 DM(r, M)

ρB ρB + ρCMB

1 − fs(r) = 7 × 10−3

✓ ρh(r) ρh(r = 100 kpc) ◆−0.26

Kamionkowski+ PRD 81 043532 (2010)

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Substructure Contribution

ρ2

sync(r, M) = ρ2 DM(r, M)

ρB ρB + ρCMB

1 − fs(r) = 7 × 10−3

✓ ρh(r) ρh(r = 100 kpc) ◆−0.26

Kamionkowski+ PRD 81 043532 (2010)
B(M, r) = B0

✓ M M0 ◆α " 1 + ✓ r rc ◆2#−3βη/2

Bsub = 4µG for M = 1014M

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Results with different DM models

KF & Linden PRD.91.083501, 1412.7545

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A Consistent Picture

KF & Linden PRD.91.083501, 1412.7545

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A Consistent Picture

KF & Linden PRD.91.083501, 1412.7545

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A Consistent Picture - model III

KF & Linden PRD.91.083501, 1412.7545

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KF & Linden submitted to PRD, 1506.05807

Alternative to Substructure - Alfven Re-acceleration in Galaxy Clusters

Image credit: Bonafede et. al. 2014

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KF & Linden submitted to PRD, 1506.05807

Alternative to Substructure - Alfven Re-acceleration in Galaxy Clusters

Image credit: Bonafede et. al. 2014

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KF & Linden submitted to PRD, 1506.05807

Alternative to Substructure - Alfven Re-acceleration in Galaxy Clusters

Image credit: Bonafede et. al. 2014

∂Wk(t) ∂t = −Γ(k)Wk(t) + IA(k, t) ∂f ∂t = 1 p ∂ ∂p  p2Dpp ∂f ∂p + Sp4f

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KF & Linden submitted to PRD, 1506.05807

Alternative to Substructure - Alfven Re-acceleration in Galaxy Clusters

Image credit: Bonafede et. al. 2014

∂Wk(t)

∂t = −Γ(k)Wk(t) + IA(k, t) ∂f ∂t = 1 p ∂ ∂p  p2Dpp ∂f ∂p + Sp4f

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Conclusion

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Conclusion

Synchrotron emission from dark matter annihilations

could explain the ARCADE-2 excess while being consistent with anisotropy limits

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Conclusion

Synchrotron emission from dark matter annihilations

could explain the ARCADE-2 excess while being consistent with anisotropy limits

Need contribution from extended substructure & B-field

OR Alfvenic re-acceleration

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Conclusion

Synchrotron emission from dark matter annihilations

could explain the ARCADE-2 excess while being consistent with anisotropy limits

Need contribution from extended substructure & B-field

OR Alfvenic re-acceleration

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Conclusion

Synchrotron emission from dark matter annihilations

could explain the ARCADE-2 excess while being consistent with anisotropy limits

Need contribution from extended substructure & B-field

OR Alfvenic re-acceleration

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Conclusion

Synchrotron emission from dark matter annihilations

could explain the ARCADE-2 excess while being consistent with anisotropy limits

Need contribution from extended substructure & B-field