On the Sunyaev-Zel'dovich effect from dark matter annihilation or decay in galaxy clusters
- Dipartimento di Fisica Teorica, Università di Torino and INFN, via Giuria 1, 10125 Torino (Italy)
- LAPTH, UMR 5108, 9 chemin de Bellevue - BP 110, 74941 Annecy-Le-Vieux (France)
We revisit the prospects for detecting the Sunyaev Zel'dovich (SZ) effect induced by dark matter (DM) annihilation or decay. We show that with standard (or even extreme) assumptions for DM properties, the optical depth associated with relativistic electrons injected from DM annihilation or decay is much smaller than that associated with thermal electrons, when averaged over the angular resolution of current and future experiments. For example, we find: τ{sub DM} ∼ 10{sup −9}−10{sup −5} (depending on the assumptions) for m{sub χ} = 1 GeV and a density profile ρ∝r{sup −1} for a template cluster located at 50 Mpc and observed within an angular resolution of 10'', compared to τ{sub th} ∼ 10{sup −3}−10{sup −2}. This, together with a full spectral analysis, enables us to demonstrate that, for a template cluster with generic properties, the SZ effect due to DM annihilation or decay is far below the sensitivity of the Planck satellite. This is at variance with previous claims regarding heavier annihilating DM particles. Should DM be made of lighter particles, the current constraints from 511 keV observations on the annihilation cross section or decay rate still prevent a detectable SZ effect. Finally, we show that spatial diffusion sets a core of a few kpc in the electron distribution, even for very cuspy DM profiles, such that improving the angular resolution of the instrument, eg with ALMA, does not necessarily improve the detection potential. We provide useful analytical formulæ parameterized in terms of the DM mass, decay rate or annihilation cross section and DM halo features, that allow quick estimates of the SZ effect induced by any given candidate and any DM halo profile.
- OSTI ID:
- 22272971
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2010, Issue 02; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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