Hydrodynamical simulations of the Sunyaev–Zel'dovich effect |
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Authors: | Antonio C. da Silva Domingos Barbosa rew R. Liddle Peter A. Thomas |
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Affiliation: | Astrophysics Group, The Blackett Laboratory, Imperial College, London SW7 2BW;Astronomy Centre, University of Sussex, Brighton BN1 9QJ |
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Abstract: | With detections of the Sunyaev–Zel'dovich (SZ) effect induced by galaxy clusters becoming routine, it is crucial to establish accurate theoretical predictions. We use a hydrodynamical N -body code to generate simulated maps, of size 1 deg2, of the thermal SZ effect. This is done for three different cosmologies: the currently favoured low-density model with a cosmological constant, a critical-density model and a low-density open model. We stack simulation boxes corresponding to different redshifts in order to include contributions to the Compton y -parameter out to the highest necessary redshifts. Our main results are as follows. (i) The mean y -distortion is around 4×10−6 for low-density cosmologies, and 1×10−6 for critical density. These are below current limits, but not by a wide margin in the former case. (ii) In low-density cosmologies, the mean y -distortion is contributed across a broad range of redshifts, with the bulk coming from z ≲2 and a tail out to z ∼5. For critical-density models, most of the contribution comes from z <1. (iii) The number of SZ sources above a given y depends strongly on instrument resolution. For a 1-arcmin beam, there are around 0.1 sources per deg2 with y >10−5 in a critical-density Universe, and around 8 such sources per deg2 in low-density models. Low-density models with and without a cosmological constant give very similar results. (iv) We estimate that the Planck satellite will be able to see of order 25 000 SZ sources if the Universe has a low density, or around 10 000 if it has critical density. |
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Keywords: | galaxies: clusters: general cosmic microwave background |
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