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          Institute: MPI für Astrophysik     Collection: Cosmology     Display Documents

ID: 10723.0, MPI für Astrophysik / Cosmology
Non-Gaussian cosmic microwave background temperature fluctuations from peculiar velocities of clusters
Authors:Yoshida, N.; Sheth, R. K.; Diaferio, A.
Date of Publication (YYYY-MM-DD):2002
Title of Journal:Monthly Notices of the Royal Astronomical Society
Journal Abbrev.:Mon. Not. Roy. Astron. Soc.
Issue / Number:2
Start Page:669
End Page:677
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:We use numerical simulations of a (480 Mpc h(-1))(3) volume to show that the distribution of peak heights in maps of the temperature fluctuations from the kinematic and thermal Sunyaev-Zeldovich (SZ) effects will be highly non-Gaussian, and very different from the peak-height distribution of a Gaussian random field. We then show that it is a good approximation to assume that each peak in either SZ effect is associated with one and only one dark matter halo. This allows us to use our knowledge of the properties of haloes to estimate the peak- height distributions. At fixed optical depth, the distribution of peak heights resulting from the kinematic effect is Gaussian, with a width that is approximately proportional to the optical depth; the non-Gaussianity comes from summing over a range of optical depths. The optical depth is an increasing function of halo mass and the distribution of halo speeds is Gaussian, with a dispersion that is approximately independent of halo mass. This means that observations of the kinematic effect can be used to put constraints on how the abundance of massive clusters evolves, and on the evolution of cluster velocities. The non-Gaussianity of the thermal effect, on the other hand, comes primarily from the fact that, on average, the effect is larger in more massive haloes, and the distribution of halo masses is highly non-Gaussian. We also show that because haloes of the same mass may have a range of density and velocity dispersion profiles, the relation between halo mass and the amplitude of the thermal effect is not deterministic, but has some scatter.
Free Keywords:gravitation; methods : N-body simulations; galaxies : clusters : general; cosmic microwave background; large-scale structure of Universe
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astrophysik/Planck Satellite Group
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