Max Tegmark's cosmology library: sz
The expected 1-sigma errors of peculiar velocity
measurements for the XBACs cluster
sample (Ebeling 1993) for our fiducial standard cosmological model
Omega_b=0.06) and a beam size of 8'
and 4', respectively. The assumed optical depths and core radii
are as in Fig 5. An axisymmetric optimal filter was applied
using a beta-model for the cluster gas distribution.
The pixel noise is fixed and corresponds to 7 micro-Kelvin
in the 4' beam.
300k compressed version of the paper, including all the figures
(unpack it with "gunzip sz.ps.gz").
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other research of mine.
USING THE KINEMATIC SUNYAEV-ZELDOVICH EFFECT TO
DETERMINE THE PECULIAR VELOCITIES OF CLUSTERS OF GALAXIES
Authors: Martin Haehnelt & Max Tegmark
We have investigated the possibility of inferring peculiar velocities
for clusters of galaxies from the Doppler shift of scattered
cosmic microwave background (CMB) photons. We find that if the core
radius of the gas distribution or the beam size of the instrument is
larger than 3-7 arcminutes, then the maximum attainable
signal-to-noise ratio is determined by confusion with
primary fluctuations. For smaller angular scales, ``cosmic confusion''
is less important and instrumental noise and/or foreground
emission will be the limiting factor. For a cluster with the optical
depth of the Coma cluster and for an optimal filtering technique,
typical one-sigma errors span the wide range from 400 to 1600 km/s,
depending on the cosmological model, the resolution of the instrument
and the core radius of the cluster. The results have important
implications for the design of future high-resolution surveys of the CMB.
Individual peculiar velocities will be measurable only for a few
fast moving clusters at intermediate redshift unless cosmic
fluctuations are smaller than most standard cosmological scenarios
predict. However, a reliable measurement of bulk velocities of
ensembles of X-ray bright clusters will be possible on very large
scales (100-500 Mpc/h).
Preprint MPA 883. Accepted for publication in MNRAS.
This site also contains the latest version of another paper of mine
that recurs in the text;
Tegmark & Efstathiou 1995 ("T95").
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This page was last modified July 1, 1998.