Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measuring the Mach number of the Universe via the Sunyaev-Zeldovich
  effect   We introduce a new statistic to measure more accurately the cosmic sound
speed of clusters of galaxies at different redshifts. This statistic is
evaluated by cross-correlating cosmic microwave background (CMB) fluctuations
caused by the Sunyaev-Zel'dovich effect from observed clusters of galaxies with
their redshifts. When clusters are distributed in redshift bins of narrow
width, one could measure the mean squared cluster peculiar velocity with an
error \sigma_{C_S^2}\lsim (300{\rm km/s})^2. This can be done around z>0.3 with
clusters of flux above 200 mJy which will be detected by PLANCK, coupled with
high resolution microwave images to eliminate the cosmological part of the CMB
fluctuations. The latter can be achieved with observations by the planned ALMA
array or the NSF South Pole telescope and other surveys. By measuring the
cosmic sound speed and the bulk flow in, e.g., 4 spheres of ~ 100h^{-1}Mpc at
z=0.3, we could have a direct measurement of the matter density
0.21<\Omega_m<0.47 at 95 % confidence level.

36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th