Measuring the Mach number of the Universe via the Sunyaev-Zeldovich effect. F. Atrio–Barandela 1

• Main Authors: A. Kashlinsky, J. P. Mücket
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2003
• Subjects: Subject headings; Cosmic Microwave Background. Cosmology; theory. Cosmology; South Pole; South pole
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.315.5813; http://arxiv.org/pdf/astro-ph/0312394v1.pdf

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 σC2 S 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−1Mpc at z = 0.3, we could have a direct measurement of the matter density 0.21 < Ωm < 0.47 at 95 % confidence level. ∼(300km/s) 2. This can be done around z> 0.3 with