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Parameter constraints for flat cosmologies from cosmic microwave background and 2dFGRS power spectra

Percival, Will J. and Sutherland, Will and Peacock, John A. and Baugh, Carlton M. and Bland-Hawthorn, Joss and Bridges, Terry and Cannon, Russell and Cole, Shaun and Colless, Matthew and Collins, Chris and Couch, Warrick and Dalton, Gavin and De Propris, Roberto and Driver, Simon P. and Efstathiou, George and Ellis, Richard S. and Frenk, Carlos S. and Glazebrook, Karl and Jackson, Carole and Lahav, Ofer and Lewis, Ian and Lumsden, Stuart and Maddox, Steve and Moody, Stephen and Norberg, Peder and Peterson, Bruce A. and Taylor, Keith (2002) Parameter constraints for flat cosmologies from cosmic microwave background and 2dFGRS power spectra. Monthly Notices of the Royal Astronomical Society, 337 (3). pp. 1068-1080. ISSN 0035-8711. doi:10.1046/j.1365-8711.2002.06001.x.

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We constrain flat cosmological models with a joint likelihood analysis of a new compilation of data from the cosmic microwave background (CMB) and from the 2dF Galaxy Redshift Survey (2dFGRS). Fitting the CMB alone yields a known degeneracy between the Hubble constant h and the matter density Ωₘ, which arises mainly from preserving the location of the peaks in the angular power spectrum. This ‘horizon-angle degeneracy’ is considered in some detail and is shown to follow the simple relation Ωₘh³.⁴= constant. Adding the 2dFGRS power spectrum constrains Ωₘh and breaks the degeneracy. If tensor anisotropies are assumed to be negligible, we obtain values for the Hubble constant of h= 0.665 ± 0.047, the matter density Ωₘ = 0.313 ± 0.055, and the physical cold dark matter and baryon densities Ωch²= 0.115 ± 0.009, Ωbh²= 0.022 ± 0.002 (standard rms errors). Including a possible tensor component causes very little change to these figures; we set an upper limit to the tensor-to-scalar ratio of r < 0.7 at a 95 per cent confidence level. We then show how these data can be used to constrain the equation of state of the vacuum, and find w < −0.52 at 95 per cent confidence. The preferred cosmological model is thus very well specified, and we discuss the precision with which future CMB data can be predicted, given the model assumptions. The 2dFGRS power-spectrum data and covariance matrix, and the CMB data compilation used here, are available from∼wjp/.

Item Type:Article
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URLURL TypeDescription Paper
Baugh, Carlton M.0000-0002-9935-9755
Bland-Hawthorn, Joss0000-0001-7516-4016
Colless, Matthew0000-0001-9552-8075
Ellis, Richard S.0000-0001-7782-7071
Norberg, Peder0000-0002-5875-0440
Alternate Title:Parameter constraints for flat cosmologies from CMB and 2dFGRS power spectra
Additional Information:© 2002 RAS. Accepted 2002 August 16. Received 2002 August 14; in original form 2002 July 1. The 2dF Galaxy Redshift Survey was made possible through the dedicated efforts of the staff of the Anglo-Australian Observatory, both in creating the 2dF instrument and in supporting it on the telescope.
Subject Keywords:cosmic microwave background, cosmological parameters, large-scale structure of Universe
Issue or Number:3
Record Number:CaltechAUTHORS:20200629-094519270
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Official Citation:Will J. Percival, Will Sutherland, John A. Peacock, Carlton M. Baugh, Joss Bland-Hawthorn, Terry Bridges, Russell Cannon, Shaun Cole, Matthew Colless, Chris Collins, Warrick Couch, Gavin Dalton, Roberto De Propris, Simon P. Driver, George Efstathiou, Richard S. Ellis, Carlos S. Frenk, Karl Glazebrook, Carole Jackson, Ofer Lahav, Ian Lewis, Stuart Lumsden, Steve Maddox, Stephen Moody, Peder Norberg, Bruce A. Peterson, Keith Taylor, (The 2dFGRS Team), Parameter constraints for flat cosmologies from cosmic microwave background and 2dFGRS power spectra, Monthly Notices of the Royal Astronomical Society, Volume 337, Issue 3, December 2002, Pages 1068–1080,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104122
Deposited By: Rebecca Minjarez
Deposited On:30 Jun 2020 16:55
Last Modified:16 Nov 2021 18:28

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