Cosmological Parameters from the Comparison of the 2MASS Gravity Field with Peculiar Velocity Surveys

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dc.creatorPike, R. W.
dc.creatorHudson, Michael J.
dc.date2005-11-01
dc.date.accessioned2026-07-07T06:44:47Z
dc.date.available2026-07-07T06:44:47Z
dc.descriptionWe compare the peculiar velocity field within 65 $h^{-1}$ Mpc predicted from 2MASS photometry and public redshift data to three independent peculiar velocity surveys based on type Ia supernovae, surface brightness fluctuations in ellipticals, and Tully-Fisher distances to spirals. The three peculiar velocity samples are each in good agreement with the predicted velocities and produce consistent results for $β_{K}=Ω\sbr{m}^{0.6}/b_{K}$. Taken together the best fit $β_{K} = 0.49 \pm 0.04$. We explore the effects of morphology on the determination of $β$ by splitting the 2MASS sample into E+S0 and S+Irr density fields and find both samples are equally good tracers of the underlying dark matter distribution, but that early-types are more clustered by a relative factor $b\sbr{E}/b\sbr{S} \sim 1.6$. The density fluctuations of 2MASS galaxies in $8 h^{-1}$ Mpc spheres in the local volume is found to be $σ\sbr{8,K} = 0.9$. From this result and our value of $β_{K}$, we find $σ_8 (Ω\sbr{m}/0.3)^{0.6} = 0.91\pm0.12$. This is in excellent agreement with results from the IRAS redshift surveys, as well as other cosmological probes. Combining the 2MASS and IRAS peculiar velocity results yields $σ_8 (Ω\sbr{m}^/0.3)^{0.6} = 0.85\pm0.05$.
dc.description11 pages, ApJ accepted
dc.identifierhttps://arxiv.org/abs/astro-ph/0511012
dc.identifierhttp://arxiv.org/abs/astro-ph/0511012
dc.identifierAstrophys.J. 635 (2005) 11-21
dc.identifierdoi:10.1086/497359
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/102862
dc.subjectAstrophysics
dc.titleCosmological Parameters from the Comparison of the 2MASS Gravity Field with Peculiar Velocity Surveys
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