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تسجيل مستخدم جديدVelocity-Density Correlations from the cosmicflows-3 Distance Catalog and the 2MASS Redshift Survey
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Adi Nusser
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The peculiar velocity of a mass tracer is on average aligned with the dipole modulation of the surrounding mass density field. We present a first measurement of the correlation between radial peculiar velocities of objects in the cosmicflows-3 catalog and the dipole moment of the 2MRS galaxy distribution in concentric spherical shells centered on these objects. Limiting the analysis to cosmicflows-3 objects with distances of $100 rm Mpc h^{-1}$, the correlation function is detected at a confidence level $> 4sigma$. The measurement is found consistent with the standard $Lambda$CDM model at $< 1.7sigma$ level. We formally derive the constraints $0.32<Omega^{0.55}sigma_8<0.48$ ($68% $ confidence level) or equivalently $0.34<Omega^{0.55}/b<0.52$, where $b$ is the galaxy bias factor. Deeper and improved peculiar velocity catalogs will substantially reduce the uncertainties, allowing tighter constraints from this type of correlations.
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