Volume 378, Number 3, November II 2001
|729 - 734
|15 November 2001
The cold local Hubble flow as a signature of dark energy
Institute of Astronomy, St. Petersburg State University, Staryj Peterhoff, 198504 St. Petersburg, Russia
2 Isaac Newton Institute of Chile, Saint-Petersburg Branch, Russia
3 Tuorla Observatory, University of Turku, 21500 Piikkiö, Finland
4 Division of Astronomy, University of Oulu, 90014 Finland
5 Sternberg Astronomical Institute, Moscow University, 119899 Moscow, Russia
Corresponding author: P. Teerikorpi, firstname.lastname@example.org
Accepted: 6 September 2001
The Local Group environment at 1-10 Mpc expands linearly and smoothly, as if ruled by uniform matter, while observations show on the same scales the very lumpy local galaxy universe. This enigma in cosmology has also been demonstrated by high-resolution N-body CDM simulations. We suggest that the homogeneous dark energy component, revealed by SNIa observations, may resolve the problem of the local cold Hubble flow within the highly non-uniform environment. Linear density perturbations on a homogeneous background with the equation of state are decaying for . Exact non-linear Einstein's equations for a spherically symmetric matter concentration, show that there is a zero-mass surface where the positive mass of the local cloud is compensated by the negative dark energy mass, and beyond this surface dark energy dominates dynamically. In such regions the velocity dispersion is adiabatically cooling, and this may explain why the Hubble law starts on the outskirts of the Local Group, with the same H0 as globally and with a remarkably small velocity dispersion.
Key words: dark matter / cosmological parameters / Local Group
© ESO, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.