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Local Group Dynamics

Published online by Cambridge University Press:  25 May 2016

D. Lynden-Bell*
Affiliation:
Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge. CB3 0HA UK

Abstract

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The distance from the Local Group to the ‘sphere’ of small galaxies that no longer expand with the Universe determines the time since the Big Bang, t x M1/2, where M is the mass of the Local Group. Adopting Feast's new distance scale, this distance is found to be 1.35 ± 0.1 Mpc. The velocity of approach and the distance to M31 give a different combination of t and M, thus both can be deduced. We find the time since the Big Bang and The importance of accurate distances for such results is stressed. If all distances are revised by a factor λ then both t and M change by that factor.

Type
Part 1: Setting the Scene
Copyright
Copyright © Astronomical Society of the Pacific 1999 

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