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Unformatted text preview: COSMOLOGY Problem Set 3 April 12, 2010 Problem 1 : Matter Dominated Evolution Consider a Matter Dominated (MD: p = 0, = 0) RobertsonWalkerFriedman cosmological model. a) Find the density parameter as a function of the redshift, ( z ), and its present value . In the limit of high redshift (e.g., z > 1) find ( z ). [10] b) In terms of H and , find the Hubble parameter as a function of redshift, H ( z ). In the limit of high redshift (e.g., z > 1) find H ( z ). [10] c) For < 1, find an analytic expression for the ratio of the present age to the Hubble age, H t , as a function of . How old is this Universe at present if = 0 . 3 (you may assume H = 70 km/s/Mpc)? [10] d) How old would this Universe be at present if = 1? [5] Problem 2 : MD, High Density For a MD, RWF model with = 2 find: [Note: You may assume here that a c/H .] a) The present comoving radial coordinate of the horizon, H ( t ). What fraction of the entire Universe is observable (in principle) at...
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This note was uploaded on 07/28/2011 for the course PHY 880.20 taught by Professor Steigman during the Spring '10 term at Ohio State.
 Spring '10
 STEIGMAN

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