Slides of 5 lectures at XV Brazilian School on Cosmology and ...

Equivalent “equ<strong>at</strong>ion <strong>of</strong> st<strong>at</strong>e”?110.50z1 2 3 4 5 60.50z1 2 3 4 5 6–0.5–0.5wL–1–1.5w L=“ ” −123 (1 + z) dD d2 DdzΩ M0(1 + z) 3 H 2 0“dDdzdz 2 + 1” 2− 1wL–1–1.5(i)–2(ii)–2A formal “dark energy equ<strong>at</strong>ion <strong>of</strong> st<strong>at</strong>e” w L(z) for the best-fit TS model, f v0 = 0.76,calcul<strong>at</strong>ed directly from r w (z): (i) Ω M0= 0.33; (ii) Ω M0= 0.279.Description by a “dark energy equ<strong>at</strong>ion <strong>of</strong> st<strong>at</strong>e” makesno sense when there’s no physics behind it; but averagevalue w L ≃ −1 for z < 0.7 makes empirical sense.15th <strong>Brazilian</strong> <strong>School</strong> on Cosmology and Gravit<strong>at</strong>ion, August 2012 – p.95/143