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Meaning of deceleration parameter flat model q 0 tells you if the Universe is accelerating in its global expansion rate, or decelerating. Flat, matter dominated q0=1/2 Empty Universe q0=0 Flat, radiation dominated q0=1 Flat, Cosmological Constant dominated q0=-1
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Equation of State Revisited
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Distance as a function of redshift
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Exact Distance Solutions for open/closed & mixed models
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Integrating functions Use trapezoid rule f(x) x1 x2 x1x1+ x f(x1)f(x1+ x) Area x(f(x1+ x)+ f(x1))/2
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Trial numerical integration
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Angular Size Distance How big does an object look as a function of redshift Proper Motion Distance Apparent Angular velocity as a function of redshift Luminosity Distance How bright does an object appear as a function of redshift
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Cosmic Chronology How old is an object as a function of redshift Volume Test How does the Volume per dz change as a function of z Structure Test How does structure evolve relative to a model Density Test Measure local density of Matter
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Luminosity Distance – GR + Homogenous Isotropic Universe for a monochromatic source (defined as inverse-square law) the flux an observer sees of an object at redshift z Brightness of object depends exclusively on what is in the Universe How much and its equation of state.
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The Deceleration Parameter Valid for all models Mattig (1958) provides exact solution for matter only Universes
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Distance Modulus Fractional distance change ½(mag change) e.g. 0.1mag difference is 5% distance difference
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Angular Size Distance
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Attempts to fit/understand models: 1920-1995 Number counts of Galaxies – Hubble,Yoshii/Peterson Angular Size Distances - distant radio cores Kellerman Loitering Universes with z=2 Quasars Luminosity Distance with Brightest Cluster Galaxies
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Volume Effects At low z, N z 3, for any non-diverging luminosity function, Hubble observed this to be true, demonstrating that Galaxies uniformly fill the local Universe. He and Humason were unable to reach conclusions on Geometry.
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Angular Size Distance with Compact Radio Sources Kellerman (1993)
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Stepanas & Saha 1995 Result not that constraining
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Excess z~2 QSOs: Loitering Universe Petrosian, V., Saltpeter, E.E. & Szekeres, P. 1967
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Brightest Cluster Galaxies Sandage, Humason & Mayhall 1956 Baum 1957 Peach 1970 Deceleration q 0 >1 But Tinsley 1976 showed Evolution dominates Cosmology
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Methods for Measuring Extra- Galactic Distances Brightest Cluster Galaxies Cepheids Fundamental Plane (D n - /Faber Jackson) Lensing Delay Planetary Nebulae Tully-Fisher Sunyaev-Zeldovich Surface Brightness Fluctuations Supernovae Ia Supernovae II
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