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Concept study for measuring the CO smic D ifferential EX pansion

Concept study for measuring the CO smic D ifferential EX pansion. The Experiment.

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Concept study for measuring the CO smic D ifferential EX pansion

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  1. Concept study for measuring the COsmic Differential EXpansion

  2. The Experiment ”It should be possible to choose between various models of the expanding universe if the deceleration of a given galaxy could be measured. Precise predictions of the expected change in z=dl/l0 for reasonable observing times (say 100 years) is exceedingly small. Nevertheless, the predictions are interesting, since they form part ofthe available theory for the evolution of the universe” Sandage 1962 ApJ 136,319 Sandage predictions: z=0.4, k=+1 dz/dt = -0.73 cm /sec/year k= -1 -0.3 k= 0 -0.59 Steady state +0.92

  3. What’s new • VLT-UVES & Keck HIRES observed hundreds of QSOs at High Res ( 40000), z between 2 and 5, V=16-18 • Exoplanets (HARPS) long term accuracy 1m/s, short term (hours) 0.1m/s (and largely understood) • ELT (100m)

  4. Collaboration: ESO-Cambridge-Geneve-Trieste • About 25 people involved, 5 Work Packages Study Management Experiment Science Case Science Methodology Parallel Science Instrument Concept

  5. cosmic signal te=emission epoch t0=actual epoch

  6. Freedman 2002 from Loeb 1998

  7. Grazian et al 2005

  8. Direct measurement • Bias-free determination of cosmological parameters • Different redshift (CMB, SNIa) • Not dependent from evolutionary effects of sources

  9. Cosmological Variation of the Fine-structure Constant Outstanding projects Terrestrial planets in extra-solar systems Primordial nucleosynthesis, Q-H phase (?)

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