Thesis Topic: Towards a direct measurement of the expansion history of the Universe


Thesis Supervisor: Luca Pasquini
Co-supervisor: Jochen Liske




The European Extremeley Large Telescope (E-ELT) is the future flagship facility of European ground-based optical and infrared astronomy. When completed in 2024 it will be the largest and most advanced telescope ever built.

The E-ELT will allow us, for the first time, to perform a direct and dynamical measurement of the expansion history of the Universe. The evolution of the expansion rate causes the redshifts of distant objects to change slowly with time, and this tiny effect can be measured by comparing high resolution spectra of the intergalactic medium (the Lyα forest) taken at different epochs. This experiment is unique among all cosmological observations, and it will provide the most direct evidence for or against the existence of accelerated expansion possible.

This ambitious project will require advanced instrumentation, with capabilities of measuring velocity shifts significantly beyond the current state of the art (HARPS). Much can be done already now towards this goal. The aim of this thesis project will be to understand, through proper simulations, the subtle astrophysical and technical effects influencing these high-precision observations, from QSO variability to detector systematics. This will lead to the development of an optimal technique to extract the cosmological signal from the data. This work will be used by the candidate to support observing proposals to existing facilities with the aim of verifying the simulations and taking the first observational steps towards a measurement of the expansion history.

The ideal candidate should have a genuine interest in experimental spectroscopy.

References: Liske et al. (2008)

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