Some ramifications from the choice of clocks in canonical classical and quantum cosmology

To address the problem of time in canonical quantum gravity, one strategy is to use relational observables which results in the use of reference fields or clocks. We explore various ramifications of these clocks in the classical as well as quantum setting. First we show the way the choice of clocks is tied to gauge fixing and gauge invariant variables in the classical cosmological perturbation theory. Second, we discuss the way choice of clocks influences the loop quantization of inflationary spacetimes. Our results point to various subtleties in the use of the reference fields both in the classical and quantum theory. The Euclid mission: current status, results from early observations, and future prospects / 554 The Euclid Mission Max-Planck-Institut für Astronomie The ESA Euclid mission will conduct an extragalactic survey over about 14 000 deg2 of extragalactic sky. The two instruments onboard, VIS and the Near-Infrared Spectrometer and Photometer (NISP), will provide high-resolution optical imaging, as well as near-infrared imaging and spectroscopy over the survey footprint. In addition to accurate weak lensing and clustering measurements that probe structure formation over half of the age of the Universe, its primary probes for cosmology, these exquisite data will enable a wide range of legacy science. In this talk I will present an overview of the Euclid mission, provide an update on the current status of the mission, present results from the Early Release Observations and discuss legacy science within Euclid.