Norwegian Participation in Euclid: Implementation phase

The Euclid project is now well advanced, with launch planned for 2020. We participate in many parts of the project, including in the leadership through the Norwegian member of the Euclid Consortium Board. By now, 14 Norwegian scientists are members of the Euclid consortium. On contract with the University of Oslo (financed through ESA's PRODEX programme), CMR Prototech constructs and builds two flight hardware mechanical structures for the NISP instrument: NI-SSS, Sidecar Support Structure, the rear part of the Focal Plane Assembly) and NI-SA HP, the hexapod which fixes the NISP instrument in the payload module of the spacecraft. Detailed work is well advanced, for NI-SSS we have delivered one dummy and two Structural and Thermal Models, for NI-SA-HP one dummy has been delivered and one Structural and Thermal Model is presently being machined. Instrument PDR (Preliminary Design Reviw) for the NISP instrument was held in May 2014 and more detailed Subsystem PRDs were held autumn/winter 2014/2015. We participated very actively in these, delivering about 15 documents for each structure. The Subsystem CDRs (Critical Design Review) are scheduled for December 2015. The Norwegian part of the Science Ground Segment, Data Quality Common Tools, are being designed at the University of Oslo in cooperation with groups at the universities of Helsinki and Naples. This is also financed through ESA's PRODEX programme. FInanced through the current Research Council project, we have had a strong position in the Euclid working groups on cosmological theory and cosmological simulations. The work package on cosmological simulations of alternative gravity theories is lad by Prof. David F. Mota, and in connections with that, major breakthroughs have been made, of importance for Euclid, but also generally: An important class of alternative gravity theories consists of theories where one in addition to a tensor field has a scalar field which interacts with matter. This interaction must be in such a way that the effect is shielded where the mass density is high, e.g., in the solar system and also internal in galaxies, so that observational constraints are fulfilled. Observable consequences (through Euiclid) of such theories have been studied "en masse" by our group in several new papers in 2014 and 2015, especially based on new cosmological simulations. A joint meeting of the Euclid cosmological theory and cosmological simulations science working groups was held in Oslo in January 2015, followed by a large international conference.

One of the most outstanding problems in physics and astrophysics today is the existence of dark energy, which is inferred from the apparent accelerated expansion of the universe. Dark energy is believed to comprise about 70% of the energy content of the u niverse today, however, it's nature is largely unknown. The simplest model is to assume that the dark energy is in the form of a cosmological constant. There are, however, good reasons to believe that the nature of the dark energy could be more complicate d than this. Euclid is an M-class mission with a targeted launch in l2019. Its primary objective is to study dark energy, secondary objectives are covering most of cosmology and astrophysics. The main observational targets will be baryonic acoustic oscil lations and weak gravitational lensing measurements. Euclid was selected as the second M-mission in ESA's Cosmic Vision programme on the 4th of October, 2011. This proposal is for the necessary funding of management and coordination of the Norwegian part icipation in Euclid (the direct costs of Norwegian contributions to instruments and science ground segment will be funded by the Norwegian Space Centre), for Norwegian participation in the Euclid Science Working Groups, and for completing a research proje ct in the period 2012-2014 studying the evolution of linear and non-linear structures in the universe in a class of interesting cosmological models called chameleon models. This research project will already give significant constraints on such models whe n compared with existing data, but will especially give interesting forecasts for how Euclid data best can give constraints. Furthermore, the project will build competence in numerical simulations of growth of structure in non-standard cosmological models , something that will be essential in future Euclid research.