The Euclid project

Cristobal Padilla

The Euclid group at IFAE is lead by Cristobal Padilla, who is the Project Manger of the NISP-FWA and coordinates the group of engineers and technicians to fulfill the Institute responsibilities in Euclid. Some of the postdocs and students in the Cosmology group also help, specially in the preparation of the data and usage of PAU for Euclid science.

Introduction

Euclid is a mission for the European Space Agency (ESA) Cosmic Vision (CV) 2015-25 programme to explore how the Universe evolved over the past 10 billion years to address questions related to fundamental physics and cosmology on the nature and properties of dark energy, dark matter and gravity, as well as on the physics of the early universe and the initial conditions which seed the formation of cosmic structure.

Euclid Goals

To accomplish its goals, Euclid will carry out a wide survey of 15,000 deg2 of the sky free of contamination by light from the Milky Way and the Solar System and a 40 deg2 deep survey to measure the high-redshift universe. The complete survey represents hundreds of thousands of images and several tens of Petabytes of data. Euclid will observe about 10 billion sources out of which more than one billion will be used for weak lensing. Several tens of million galaxy redshifts will be also measured and used for galaxy clustering. With these images Euclid will probe the expansion history of the Universe and the evolution of cosmic structures by measuring the modification of shapes of galaxies induced by gravitational lensing effects of dark matter and the 3-dimension distribution of structures from spectroscopic redshifts of galaxies and clusters of galaxies. Euclid data will provide improvement factors of ~30 in the measurement of the neutrino mass and up to ~400 in the uncertainty of the parameters of the cosmology state equation and will leave legacy catalogs in may areas of galaxy science with exquisite imaging quality and superb Near Infrared Spectroscopy.

Figure 1: Artist View of the Euclid satellite (Copyright ESA).

Euclid Instruments

IFAE is responsible for the design and manufacturing of Euclid's NISP Filter Wheel Assembly

The Satellite will be equipped with a 1.2 m diameter Silicon Carbide (SIC) mirror telescope made by Airbus Defense and Space feeding 2 instruments, VIS and NISP, built by the Euclid Consortium. These instruments are a high quality panoramic visible imager (VIS), a near infrared 3-filter photometer (NISP-P) and a slitless spectrograph (NISP-S). The IFAE is responsible for the design and manufacturing of the NISP Filter Wheel Assembly (NISP-FWA), a device that allows the NISP instrument to select the optical filter used for the images it takes.

IFAE contribution in 2017

During 2017, the first model of the NISP-FWA containing optical elements has been built and tested. That implied the commissioning of all the Ground Segment Equipment and procedures that will be used to assemble the Flight model, including the Cryostat specially designed and manufactured for this project. After the gluing of the metal mounts to the filters, they where thermal cycled and then assembled to the Filter Wheel and the Criomechanism. The complete wheel was installed inside the cryostat to perform optical tests. Finally, the vibration qualification tests where successfully completed for the FWA. All procedures have been exercised and improvements are being implemented before assembling the Optical Qualification model and the Flight Model, that should be done during 2018.