PRIMA: PRIMAger, a far-infrared hyperspectral and polarimetric instrument

The PRobe far-Infrared Mission for Astrophysics (PRIMA) is a proposed infrared observatory for the next decade, with a 1.8\,m telescope actively cooled to 4.5\,K. On board, an infrared camera, PRIMAger, equipped with ultra-sensitive kinetic inductance detector (KID) arrays, will provide observers with coverage of mid-infrared to far-infrared wavelengths from 24 to 261\,$\mu$m. PRIMAger will offer two imaging modes: the Hyperspectral mode will cover the 24-84\,$\mu$m wavelength range with a spectral resolution R$\approx$10, while the Polarimetric mode will provide polarimetric imaging in 4 broad bands, from 80 to 261\,$\mu$m. These observational capabilities have been tailored to answer fundamental astrophysical questions such as black hole and star-formation co-evolution in galaxies, the evolution of small dust grains over a wide range of redshifts, and the effects of interstellar magnetic fields in various environments, as well as to open a vast discovery space with versatile photometric and polarimetric capabilities. PRIMAger is being developed by an international collaboration bringing together French institutes (Laboratoire d’Astrophysique de Marseille and CEA) through the Centre National d’Etudes Spatiales (CNES, France), the Netherlands Institute for Space Reseach (SRON, Netherlands), and the Cardiff University (UK) in Europe, as well as the Jet Propulsion Laboratory (JPL) and Goddard Space Flight Center (GSFC) in the USA.