PRISM (Polarized Radiation Imaging and Spectroscopy Mission): an extended white paper

Abstract

PRISM (Polarized Radiation Imaging and Spectroscopy Mission) was proposed to ESA in May 2013as a large-class mission for investigating within the framework of the ESA Cosmic Visionprogram a set of important scientific questions that require high resolution, high sensitivity, full-skyobservations of the sky emissionat wavelengths ranging from millimeter-wave to the far-infrared.PRISM's main objective is to explore the distant universe, probing cosmichistory from very early times until now as well as the structures, distribution ofmatter, and velocity flows throughout our Hubble volume. PRISM willsurvey the full sky in a large number of frequency bands in bothintensity and polarization and will measure the absolute spectrum of sky emission more thanthree orders of magnitude better than COBE FIRAS. The data obtained will allow usto precisely measure the absolute sky brightness and polarization of all the components of thesky emission in the observed frequency range,separating the primordial and extragalactic components cleanly from the galactic and zodiacal light emissions.The aim of this Extended White Paper is to provide a more detailed overview of the highlightsof the new science that will be made possible by PRISM, which include: (1) the ultimategalaxy cluster survey using the Sunyaev-Zeldovich (SZ) effect, detecting approximately 106clusters extending to large redshift, including a characterization of the gas temperature ofthe brightest ones (through the relativistic corrections to the classic SZ template) as wellas a peculiar velocity survey using the kinetic SZ effect that comprises our entire Hubblevolume; (2) a detailed characterization of the properties and evolution of dusty galaxies, wherethe most of the star formation in the universe took place, the faintest population of whichconstitute the diffuse CIB (Cosmic Infrared Background); (3) a characterization of the B modes fromprimordial gravity waves generated during inflation and from gravitational lensing, as wellas the ultimate search for primordial non-Gaussianity using CMB polarization, which is lesscontaminated by foregrounds on small scales than the temperature anisotropies; (4) a searchfor distortions from a perfect blackbody spectrum, which include some nearly certain signalsand others that are more speculative but more informative; and (5) a study of the role of themagnetic field in star formation and its interaction with other components of theinterstellar medium of our Galaxy. These are but a few of the highlights presented herealong with a description of the proposed instrument.