Investigating Galaxy Evolution with FIR Observatories: Herschel and Beyond: Herschel and Beyond

The far infrared and submillimetre spectral region is critical to the characterisation of the obscured Universe, both locally and at high redshift. The Herschel Space Observatory is the fourth cornerstone mission in the European Space Agency (ESA) science programme. Herschel is equipped with a passively cooled 3.5-m diameter Cassegrain telescope and three scientific instruments - HIFI, PACS and SPIRE - which together are carrying out sensitive imaging and spectroscopy at wavelengths between 55 and 671 μm. This paper summarises the design and scientific capabilities of Herschel and its instruments for studying galaxy evolution over cosmic time, and reviews some of its early results. For a comprehensive understanding of the formation of the physics of the ISM in distant galaxies, and the relationship between AGN and their host galaxies, future space-borne observations will be needed with improved sensitivity and angular resolution in the far infrared. SPICA will be the next step in this development, with a great advance over Herschel in sensitivity and spectroscopic power. In the longer term, a far infrared space interferometer will allow us to study the high-redshift Universe with the same capabilities that we currently have for the local Universe