Spectroscopic Cosmological Surveys in the Far-IR

¹ Istituto di Fisica dello Spazio interplanetario - INAF, Via Fosso del Cavaliere 100, 00133 Roma, Italy
² Osservatorio Astronomico di Bologna - INAF, Via Ranzani 1, 40127, Bologna, Italy
³ Osservatorio Astronomico di Padova - INAF, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
⁴ Dipartimento di Astronomia - Universitá di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
⁵ University of Cardiff - School of Physics and Astronomy, 5 The Parade, Cardiff CF24 3YB, United Kingdom
⁶ Dipartimento di Astronomia - Universitá di Bologna - INAF, Via Ranzani 1, 40127, Bologna, Italy
⁷ Astronomy Division, University of California, Los Angeles, CA 90095-1547, USA

Abstract

We show the feasibility of spectroscopic cosmological surveys with the SAFARI instrument onboard of SPICA. The work is done through simulations that make use of both empirical methods, i.e. the use of observed luminosity functions and theoretical models for galaxy formation and evolution. The relations assumed between the line emission to trace AGN and star formation activity have been derived from the observations of local samples of galaxies. The results converge to indicate the use of blind spectroscopy with the SAFARI FTS at various resolutions to study galaxy evolution from the local to the distant (z~3) Universe.

Specifically, two different and independent galaxy evolution models predict about 7-10 sources to be spectroscopically detected in more than one line in a 2’× 2’ SAFARI field of view, down to the expected flux limits of SAFARI, with about 20% of sources to be detected at z>2. SPICA-SAFARI will be therefore excellent at detecting high-z sources and at assessing in a direct way their nature (e.g whether mainly AGN or Star Formation powered) thanks to blind spectroscopy.