A Milestone to SPICA Extragalactic Surveys: The AKARI NEP Survey

¹ Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Japan
² Institute for Astronomy, University of Hawaii, USA
³ Academia Sinica, Institute of Astronomy and Astrophysics, Taiwan
⁴ Physics section, Faculty of Humanities and Social Sciences, Iwate University, Japan
⁵ Rutherford Appleton Laboratory, UK
⁶ Department of Physics, The Open University, UK
⁷ Department of Physics & Astronomy, FPRD, Seoul National University, Korea
⁸ Department of Physics and Astronomy, UCLA, USA

Abstract

Large area surveys in the infrared wavelengths have revealed a significant evolution of the star formation activity of the universe in the past. The extragalactic sur- vey we have conduced with AKARI towards the north ecliptic pole (NEP) is unique, in terms of a comprehensive wavelength coverage from 2 to 24 micron using all 9 photometric bands of the Infrared Camera (IRC). We demonstrate that this IRC all-band photometry is capable of tracing a steep rise in the flux at the blue side of the polycyclic aromatic hydrocarbon (PAH) 6.2 micron emission feature of infrared luminous galaxies at z < 1. This allows us to estimate redshifts of mid-IR sources and identify `ultra-luminous starburst galaxies', based on mid-IR spectral energy distributions (SEDs). SPICA could inherit this unique capability of AKARI and extend the study to typical galaxy populations at z ~ 2, i.e. a critical period of galaxy formation.