We propose a cosmological survey to probe star formation and nuclear activity in galaxies at redshifts of z=2-4 by polycyclic aromatic hydrocarbon (PAH) features using the SPICA mid-infrared instrument (SMI) with a spectral resolution of R=20. We will cover a wavelength range of 20-36 μm that corresponds to z=2-4 for the PAH features (11.3, 7.7, and 6.2 μm). The sensitivity will be 1 X 10-19 W/m2 (5 σ) in case of a reference survey that covers 4 arcmin2 field in a one-hour observation. It corresponds to LIR=2 X 1011 L⊙ at z=3 and will give us more than 10000 galaxies in a 450 hour survey.

ABSTRACT
1. INTRODUCTION
2. THE PAH SURVEY
3. WHAT SPECTRAL RESOLUTION IS REQUIRED?
4. SUMMARY
REFERENCES

• Takehiko Wada(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency)
• Eiichi Egami(Steward Observatory, University of Arizona)
• Naofumi Fujishiro(Koyama Astronomical Observatory, Kyoto Sangyo University)
• Tomotsugu Goto(National Tsing Hua University)
• Masatoshi Imanishi(Subaru Telescope)
• Hanae Inami(CRAL, Observatoire de Lyon)
• Daisuke Ishihara(Graduate School of Science, Nagoya University)
• Hidehiro Kaneda(Graduate School of Science, Nagoya University)
• Kotaro Kohno(Institute of Astronomy, School of Science, the University of Tokyo)
• Yusei Koyama(Subaru Telescope)
• Hideo Matsuhara(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency)
• Shuji Matsuura(Department of Physics, School of Science and Technology, Kwansei Gakuin University)
• Tohru Nagao(Research Center for Space and Cosmic Evolution, Ehime University)
• Youichi Ohyama(Institute of Astronomy and Astrophysics, Academia Sinica)
• Takashi Onaka(Department of Astronomy, Graduate School of Science, the University of Tokyo)
• Shinki Oyabu(Graduate School of Science, Nagoya University)
• Chiris Pearson(RAL Space, CCLRC Rutherford Appleton Laboratory)
• Itsuki Sakon(Institute of Astronomy and Astrophysics, Academia Sinica)
• Tsutomu T. Takeuchi(Graduate School of Science, Nagoya University)
• Keisuke Tomita(Graduate School of Science, Nagoya University)
• Toru Yamada(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency)
• Mitsuhosi Yamagishi(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency)