Revealing the cosmic star formation history hidden by dust
Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI, 96822, USA e-mail: firstname.lastname@example.org
2 National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan
3 Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510, Japan
4 Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
5 Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK
6 Department of Physics, University of Lethbridge, 4401 University Drive,Lethbridge, Alberta T1J 1B1, Canada
7 Astrophysics Group, Department of Physics, The Open University, Milton Keynes, MK7 6AA, UK
8 Laboratoire d'Astrophysique de Marseille, BP 8, Traverse du Siphon, 13376 Marseille Cedex 12, France
9 CEA-Saclay, Service d'Astrophysique, France
10 Academia Sinica, Institute of Astronomy and Astrophysics, Taiwan
11 Department of Physics and Astronomy, UCLA, Los Angeles, CA, 90095-1547, USA
12 Department of Physics & Astronomy, FPRD, Seoul National University, Shillim-Dong, Kwanak-Gu, Seoul 151-742, Korea
13 Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125, USA
14 Department of Astronomical Science, The Graduate University for Advanced Studies, Hayama, Miura, Kanagawa, 240-0193, Japan
15 Physics Section, Faculty of Humanities and Social Sciences, Iwate University, Morioka, 020-8550, Japan
16 TOME R&D Inc. Kawasaki, Kanagawa 213 0012, Japan
17 Asahikawa National College of Technology, 2-1-6 2-jo Shunkohdai, Asahikawa-shi, Hokkaido 071-8142, Japan
Accepted: 23 December 2009
Aims. Dust-obscured star-formation increases with increasing intensity and increasing redshift. We aim to reveal the cosmic star-formation history obscured by dust using deep infrared observation with AKARI.
Methods. We constructed restframe 8 μm, 12 μm, and total infrared (TIR) luminosity functions (LFs) at 0.15 < z < 2.2 using 4128 infrared sources in the AKARI NEP-deep field. A continuous filter coverage in the mid-IR wavelength (2.4, 3.2, 4.1, 7, 9, 11, 15, 18, and 24 μm) by the AKARI satellite allowed us to estimate restframe 8 μm and 12 μm luminosities without using a large extrapolation based on an SED fit, which was the largest uncertainty in previous work.
Results. We find that all 8 μm (0.38 < z < 2.2), 12 μm (0.15 < z < 1.16), and TIR LFs (0.2 < z <1.6) show continuous and strong evolution toward higher redshift. Our direct estimate of 8 μm LFs is useful since previous work often had to use a large extrapolation from the Spitzer 24 μm to 8 μm, where SED modeling is more difficult because of the PAH emissions. In terms of cosmic infrared luminosity density (ΩIR), which was obtained by integrating analytic fits to the LFs, we find good agreement with previous work at z<1.2. We find the ΩIR evolves as (1 + z). When we separate contributions to ΩIR by LIRGs and ULIRGs, we found more IR luminous sources are increasingly more important at higher redshift. We find that the ULIRG (LIRG) contribution increases by a factor of 10 (1.8) from z = 0.35 to z = 1.4.
Key words: infrared: galaxies / galaxies: luminosity function, mass function / galaxies: evolution / galaxies: high-redshift / galaxies: formation / galaxies: starburst
© ESO, 2010