AKARI Far-Infrared all sky survey

¹ Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo, 153-8902, Japan
² Department of Physics & Astronomy, The Open University, Milton Keynes, MK7 6BJ, United Kingdom
³ Space Science and Technology Dept., The Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
⁴ Instituto de Astronomiac, Geofίsica e Ciências Atmosféricas, Departamento de Astronomica, Universidade de São Paulo, Rua do Matão 1226, Cidade Universitaria 05508-900, São Paulo SP, Brazil
⁵ Astronomical Institute, Graduate School of Science, Tohoku university, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
⁶ Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Yoshinodai 3-1-1, Sagamihara, Kanagawa, 229-8510, Japan
⁷ Department of Physics and Astrophysics, Nagoya University, Furocho, Chikusa, Nagoya, 464-8602, Japan
⁸ Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan

Abstract

We demonstrate the capability of AKARI for mapping diffuse far-infrared emission and achieved reliability of allsky diffuse map. We have conducted an all-sky survey for more than 94% of the whole sky during the cold phase of AKARI observations in 2006 Feb. ­ 2007 Aug. The survey in the far-infrared waveband covers 50 μm ­ 180 μm with four bands centered at 65 μm, 90 μm, 140 μm, and 160 μm and spatial resolution of 30ʹʹ ­ 40ʹʹ (FWHM).This survey has allowed us to make a revolutionary improvement compared to the IRAS survey that was conducted in 1983 in both spatial resolution and sensitivity after more than a quarter of a century. Additionally, it will provide us the first all-sky survey data with high-spatial resolution beyond 100 μm. Considering the extreme importance of the AKARI far-infrared diffuse emission map, we are now investigating carefully the quality of the data for possible release of the archival data. Critical subjects in making an image of diffuse emission from the detected signal are the transient response and the long-term stability of the farinfrared detectors. Quantitative evaluation of these characteristics is the key to achieve sensitivity comparable to or better than that for point sources (< 20 ­ 95 [MJy/sr]). We describe current activities and progress that are focused on making high quality all-sky survey images of the diffuse far-infrared emission.