Title: AzTEC/ASTE 1.1-mm Survey of the AKARI Deep Field South
Author(s): B. Hatsukade, K. Kohno, Y. Tamura (University of Tokyo), K. Nakanishi, D. Iono, R. Kawabe, T. Tosaki (Nobeyama Radio Observatory), S. Matsuura, M. Shirahata, S. Oyabu, T. Takagi (ISAS/JAXA), T. T. Takeuchi (Nagoya University), G. W. Wilson, M. S. Yun, K. S. Scott, J. E. Austermann, T. Perera (University of Massachusetts), D. H. Hughes, I. Aretxaga (INAOE), K. Tanaka (Keio University), H. Matsuo, H. Ezawa (NAOJ), H. Hanami (Iwate University), Y. Ohyama (ASIAA), and AzTEC/ASTE ADFS team
Abstract:Submillimeter Galaxies (SMGs) are dusty, massively star forming galaxies (star formation rates ~ 10^2-10^3 Msun/yr) at the early universe, and are thought to be progenitors of present massive ellipticals. It is considered that these massive galaxies form at dense regions of dark matter, and therefore observations of SMGs provide us with the information on the formation of large-scale structure. Since SMGs are highly obscured by dust, it is essential to observe at submillimeter wavelengths to reveal cosmic star formation and galaxy formation.
We conduct 1.1-mm deep surveys of AKARI Deep Field South (ADFS) using AzTEC camera, a 144-element bolometer on the ASTE telescope at Atacama, Chile. The ADFS is known to be the lowest-cirrus region near the South Ecliptic Pole, and therefore is advantageous for deep observations of distant universe at far-IR wavelengths. We covered approximately 1000 arcmin^2 with an rms noise of 0.5-1.0 mJy and detected ~100 sources (>3.5 sigma). This survey exceeds the previous large submillimeter surveys in area and source reliability. We create number counts toward much fainter fluxes (<0.5 mJy). The counts are small compared to COSMOS and GOODS-N fields, and now we see variety in number counts among "blank fields". Most of the sources are undetected by AKARI FIS (50-180 um) bands and ~2/3 of sources do not have 21-cm radio counterparts, suggesting that those undetected by 90 um / 21 cm are likely to be at z > 2, considering detection limits.
Since the ADFS is observable only at southern hemisphere, collaboration between southern telescopes are essential. I present a future plan for follow-up observations of the AzTEC sources using the Gemini-South.