Cosmic star formation history and AGN evolution near and far: AKARI reveals both.
Tomo Goto1*, Nagisa Oi2, Youichi Ohyama3, Hideo Matsuhara2, AKARI Team2
1IoA, NTHU, Hsinchu, Taiwan
2ISAS, JAXA, Sagamihara, Japan
3ASIAA, Taipei, Taiwan
* presenting author:Tomo Goto, email:tomo@phys.nthu.edu.tw
Understanding infrared (IR) luminosity is fundamental to understanding the cosmic star formation history and AGN evolution, since their most intense stages are often obscured by dust. Japanese infrared satellite, AKARI, provided unique data sets to probe this both at low and high redshift; the AKARI all sky survey in 6 bands (9-160um), and the AKARI NEP Deep survey in 9 bands (2-24um).

The AKARI performed all sky survey in 6 IR bands (9, 18, 65, 90, 140, and 160um) with 3-10 times better sensitivity than IRAS, covering the crucial far-IR wavelengths across the peak of the dust emission. Combined with a better spatial resolution, AKARI can much more precisely measure the total infrared luminosity (L_TIR) of individual galaxies, and thus, the total infrared luminosity density of the local Universe.

In the AKARI NEP deep field, AKARI has obtained deep images in the mid-infrared (IR), covering 0.6 sq.deg of the NEP deep field. However, our previous work was limited to the central area of 0.25 sq.deg due to the lack of optical coverage. To rectify the situation, we recently obtained CFHT optical and near-IR images over the entire AKARI NEP deep field. Using this, we constructed restframe 8um, 12um, and total infrared (TIR) luminosity functions (LFs) at 0.15<z<2.2. A continuous 9-band filter coverage in the mid-IR wavelength (2.4, 3.2, 4.1, 7, 9, 11, 15, 18, and 24um) by the AKARI satellite allowed us to estimate restframe 8um and 12um luminosities without using a large extrapolation based on a SED fit, which was the largest uncertainty in previous work.

By combining these two results, we reveal dust-hidden cosmic star formation history and AGN evolution from z=0 to z=2.2, all probed by the AKARI satellite.


Keywords: cosmic star formation history, cosmic black hole accretion history, space infrared telescope