INFRARED SPECTRAL ENERGY DISTRIBUTION OF GALAXIES IN THE AKARI ALL SKY SURVEY: CORRELATIONS WITH GALAXY PROPERTIES AND THEIR PHYSICAL ORIGIN

R. Makiya, T. Totani, T.T. Takeuchi, M. Nagashima, M.A.R. Kobayashi
2012 Publications of The Korean Astronomical Society  
We will report our recent study on the properties of more than 1,600 galaxies detected by the AKARI All-Sky Survey with physical quantities based on optical and 21-cm observations, to understand the physics determining the infrared spectral energy distribution (Totani et al., 2011) . We discover a tight linear correlation for normal star-forming galaxies between the radiation field strength of dust heating (corresponding to dust temperature) and the galactic-scale infrared radiation field, L
more » ... diation field, L TIR /R 2 . This is the tightest correlation of dust temperature ever known, and the dispersion along the mean relation is 13% in dust temperature. This relation can be explained physically by a thin layer of heating sources embedded in a thicker, optically-thick dust screen. We also find that the number of galaxies sharply drops when galaxies become optically thin against dust-heating radiation, indicating that a feedback process to galaxy formation (e.g., by the photoelectric heating) is working when dust-heating radiation is not self-shielded on a galactic scale. We discuss implications from these findings for the M HI -size relation, the Kennicutt-Schmidt relation, and galaxy formation in the cosmological context.
doi:10.5303/pkas.2012.27.4.325 fatcat:flnbykn3ifen7pbb775u5w4h7a