ALMA and high redshift dusty starburst mergers

Abstract

By using a new numerical code for deriving the spectral energy distributions of galaxies, we have investigated the time evolution of morphological properties, the star formation rate, and the submillimeter flux at 850 $\hat{I}¼$m in high-redshift ($z$) dusty starburst mergers with mass ratio ($m_2$) of two disks ranging from 0.1 (minor merger) to 1.0 (major one). We found that the maximum star-formation rate, the degree of dust extinction, and the 850 $\hat{I}¼$m flux are larger for mergers with larger $m_2$. The 850 $\hat{I}¼$m flux from mergers at 1.5 $\le z\le$ 3.0 in the observer frame is found to be a few mJy for major merger cases, and at most $\sim$ 100 $\hat{I}¼$Jy for minor ones. This result suggests that only high-redshift major mergers are now detected by SCUBA with the current 850 $\hat{I}¼m$ detection limit of a few mJy. These results imply that LMSA (ALMA) with the expected detection limit of the order of 10 $\hat{I}¼$Jy at 850 $\hat{I}¼m$ can be used to study high-redshift mergers with variously different $m_2$, and thus provide an important clue to the formation of galaxies in a high-redshift universe.

11 pages 3 figures, PASJ in press