| dc.description.abstract | In this work, my collaborators and I use sub-millimeter observations carried out with the QTR{it}{Sub-millimeter Common User Bolometre Array} (QTR{it}{SCUBA}) on QTR{it}{James Clerk Maxwell Telescope} (QTR{it}{JCMT}) to study a sample of 10 interacting LIRGs. The benefit of QTR{it}{SCUBA} observation is that QTR{it}{SCUBA} is a camera with high sensitivity and spacial resolutions. It can achieve the detail study in both morphology and spectral energy distribution of colder dust components in our samples. Like previous works with mid-infrared and CO line emission, our samples include galaxy pairs at the early (presumably pre-starburst), intermediate and late stages of interaction. This sequence is essential for locating the onset of starbursts and developing mergers, and allowing quantitative measurements of such parameters as flux ratios $S_{450mu m}/S_{850mu m}$, dust temperatures, dust mass, and the star formation efficiencies as a function of merger stage.
I also discuss the constraints imposed by cold dust components ($T_{dust}sim 10$ K), molecular gas-to-dust mass ratios and flux ratios of CO (J=3-2) line emission, which lies in the transmission band of QTR{it}{SCUBA} 850 $mu m$ filter, to CO (J=1-0). If the flux ratio is small ($ll 1$), which means that CO (J=3-2) is weak in 850 $mu m$ waveband, the cold dust contributes a large fraction of total dust content. It suggests that molecular gas-to-dust ratio in these galaxies is not very different from the Galactic value. This result can solve the problem that the molecular gas-to-dust mass ratios in LIRGs are about 10 times higher than that ratio in our Galaxy, which are estimated from the CO and far-infrared observations. On the other hand, if CO (J=3-2) contributes a significant fraction of 850 $mu m$ measurements, the cold dust would have less mass than other QTR{it}{SCUBA} results suggested. I also get that the upper limit of CO (J=3-2) / CO (J=1-0) emission. The value in my cases is close to 1 which shows that the two CO transition lines are both optically thick. Such investigation is important for the understanding of the actual physical conditions of ISM in starburst galaxies and mergers. | en_US |