A CO(3-2) survey of a merging sequence of luminous infrared galaxies

Дата и время публикации : 2010-04-15T15:10:35Z

Авторы публикации и институты :
J. Leech
K. G. Isaak
P. P. Papadopoulos
Y. Gao
G. R. Davis

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: 17 pages, 8 figures and 4 tables. Accepted to appear in the Monthly Notices of the Royal Astronomical Society, 31st March 2010. The definitive version is available at www.blackwell-synergy.com.
Первичная категория: astro-ph.CO

Все категории : astro-ph.CO

Краткий обзор статьи: Luminous infrared galaxies ($L_{rm{IR}}>10^{11} L_{odot}$) are often associated with interacting galactic systems and are thought to be powered by merger–induced starbursts and/or dust–enshrouded AGN. In such systems, the evolution of the dense, star forming molecular gas as a function of merger separation is of particular interest. Here, we present observations of the CO(3-2) emission from a sample of luminous infrared galaxy mergers that span a range of galaxy-galaxy separations. The excitation of the molecular gas is studied by examining the CO(3-2)/CO(1-0) line ratio, $r_{31}$, as a function of merger extent. We find these line ratios, $r_{31}$, to be consistent with kinetic temperatures of $T_k$=(30–50) K and gas densities of $n_{rm{H}_2}=10^3 rm{cm}^{-3}$. We also find weak correlations between $r_{31}$ and both merger progression and star formation efficiency ($L_{rm{fIR}} / L_{rm{CO(1-0)}}$). These correlations show a tendency for gas excitation to increase as the merger progresses and the star formation efficiency rises. To conclude, we calculate the contributions of the CO(3-2) line to the 850 $mu$m fluxes measured with SCUBA, which are seen to be significant ($sim$24%).

Category: Physics