Dense Molecular Gas in Nearby Gas-rich Active Galaxies

Дата и время публикации : 2011-08-08T16:33:26Z

Авторы публикации и институты :
Xuejian Jiang
Junzhi Wang
Qiusheng Gu

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: 12 pages, 7 figures, accepted for publication in MNRAS
Первичная категория: astro-ph.CO

Все категории : astro-ph.CO, astro-ph.GA

Краткий обзор статьи: We present 3 mm observations obtained with the IRAM 30-m telescope for ten nearby gas-rich active galaxies spanning three orders of magnitude in infrared luminosity. Emission lines of HCO+(1-0), HCN(1-0), and C2H(1-0) were simultaneously detected in most galaxies of our sample. We also tentatively detected the rare isotopic species, H13CN, HC15N and H13CO+ in up to four galaxies (IC 694, NGC 3690, NGC 4258 and NGC 6240). Our estimation shows that the optical depth of HCN is low to moderate in these galaxies (tau ~ 1-5). After comparing the intensity ratios of different molecular emission lines (HCN/HCO+, C2H/HCN, and C2H/HCO+) with the infrared luminosity (LIR), we find that in the infrared luminous sample of five composite (AGN+Starburst) galaxies, these ratios vary with LIR: the HCN/HCO+ ratio increases with LIR, which is consistent with previous studies, while there is a slight trend in the composite galaxies that both C2H/HCN and C2H/HCO+ ratios decrease with increasing LIR. Although our sample is limited, this trend may possibly imply a relation between the overall gas density and the infrared luminosity of galaxies.

Category: Physics