Poster Presentation

Dense gas in merger remnants

Author(s): Junko Ueda (SAO) et al.

Presenter: Junko Ueda (CfA)

Recently, AGN and stellar feedback has been recognized as an important process in galaxy evolution because galactic winds and outflows driven by AGN and starburst could blow out large amounts of the surrounding gas, quenching star formation. We have conducted HCN (1-0) observations of 16 local merger remnants, which have molecular gas disks, using the Large Millimeter Telescope (LMT). Our sample is taken from the sample of our previous SMA/ALMA study. We find that half of 16 sources have large line widths of the HCN compared to the CO. While the HCN line profiles of local galaxies have the same line widths as the CO line, several galaxies with AGNs and active nuclear starbursts have large line widths of the HCN. We thus suggest that the large line widths found in our sample may result from galactic winds and outflows driven by AGNs and starbursts. Furthermore, we investigate the relation between the ratio of the line width (FWHM(HCN)/(CO)) and the relative size of the molecular gas disk detected in the CO. While the statistics are small, we find that sources with large (>1.1) FWHM(HCN)/(CO) have small relative size of the molecular gas disk. If the large line widths of the HCN result from AGN and stellar feedback, this suggests that the feedback may affect the distribution of molecular gas. We will show results of follow-up HCN observations with SMA if the data are obtained.