Molecular Gas in NUclei of GAlaxies (NUGA) XIII. The interacting Seyfert 2/LINER galaxy NGC 5953

TL;DR

This study maps molecular gas in NGC 5953, revealing a regular rotating disk with limited gas inflow toward the nucleus, suggesting the AGN is not actively fueled currently.

Contribution

First detailed CO maps of NGC 5953 showing gas distribution, kinematics, and gravitational torques, indicating limited gas inflow and no active AGN fueling.

Findings

Molecular gas distributed over a 2.2 kpc disk with off-center peaks.

Gas kinematics consistent with a regular rotating disk.

Gravity torques are mostly positive, inhibiting gas inflow.

Abstract

We present $^{12}$CO(1--0) and $^{12}$CO(2--1) maps of the interacting Seyfert 2/LINER galaxy NGC 5953 obtained with the IRAM interferometer at resolutions of 2\farcs1 $\times$ 1\farcs4 and 1\farcs1 $\times$ 0\farcs7, respectively. The CO emission is distributed over a disk of diameter $\sim$16\arcsec ($\sim$2.2 kpc), within which are several, randomly distributed peaks. The strongest peak does not coincide with the nucleus, but is instead offset from the center, $\sim2-3^{\prime\prime}$ ($\sim$340 pc) toward the west/southwest. The kinematics of the molecular component are quite regular, as is typical of a rotating disk. We also compared the $^{12}$CO distribution of NGC 5953 with observations at other wavelengths in order to study correlations between different tracers of the interstellar medium. Using NIR images, we computed the gravity torques exerted by the stellar potential on the gas. The torques are predominantly positive in both $^{12}$CO(1--0) and $^{12}$CO(2--1), suggesting that gas is not flowing into the center, and less than 5% of the gas angular momentum is exchanged in each rotation. This comes from the regular and almost axisymmetric total mass and gas distributions in the center of the galaxy. In NGC 5953, the AGN is apparently not being actively fueled in the current epoch.