http://arxiv.org/abs/2304.04004
We present ALMA CO(2-1) observations of the Seyfert 2 galaxy NGC 3281 at $\sim$ 100 pc spatial resolution. This galaxy was previously known to present a bi-conical ionised gas outflow extending to 2 kpc from the nucleus. The analysis of the CO moment and channel maps, as well as kinematic modelling reveals two main components in the molecular gas: one rotating in the galaxy plane and another outflowing and extending up to $\sim$ 1.8 — 2.6 kpc from the nucleus, partially encasing the ionised component. The mass of the outflowing molecular gas component is $M_{\mathrm{mol},\mathrm{out}}$ = $(2.5\pm1.6){\times}10^{6}$ $\rm{M_{\odot}}$, representing $\sim$ 1.7 — 2 % of the total molecular gas seen in emission within the inner 2.3 kpc. The corresponding mass outflow rate and power are $\dot{M}{\mathrm{mol},\mathrm{out}}$ = 0.12 — 0.72 $\rm{M{\odot} yr^{-1}}$ and $\dot{E}_{\mathrm{mol},\mathrm{out}}$ = (0.045 — 1.6) ${\times} 10^{40}$ $\rm{erg s^{-1}}$, which translates to a kinetic coupling efficiency with the AGN power of only $10^{-4}$ — 0.02 %. This value reaches up to 0.1 % when including both the feedback in the ionised and molecular gas, as well as considering that only part of the energy couples kinetically with the gas. Some of the non-rotating CO emission can also be attributed to inflow in the galaxy plane towards the nucleus. The similarity of the CO outflow — encasing the ionised gas one and the X-ray emission — to those seen in other sources, suggests that this may be a common property of galactic outflows.
B. Oliveira, T. Storchi-Bergmann, R. Morganti, et. al.
Tue, 11 Apr 23
41/63
Comments: 13 pages, 11 figures. Accepted for publication in MNRAS