2017/12/18 by Loreto Barcos-Muñoz, Susanne Aalto, Todd A. Thompson +6 · 1 citation
Physics and Astronomy · #astro-ph.GA
paper · pdf · doi:10.3847/2041-8213/aaa28d
Accepted for publication in ApJL
arxiv created 2017/12/18 · arxiv updated 2018/02/14
We present the first spatially and spectrally resolved image of the molecular outflow in the western nucleus of Arp 220. The outflow, seen in HCN~(1--0) by ALMA, is compact and collimated, with extension \lesssim 120 pc. Bipolar morphology emerges along the minor axis of the disk, with redshifted and blueshifted components reaching maximum inclination-corrected velocity of ∼ ± 840 km s-1. The outflow is also seen in CO and continuum emission, the latter implying that it carries significant dust. We estimate a total mass in the outflow of \geqslant 106 M\odot, a dynamical time of ∼ 105 yr, and mass outflow rates of \geqslant55 M\odot yr-1 and \geqslant 15 M\odot yr-1 for the northern and southern lobes, respectively. Possible driving mechanisms include supernovae energy and momentum transfer, radiation pressure feedback, and a central AGN. The latter could explain the collimated morphology of the HCN outflow, however we need more complex theoretical models, including contribution from supernovae and AGN, to pinpoint the driving mechanism of this outflow.