Molecular Gas Outflow in the Starburst Galaxy NGC 1482

Abstract

Galactic winds are essential to the regulation of star formation in galaxies. To study the distribution and dynamics of molecular gas in wind, we imaged the nearby starburst galaxy NGC 1482 in CO (J = 1 → 0) at a resolution of 1″ (≈100 pc) using the Atacama Large Millimeter/submillimeter Array. Molecular gas is detected in a nearly edge-on disk with a radius of 3 kpc and a biconical outflow emerging from the central 1 kpc starburst and extending to at least 1.5 kpc perpendicular to the disk. In the outflow, CO gas is distributed approximately as a cylindrically symmetrical envelope surrounding the warm and hot ionized gas traced by Hα and soft X-rays. The velocity, mass outflow rate, and kinetic energy of the molecular outflow are ${v}_{{\rm{w}}}\sim 100\,\mathrm{km}\,{{\rm{s}}}^{-1}$ , ${\dot{M}}_{{\rm{w}}}\sim 7\,{M}_{\odot }\,{\mathrm{yr}}^{-1}$ , and ${E}_{{\rm{w}}}\sim 7\times {10}^{54}\,\mathrm{erg}$ , respectively. ${\dot{M}}_{{\rm{w}}}$ is comparable to the star formation rate ( ${\dot{M}}_{{\rm{w}}}/\mathrm{SFR}\sim 2$ ) and E_w is ∼1% of the total energy released by stellar feedback in the past $1\times {10}^{7}\,\mathrm{yr}$ , which is the dynamical timescale of the outflow. The results indicate that the wind is starburst driven.