Discovery of an active galactic nucleus driven molecular outflow in the local early-type galaxy NGC 1266

Abstract

We report the discovery of a powerful molecular wind from the nucleus of the non-interacting nearby S0 field galaxy NGC 1266. The single-dish CO profile exhibits emission to +/- 400 km s(-1) and requires a nested Gaussian fit to be properly described. Interferometric observations reveal a massive, centrally concentrated molecular component with a mass of 1.1 x 10(9) M-circle dot and a molecular outflow with a molecular mass of approximate to 2.4 x 10(7) M-circle dot. The molecular gas close to the systemic velocity consists of a rotating, compact nucleus with a mass of about 4.1 x 10(8) M-circle dot within a radius of approximate to 60 pc. This compact molecular nucleus has a surface density of approximate to 2.7 x 10(4) M-circle dot pc(-2), more than two orders of magnitude larger than that of giant molecular clouds in the disk of the Milky Way, and it appears to sit on the Kennicutt-Schmidt relation despite its extreme kinematics and energetic activity. We interpret this nucleus as a disk that confines the outflowing wind. A mass outflow rate of approximate to 13 M-circle dot yr(-1) leads to a depletion timescale of less than or similar to 85 Myr. The star formation in NGC 1266 is insufficient to drive the outflow, and thus it is likely driven by the active galactic nucleus. The concentration of the majority of the molecular gas in the central 100 pc requires an extraordinary loss of angular momentum, but no obvious companion or interacting galaxy is present to enable the transfer. NGC 1266 is the first known outflowing molecular system that does not show any evidence of a recent interaction.