NGC 1266

NGC 1266 is a lenticular galaxy located in the constellation Eridanus. It is not currently undergoing a starburst, but it experienced an intense period of star formation that ended roughly 500 million years ago. The galaxy also hosts an obscured active galactic nucleus (AGN).

A massive molecular outflow, containing about 2.4 × 10⁷ solar masses of hydrogen, streams from the galaxy’s nucleus at a rate of 110 solar masses per year. However, less than 2% of this gas—around 2 solar masses per year—actually escapes the galaxy. The outflow is likely driven by momentum coupling to the AGN’s jet.

The current star-formation rate is about 0.87 solar masses per year, which is 50 to 150 times lower than expected for a galaxy with its properties. The leading explanation is that the AGN-driven outflow injects turbulence into the nuclear region, preventing gravitational collapse of molecular clouds. NGC 1266 is the first intermediate-mass galaxy known to show star formation suppression driven by an AGN.

Two competing hypotheses account for the galaxy’s nuclear activity and excess far-infrared emission: either a heavily obscured ultracompact starburst exists in the nucleus, or a powerful buried AGN is present beyond what other observations suggest. Both scenarios have difficulties. The central black hole is likely growing in line with the M–sigma relation, and the outflow will eventually remove most of the gas from the nucleus.