NGC 1266 AS A LOCAL CANDIDATE FOR RAPID CESSATION OF STAR FORMATION

Abstract

We present new Spectrographic Areal Unit for Research on Optical Nebulae\n(SAURON) integral-field spectroscopy and Swift Ultraviolet Optical Telescope\n(UVOT) observations of molecular outflow host galaxy NGC 1266 that indicate NGC\n1266 has experienced a rapid cessation of star formation. Both the SAURON maps\nof stellar population age and the Swift UVOT observations demonstrate the\npresence of young ($< 1$ Gyr) stellar populations within the central 1 kpc,\nwhile existing Combined Array for Research in Millimeter-wave Astronomy (CARMA)\nCO(1--0) maps indicate that the sites of current star formation are constrained\nto the inner few hundred parsecs of the galaxy only. The optical spectrum of\nNGC 1266 from Moustakas & Kennicutt (2006) reveal a characteristic\npost-starburst (K+A) stellar population and Davis et al. (2012) confirm that\nionized gas emission in the system originate from a shock. Galaxies with K+A\nspectra and shock-like ionized gas line ratios may comprise an important,\noverlooked segment of the post-starburst population, containing exactly those\nobjects in which the AGN is actively expelling the star-forming material. While\nAGN activity is not the likely driver of the post-starburst event that occurred\n500 Myr ago, the faint spiral structure seen in the Hubble Space Telescope\n(HST) Wide-field Camera 3 (WFC3) Y-, J- and H-band imaging seems to point to\nthe possibility of gravitational torques being the culprit. If the molecular\ngas were driven into the center at the same time as the larger scale galaxy\ndisk underwent quenching, the AGN might be able to sustain the presence of\nmolecular gas for $\\gtrsim 1$ Gyr by cyclically injecting turbulent kinetic\nenergy into the dense molecular gas via a radio jet, inhibiting star formation.\n