SHOCKED POSTSTARBURST GALAXY SURVEY. II. THE MOLECULAR GAS CONTENT AND PROPERTIES OF A SUBSET OF SPOGs

Alatalo, Katherine; Lisenfeld, Ute; Lanz, Lauranne; Appleton, Philip N.; Ardila, Felipe; Cales, Sabrina L.; Kewley, Lisa J.; Lacy, Mark; Medling, Anne M.; Nyland, Kristina; Rich, Jeffrey A.; Urry, C. Meg
2016
ASTROPHYSICAL JOURNAL
DOI
10.3847/0004-637X/827/2/106
We present CO(1-0) observations of objects within the Shocked POststarburst Galaxy Survey taken with the Institut de Radioastronomie Millimetrique 30 m single dish and the Combined Array for Research for Millimeter Astronomy interferometer. Shocked poststarburst galaxies (SPOGs) represent a transitioning population of galaxies, with deep Balmer absorption (EWH delta > 5 angstrom), consistent with an intermediate-age (A-star) stellar population, and ionized gas line ratios inconsistent with pure star formation. The CO(1-0) subsample was selected from SPOGs detected by the Wide-field Infrared Survey Explorer with 22 mu m flux detected at a signal-to-noise ratio. (S/N) > 3. Of the 52 objects observed in CO(1-0), 47 are detected with S/N > 3. A large fraction (37%-46% +/- 7%) of our CO-SPOG sample were visually classified as morphologically disrupted. The H-2 masses detected were between 10(8.7-10.8) M-circle dot, consistent with the gas masses found in normal galaxies, though approximately an order of magnitude larger than the range seen in poststarburst galaxies. When comparing the 22 mu m and CO(1-0) fluxes, SPOGs diverge from the normal star-forming relation, having 22 mu m fluxes in excess of the relation by a factor of = 4.91(-0.39)(+0.42), suggestive of the presence of active galactic nuclei (AGNs). The Na I D characteristics of CO-SPOGs show that it is likely that many of these objects host interstellar winds. Objects with. large Na I D enhancements also tend to emit in the radio, suggesting possible AGN. driving of neutral winds.