The search for molecular outflows in local volume AGNs with Herschel-pacs

We present the results from a systematic search for galactic-scale, molecular (OH 119 μm) outflows in a sample of 52 Local Volume ($d<50$ Mpc) Burst Alert Telescope detected active galactic nuclei (BAT AGNs) with Herschel-PACS. We combine the results from our analysis of the BAT AGNs with the published Herschel/PACS data of 43 nearby ($z<0.3$) galaxy mergers, mostly ultra-luminous infrared galaxies (ULIRGs) and QSOs. The objects in our sample of BAT AGNs have, on average, $\sim 10\text{--}100$ times lower AGN luminosities, star formation rates, and stellar masses than those of the ULIRG and QSO samples. OH 119 μm is detected in 42 of our BAT AGN targets. Evidence for molecular outflows (i.e., OH absorption profiles with median velocities more blueshifted than −50 km s⁻¹ and/or blueshifted wings with 84% velocities less than −300 km s⁻¹) is seen in only four BAT AGNs (NGC 7479 is the most convincing case). Evidence for molecular inflows (i.e., OH absorption profiles with median velocities more redshifted than 50 km s⁻¹) is seen in seven objects, although an inverted P-Cygni profile is detected unambiguously in only one object (Circinus). Our data show that both the starburst and AGN contribute to driving OH outflows, but the fastest OH winds require AGNs with quasar-like luminosities. We also confirm that the total absorption strength of OH 119 μm is a good proxy for dust optical depth as it correlates strongly with the 9.7 μm silicate absorption feature, a measure of obscuration originating in both the nuclear torus and host galaxy disk.