We report the results from a systematic search for molecular (OH 119 µm) outflows with Herschel-PACS 1 in a sample of 43 nearby (z < 0.3) galaxy mergers, mostly ultraluminous infrared galaxies (ULIRGs) and QSOs. We find that the character of the OH feature (strength of the absorption relative to the emission) correlates with that of the 9.7-µm silicate feature, a measure of obscuration in ULIRGs. Unambiguous evidence for molecular outflows, based on the detection of OH absorption profiles with median velocities more blueshifted than −50 km

Powerful winds driven by active galactic nuclei are often thought to affect the evolution of both supermassive black holes and their host galaxies, quenching star formation and explaining the close relationship between black holes and galaxies. Recent observations of large-scale molecular outflows in ultraluminous infrared galaxies support this quasar-feedback idea, because they directly trace the gas from which stars form. Theoretical models suggest that these outflows originate as energy-conserving flows driven by fast accretion-disk winds. Proposed connections between large-scale molecular outflows and accretion-disk activity in ultraluminous galaxies were incomplete because no accretion-disk wind had been detected. Conversely, studies of powerful accretion-disk winds have until now focused only on X-ray observations of local Seyfert galaxies and a few higher-redshift quasars. Here we report observations of a powerful accretion-disk wind with a mildly relativistic velocity (a quarter that of light) in the X-ray spectrum of IRAS F11119+3257, a nearby (redshift 0.189) optically classified type 1 ultraluminous infrared galaxy hosting a powerful molecular outflow. The active galactic nucleus is responsible for about 80 per cent of the emission, with a quasar-like luminosity of 1.5 × 10(46) ergs per second. The energetics of these two types of wide-angle outflows is consistent with the energy-conserving mechanism that is the basis of the quasar feedback in active galactic nuclei that lack powerful radio jets (such jets are an alternative way to drive molecular outflows).

We report on the energetics of molecular outflows in 14 local Ultraluminous Infrared Galaxies (ULIRGs) that show unambiguous outflow signatures (P-Cygni profiles or high-velocity absorption wings) in the far-infrared lines of OH measured with the Herschel/PACS spectrometer. All sample galaxies are gas-rich mergers at various stages of the merging process. Detection of both ground-state (at 119 and 79 µm) and one or more radiatively-excited (at 65 and 84 µm) lines allows us to model the nuclear gas ( 300 pc) as well as the more extended components using spherically symmetric radiative transfer models. Reliable models and the corresponding energetics are found in 12 of the 14 sources. The highest molecular outflow velocities are found in buried sources, in which slower but massive expansion of the nuclear gas is also observed. With the exception of a few outliers, the outflows have momentum fluxes of (2 − 5) × L IR /c and mechanical luminosities of (0.1 − 0.3)% of L IR . The moderate momentum boosts in these sources ( 3) suggest that the outflows are mostly momentum-driven by the combined effects of AGN and nuclear starbursts, as a result of radiation pressure, winds, and supernovae remnants. In some sources (∼ 20%), however, powerful (10 10.5−11 L ⊙ ) AGN feedback and (partially) energy-conserving phases are required, with momentum boosts in the range 3 − 20. These outflows appear to be stochastic, strong-AGN feedback events that occur throughout the merging process. In a few sources, the outflow activity in the innermost regions has subsided in the last ∼ 1 Myr. While OH traces the molecular outflows at sub-kpc scales, comparison of the masses traced by OH with those previously inferred from tracers of more extended outflowing gas suggests that most mass is loaded (with loading factors ofṀ /SFR = 1 − 10) from the central galactic cores (a few × 100 pc), qualitatively consistent with an ongoing inside-out quenching of star formation. Outflow depletion timescales are < 10 8 yr, shorter than the gas consumption timescales by factors of 1.1 − 15, and are anti-correlated with the AGN luminosity.

We have studied the relationship between the [O IV] λ25.89µm emission line luminosities, obtained from Spitzer spectra, the X-ray continua in the 2-10 keV band, primarily from ASCA, and the 14-195 keV band obtained with the SWIFT/Burst Alert Telescope (BAT), for a sample of nearby (z < 0.08) Seyfert galaxies. For comparison, we have examined the relationship between the [O III] λ5007, the 2-10 keV and the 14-195 keV luminosities for the same set of objects. We find that both the [O IV] and [O III] luminosities are well-correlated with the BAT luminosities. On the other hand, the [O III] luminosities are bettercorrelated with 2-10 keV luminosities than are those of [O IV]. When comparing [O IV] and [O III] luminosities for the different types of galaxies, we find that the Seyfert 2's have significantly lower [O III] to [O IV] ratios than the Seyfert 1's. We suggest that this is due to more reddening of the narrow line region (NLR) of the Seyfert 2's. Assuming Galactic dust to gas ratios, the average amount of extra reddening corresponds to a hydrogen column density of ∼ few times 10 21 cm −2 , which is a small fraction of the X-ray absorbing columns in the Seyfert 2's. The combined effects of reddening and the X-ray absorption are the probable reason why the [O III] versus 2-10 keV correlation is better than the [O IV] versus 2-10 keV, since the [O IV] λ25.89µm emission line is much less affected by extinction. We present a grid of photoionization models used to calculate the physical conditions present in the [O IV] region. We find that the [O IV] comes from higher ionization states and lower density regions than previous studies had determined for [O III]. Overall, we find the [O IV] to be an accurate and truly isotropic indicator of the power of the AGN. This suggests that it can be useful in deconvolving the contribution of the AGN and starburst to the spectrum of Compton-thick and/or X-ray weak sources.

In Tombesi et al. (2015), we reported the first direct evidence for a quasar accretion disk wind driving a massive molecular outflow. The target was F11119+3257, an ultraluminous infrared galaxy (ULIRG) with unambiguous type-1 quasar optical broad emission lines. The energetics of the accretion disk wind and molecular outflow were found to be consistent with the predictions of quasar feedback models where the molecular outflow is driven by a hot energy-conserving bubble inflated by the inner quasar accretion disk wind. However, this conclusion was uncertain because the energetics of the outflowing molecular gas were estimated from the optically thick OH 119 µm transition profile observed with Herschel. Here, we independently confirm the presence of the molecular outflow in F11119+3257, based on the detection of broad wings in the CO(1−0) profile derived from ALMA observations. The broad CO(1−0) line emission appears to be spatially extended on a scale of at least ∼7 kpc from the center. Mass outflow rate, momentum flux, and mechanical power of 7 L AGN are inferred from these data, assuming a CO−to−H 2 conversion factor appropriate for a ULIRG (R 7 is the radius of the outflow normalized to 7 kpc and L AGN is the AGN luminosity). These rates are time-averaged over a flow time scale of 7 × 10 6 yrs. They are similar to the OH-based rates time-averaged over a flow time scale of 4× 10 5 yrs, but about a factor 4 smaller than the local ("instantaneous"; 10 5 yrs) OH-based estimates cited in Tombesi et al. The implications of these new results are discussed in the context of time-variable quasar-mode feedback and galaxy evolution. The need for an energy-conserving bubble to explain the molecular outflow is also re-examined.

We investigate the location of an ultra-hard X-ray selected sample of AGN from the Swift Burst Alert Telescope (BAT) catalog with respect to the main sequence (MS) of star-forming galaxies using Herschel -based measurements of the SFR and M * 's from Sloan Digital Sky Survey (SDSS) photometry where the AGN contribution has been carefully removed. We construct the MS with galaxies from the Herschel Reference Survey and Herschel Stripe 82 Survey using the exact same methods to measure the SFR and M * as the Swift /BAT AGN. We find a large fraction of the Swift /BAT AGN lie below the MS indicating decreased specific SFR (sSFR) compared to non-AGN galaxies. The Swift /BAT AGN are then compared to a high-mass galaxy sample (COLD GASS), where we find a similarity between the AGN in COLD GASS and the Swift /BAT AGN. Both samples of AGN lie firmly between star-forming galaxies on the MS and quiescent galaxies far below the MS. However, we find no relationship between the X-ray luminosity and distance from the MS. While the morphological distribution of the BAT AGN is more similar to star-forming galaxies, the sSFR of each morphology is more similar to the COLD GASS AGN. The merger fraction in the BAT AGN is much higher than the COLD GASS AGN and star-forming galaxies and is related to distance from the MS. These results support a model in which bright AGN tend to be in high mass star-forming galaxies in the process of quenching which eventually starves the supermassive black hole itself.

Abstract.A detailed analysis of the radiative and Auger de-excitation channels of K-shell vacancy states in Fe -Fe  has been carried out. Level energies, wavelengths, A-values, Auger rates and fluorescence yields have been calculated for the lowest fine-structure levels populated by photoionization of the ground state of the parent ion. Different branching ratios, namely Kα 2 /Kα 1 , Kβ/Kα, KLM/KLL, KMM/KLL, and the total K-shell fluorescence yields, ω K , obtained in the present work have been compared with other theoretical data and solid-state measurements, finding good general agreement with the latter. The Kα 2 /Kα 1 ratio is found to be sensitive to the excitation mechanism. From these comparisons it has been possible to estimate an accuracy of ∼10% for the present transition probabilities.

We report on the Herschel/PACS observations of OH in Mrk 231, with detections in nine doublets observed within the PACS range, and present radiative-transfer models for the outflowing OH. Clear signatures of outflowing gas are found in up to six OH doublets with different excitation requirements. At least two outflowing components are identified, one with OH radiatively excited, and the other with low excitation, presumably spatially extended and roughly spherical. Particularly prominent, the blue wing of the absorption detected in the in-ladder 2 Π 3/2 J = 9/2−7/2 OH doublet at 65 μm, with E lower = 290 K, indicates that the excited outflowing gas is generated in a compact and warm (circum)nuclear region. Because the excited, outflowing OH gas in Mrk 231 is associated with the warm, far-infrared continuum source, it is most likely more compact (diameter of ∼200−300 pc) than that probed by CO and HCN. Nevertheless, its mass-outflow rate per unit of solid angle as inferred from OH is similar to that previously derived from CO, > ∼ 70 × (2.5 × 10 −6 /X OH ) M yr −1 sr −1 , where X OH is the OH abundance relative to H nuclei. In spherical symmetry, this would correspond to > ∼ 850 × (2.5 × 10 −6 /X OH ) M yr −1 , though significant collimation is inferred from the line profiles. The momentum flux of the excited component attains ∼15 L AGN /c, with an OH column density of (1.5−3) × 10 17 cm −2 and a mechanical luminosity of ∼10 11 L . In addition, the detection of very excited, radiatively pumped OH peaking at central velocities indicates the presence of a nuclear reservoir of gas rich in OH, plausibly the 130 pc scale circumnuclear torus previously detected in OH megamaser emission, that may be feeding the outflow. An exceptional 18 OH enhancement, with OH/ 18 OH < ∼ 30 at both central and blueshifted velocities, is most likely the result of interstellar-medium processing by recent starburst and supernova activity within the circumnuclear torus or thick disk.