| 1. |
- Gonzalez-Alfonso, E., et al.
(författare)
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HIGH-LYING OH ABSORPTION, [C II] DEFICITS, AND EXTREME LFIR/MH2 RATIOS IN GALAXIES
- 2015
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Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 800:1, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Herschel/PACS observations of 29 local (ultra) luminous infrared galaxies, including both starburst and active galactic nucleus (AGN) dominated sources as diagnosed in the mid-infrared/optical, show that the equivalent width of the absorbing OH 65 mu m.3/2 J = 9/2-7/2 line (Weq(OH65)) with lower level energy Elow 300 K, is anticorrelated with the [Cii] 158 mu m line to far-infrared luminosity ratio, and correlated with the far-infrared luminosity per unit gas mass and with the 60-to-100 mu m far-infrared color. While all sources are in the active LIR/MH2 > 50L /M mode as derived from previous CO line studies, the OH65 absorption shows a bimodal distribution with a discontinuity at LFIR/MH2 100L /M . In the most buried sources, OH65 probes material partially responsible for the silicate 9.7 mu m absorption. Combined with observations of the OH 71 mu m.1/2 J = 7/2-5/2 doublet (Elow 415 K), radiative transfer models characterized by the equivalent dust temperature, Tdust, and the continuum optical depth at 100 mu m, t100, indicate that strong [C ii] 158 mu m deficits are associated with far-IR thick (t100 0.7, NH 1024 cm-2), warm (Tdust 60 K) structures where the OH 65 mu m absorption is produced, most likely in circumnuclear disks/tori/cocoons. With their high LFIR/MH2 ratios and columns, the presence of these structures is expected to give rise to strong [C ii] deficits. Weq(OH65) probes the fraction of infrared luminosity arising from these compact/warm environments, which is 30%-50% in sources with high Weq(OH65). Sources with high Weq(OH65) have surface densities of both LIR and MH2 higher than inferred from the half-light (CO or UV/optical) radius, tracing coherent structures that represent the most buried/active stage of (circum) nuclear starburst-AGN co-evolution.
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| 2. |
- Gonzalez-Alfonso, E., et al.
(författare)
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Molecular Outflows in Local ULIRGs: Energetics from Multitransition OH Analysis
- 2017
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 836:1
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Tidskriftsartikel (refereegranskat)abstract
- 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 mu m) and one or more radiatively excited (at 65 and 84 mu m) lines allows us to model the nuclear gas (. 300 pc) and 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) x 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 active galactic nuclei (AGNs) and nuclear starbursts, as a result of radiation pressure, winds, and supernova remnants. In some sources ( similar to 20%), however, powerful (10(10.5- 11) L circle dot) AGN feedback and (partially) energy-conserving phases are required, with momentum boosts in the range of 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 past similar to 1 Myr. While OH traces the molecular outflows at subkiloparsec 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 of M/SFR = 1-10) from the central galactic cores (a few. x. 100 pc), qualitatively consistent with an ongoing inside-out quenching of star formation. Outflow depletion timescales are
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| 3. |
- Ashby, Nathaniel J. S., et al.
(författare)
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Finding the Right Fit: A Comparison of Process Assumptions Underlying Popular Drift-Diffusion Models
- 2016
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Ingår i: Journal of Experimental Psychology. Learning, Memory and Cognition. - : AMER PSYCHOLOGICAL ASSOC. - 0278-7393 .- 1939-1285. ; 42:12, s. 1982-1993
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Tidskriftsartikel (refereegranskat)abstract
- Recent research makes increasing use of eye-tracking methodologies to generate and test process models. Overall, such research suggests that attention, generally indexed by fixations (gaze duration), plays a critical role in the construction of preference, although the methods used to support this supposition differ substantially. In 2 studies we empirically test prototypical versions of prominent processing assumptions against 1 another and several base models. We find that general evidence accumulation processes provide a good fit to the data. An accumulation process that assumes leakage and temporal variability in evidence weighting (i.e., a primacy effect) fits the aggregate data, both in terms of choices and decision times, and does so across varying types of choices (e.g., charitable giving and hedonic consumption) and numbers of options well. However, when comparing models on the level of the individual, for a majority of participants simpler models capture choice data better. The theoretical and practical implications of these findings are discussed.
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