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- Lutz, D., et al.
(författare)
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Molecular outflows in local galaxies: Method comparison and a role of intermittent AGN driving
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 633
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Tidskriftsartikel (refereegranskat)abstract
- We report new detections and limits from a NOEMA and ALMA CO(1-0) search for molecular outflows in 13 local galaxies with high far-infrared surface brightness, and combine these with local universe CO outflow results from the literature. The CO line ratios and spatial outflow structure of our targets provide some constraints on the conversion steps from observables to physical quantities such as molecular mass outflow rates. Where available, ratios between outflow emission in higher J CO transitions and in CO(1-0) are typically consistent with excitation R-i1 less than or similar to 1. However, for IRAS 13120 5453, R-31 = 2.10 +/- 0.29 indicates optically thin CO in the outflow. Like much of the outflow literature, we use ff CO(1 0) = 0.8, and we present arguments for using C = 1 in deriving molecular mass outflow rates. (M)over dot(out) = CM(out)v(out)/R-out. We compare the two main methods for molecular outflow detection: CO millimeter interferometry and Herschel OH-based spectroscopic outflow searches. For 26 sources studied with both methods, we find an 80% agreement in detecting vout & 150 km s 1 outflows, and non-matches can be plausibly ascribed to outflow geometry and signal-to-noise ratio. For a published sample of 12 bright ultraluminous infrared galaxies with detailed OH-based outflow modeling, CO outflows are detected in all but one. Outflow masses, velocities, and sizes for these 11 sources agree well between the two methods, and modest remaining di fferences may relate to the di fferent but overlapping regions sampled by CO emission and OH absorption. Outflow properties correlate better with active galactic nucleus (AGN) luminosity and with bolometric luminosity than with far-infrared surface brightness. The most massive outflows are found for systems with current AGN activity, but significant outflows in nonAGN systems must relate to star formation or to AGN activity in the recent past. We report scaling relations for the increase of outflow mass, rate, momentum rate, and kinetic power with bolometric luminosity. Short flow times of similar to 10(6) yr and some sources with resolved multiple outflow episodes support a role of intermittent driving, likely by AGNs.
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| 2. |
- Guerrero-Casado, José, et al.
(författare)
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Assessment of the suitability of latrine counts as an indirect method by which to estimate the abundance of European rabbit populations at high and low abundance
- 2020
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Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 66:1
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Tidskriftsartikel (refereegranskat)abstract
- Monitoring European rabbit (Oryctolagus cuniculus) populations using suitable methods is crucial, especially in those areas in which endangered predators remain and rabbits occur at low densities. We first counted the number of rabbits, the number of scattered pellets, and the number of latrines counted within 16 plots established in areas of low rabbit density, showing that the number of rabbits counted inside the plots was more closely correlated with the number of pellets counted than with the number of latrines. In addition, no latrines were found in 8 plots. In 53 walking transects, the number of pellets m−2 and the number of latrines km−1 had a positive relationship, but no significant correlation was obtained between the two methods when only the transects with a low rabbit abundance were selected. These results suggest that although counting latrines can be useful to compare areas with different abundances, it may underestimate rabbit abundance at low abundances where counting scattered pellets is, therefore, the most accurate alternative. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
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