Molecular outflows in local galaxies: Method comparison and a role of intermittent AGN driving
Journal article, 2020
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.
galaxies: active
galaxies: kinematics and dynamics
galaxies: ISM
Author
D. Lutz
Max Planck Society
E. Sturm
Max Planck Society
A. Janssen
Max Planck Society
Nederlandse Onderzoekschool voor Astronomie (NOVA)
S. Veilleux
Space Telescope Science Institute (STScI)
University of Cambridge
University of Maryland
Susanne Aalto
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
C. Cicone
Istituto nazionale di astrofisica (INAF)
University of Oslo
A. Contursi
Institut de Radioastronomie Millimétrique (IRAM)
Max Planck Society
R. I. Davies
Max Planck Society
C. Feruglio
Istituto nazionale di astrofisica (INAF)
J. Fischer
George Mason University
A. Fluetsch
University of Cambridge
S. Garcia-Burillo
Spanish National Observatory (OAN)
R. Genzel
Max Planck Society
E. Gonzalez-Alfonso
University of Alcalá
J. Gracia-Carpio
Max Planck Society
R. Herrera-Camus
University of Concepcion
Max Planck Society
R. Maiolino
University of Cambridge
A. Schruba
Max Planck Society
T. Shimizu
Max Planck Society
A. Sternberg
Tel Aviv University
L. J. Tacconi
Max Planck Society
A. Weiss
Max Planck Society
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 633 A134Subject Categories
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/201936803