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: ISM

galaxies: active

galaxies: kinematics and dynamics


D. Lutz

Max Planck Society

E. Sturm

Max Planck Society

A. Janssen

Nederlandse Onderzoekschool voor Astronomie (NOVA)

Max Planck Society

S. Veilleux

University of Maryland

University of Cambridge

Space Telescope Science Institute (STScI)

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

Max Planck Society

University of Concepcion

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 A134

Subject Categories

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

Other Physics Topics



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