2016/04/01 by A. W. Janssen, A. Janssen, N. Christopher +18
Chemistry · Physics and Astronomy · #Absorption (acoustics) #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Star Formation Studies #Atomic and Molecular Physics #Full width at half maximum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Geometry #Inflow #Infrared #Lambda #Line (geometry) #Optics #Outflow #Physics #Redshift #Spectral line #Spectroscopy and Laser Applications #TRACER #astro-ph.GA
paper · pdf · doi:10.3847/0004-637x/822/1/43
accepted for publication in ApJ
arxiv created 2016/04/01 · openalex publication_date 2016/05/01 · arxiv updated 2016/05/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/15
ABSTRACT We report a tentative correlation between the outflow characteristics derived from OH absorption at 119 μ m and [C ii ] emission at 158 μ m in a sample of 22 local and bright ultraluminous infrared galaxies (ULIRGs). For this sample, we investigate whether [C ii ] broad wings are a good tracer of molecular outflows, and how the two tracers are connected. Fourteen objects in our sample have a broad wing component as traced by [C ii ], and all of these also show OH119 absorption indicative of an outflow (in one case an inflow). The other eight cases, where no broad [C ii ] component was found, are predominantly objects with no OH outflow or a low-velocity (≤100 km s −1 ) OH outflow. The FWHM of the broad [C ii ] component shows a trend with the OH119 blueshifted velocity, although with significant scatter. Moreover, and despite large uncertainties, the outflow masses derived from OH and broad [C ii ] show a 1:1 relation. The main conclusion is therefore that broad [C ii ] wings can be used to trace molecular outflows. This may be particularly relevant at high redshift, where the usual tracers of molecular gas (like low-J CO lines) become hard to observe. Additionally, observations of blueshifted Na i D λλ 5890, 5896 absorption are available for 10 of our sources. Outflow velocities of Na i D show a trend with OH velocity and broad [C ii ] FWHM. These observations suggest that the atomic and molecular gas phases of the outflow are connected.