Opacity broadening and interpretation of suprathermal CO linewidths: Macroscopic Turbulence and Tangled Molecular Clouds

  title={Opacity broadening and interpretation of suprathermal CO linewidths: Macroscopic Turbulence and Tangled Molecular Clouds},
  author={{\'A}lvaro Hacar and Jo{\~a}o Alves and Andreas Burkert and Paul. F. Goldsmith},
  journal={arXiv: Astrophysics of Galaxies},
(Abridged) Many of the observed CO line profiles exhibit broad linewidths that greatly exceed the thermal broadening expected within molecular clouds. These suprathermal CO linewidths are assumed to be originated from the presence of unresolved supersonic motions inside clouds. Typically overlooked in the literature, in this paper we aim to quantify the impact of the opacity broadening effects on the current interpretation of the CO suprathermal line profiles. Without any additional… 
Relations between Molecular Cloud Structure Sizes and Line Widths in the Large Magellanic Cloud
We present a comparative study of the size-line width relation for substructures within six molecular clouds in the Large Magellanic Cloud (LMC) mapped with the Atacama Large Millimeter/submillimeter
Molecular Gas toward Supernova Remnant Cassiopeia A
We mapped 12CO J=1-0, 12CO J=2-1, 13CO J=1-0, and 13CO J=2-1 lines toward supernova remnant (SNR) Cassiopeia A with the IRAM 30m telescope. The molecular clouds (MCs) along the line of sight of Cas A
ALMA Observations of NGC 6334S. I. Forming Massive Stars and Clusters in Subsonic and Transonic Filamentary Clouds
We present Atacama Large Millimeter/submillimeter Array (ALMA) and Karl G. Jansky Very Large Array (JVLA) observations of the massive infrared dark cloud NGC 6334S (also known as IRDC G350.56+0.44),
CO Emission Delineating the Interface between the Milky Way Nuclear Wind Cavity and the Gaseous Disk
Based on the MWISP survey, we study high-z CO emission toward the tangent points, in which the distances of the molecular clouds (MCs) are well determined. In the region of l = 12°–26° and ∣b∣ ≲
ALMA Observations of a Quiescent Molecular Cloud in the Large Magellanic Cloud
We present high-resolution (sub-parsec) observations of a giant molecular cloud in the nearest star-forming galaxy, the Large Magellanic Cloud. ALMA Band 6 observations trace the bulk of the
Understanding biases in measurements of molecular cloud kinematics using line emission
Molecular line observations using a variety of tracers are often used to investigate the kinematic structure of molecular clouds. However, measurements of cloud velocity dispersions with different
Striations in molecular clouds: streamers or MHD waves?
Dust continuum and molecular observations of the low column density parts of molecular clouds have revealed the presence of elongated structures which appear to be well aligned with the magnetic
Multicomponent Kinematics in a Massive Filamentary Infrared Dark Cloud
To probe the initial conditions for high-mass star and cluster formation, we investigate the properties of dense filaments within the infrared dark cloud G035.39-00.33 (IRDC G035.39) in a combined
A search for evidence of small-scale inhomogeneities in dense cores from line profile analysis
  • L. Pirogov
  • Physics
    Research in Astronomy and Astrophysics
  • 2018
In order to search for intensity fluctuations on the HCN(1--0) and HCO$^+$(1--0) line profiles which could arise due to possible small-scale inhomogeneous structure long-time observations of the S140
Spatially associated clump populations in Rosette from CO and dust maps
Spatial association of clumps from different tracers turns out to be a valuable tool to determine the physical properties of molecular clouds. It provides a reliable estimate for the $X$-factors,


Opacity broadening of 13 co linewidths and its effect on the variance-sonic mach number relation
We study how the estimation of the sonic Mach number (M{sub s} ) from {sup 13}CO linewidths relates to the actual three-dimensional sonic Mach number. For this purpose we analyze MHD simulations that
The photodissociation and chemistry of interstellar CO
Recent work on the vacuum UV absorption spectrum of CO to the description of the photodissociation of interstellar CO and its principal isotopic varieties is discussed. The effects of line
The relationship between carbon monoxide abundance and visual extinction in interstellar clouds.
Carbon monoxide column densities are compared to visual extinctions toward field stars in the rho Oph and Taurus molecular cloud complexes. The relationship of C/sup 18/O column density to A/sub v/
Diffuse Molecular Cloud Densities from UV Measurements of CO Absorption
We use UV measurements of interstellar CO toward nearby stars to calculate the density in the diffuse molecular clouds containing the molecules responsible for the observed absorption. Chemical
H I Narrow Self-Absorption in Dark Clouds
We have used the Arecibo telescope to carry out a survey of 31 dark clouds in the Taurus/Perseus region for narrow absorption features in H I (21 cm) and OH (1667 and 1665 MHz) emission. We detected
The Musca cloud: A 6 pc-long velocity-coherent, sonic filament
Filaments play a central role in the molecular clouds' evolution, but their internal dynamical properties remain poorly characterized. To further explore the physical state of these structures, we
The Resolved Properties of Extragalactic Giant Molecular Clouds
Abstract Giant molecular clouds (GMCs) are the major reservoirs of molecular gas in galaxies, and the starting point for star formation. As such, their properties play a key role in setting the
CO(J = 1-0) line emission from giant molecular clouds
Numerical models of the (C-12)O (J = 1-0) line emission from giant molecular clouds (GMCs) have been constructed. Line profiles are presented for both microturbulent and macroturbulent clouds. The
13CO filaments in the Taurus molecular cloud
We have carried out a search for filamentary structures in the Taurus molecular cloud using $\rm^{13}CO$ line emission data from the FCRAO survey of $\rm \sim100 \, deg^2$. We have used the
Molecular line mapping of the giant molecular cloud associated with RCW 106 - II. Column density and dynamical state of the clumps
We present a fully sampled C 18 O (1-0) map towards the southern giant molecular cloud (GMC) associated with the H II region RCW 106, and use it in combination with previous 1 3 CO (1-0) mapping to