Centroid velocity statistics of molecular clouds

We compute structure functions and Fourier spectra of 2D centroid velocity maps in order to study the gas dynamics of typical molecular clouds in numerical simulations. We account for a simplified treatment of time-dependent chemistry and the non-isothermal nature of the gas and use a 3D radiative t...

Full description

Saved in:
Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 2015-02, Vol.446 (4), p.3777-3777
Main Authors: Bertram, Erik, Konstandin, Lukas, Shetty, Rahul, Glover, Simon C O, Klessen, Ralf S
Format: Article
Language:English
Subjects:
Astronomy
Carbon monoxide
Centroids
Computer simulation
Density
Fourier analysis
Mathematical models
Simulation
Slopes
Spectra
Star & galaxy formation
Velocity
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We compute structure functions and Fourier spectra of 2D centroid velocity maps in order to study the gas dynamics of typical molecular clouds in numerical simulations. We account for a simplified treatment of time-dependent chemistry and the non-isothermal nature of the gas and use a 3D radiative transfer tool to model the CO line emission in a post-processing step. We perform simulations using three different initial mean number densities of n0 = 30, 100 and 300 cm... to span a range of typical values for dense gas clouds in the solar neighbourhood. We compute slopes of the centroid velocity increment structure functions (CVISF) and of Fourier spectra for different chemical components: the total density, H2 number density, 12CO number density as well as the integrated intensity of ...CO (J = 1 ... 0) and ...CO (J = 1 ... 0). We show that optical depth effects can significantly affect the slopes derived for the CVISF, which also leads to different scaling properties for the Fourier spectra. The slopes of CVISF and Fourier spectra for H2 are significantly steeper than those for the different CO tracers, independent of the density and the numerical resolution. This is due to the larger space-filling factor of H2 as it is better able to self-shield in diffuse regions, leading to a larger fractal co-dimension compared to CO. (ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/stu2372