Obtaining Statistics of Turbulent Velocity from Astrophysical Spectral Line Data
arXiv:astro-ph/0408176 · doi:10.1007/978-1-4020-2862-5_50
Abstract
Turbulence is a crucial component of dynamics of astrophysical fluids dynamics, including those of ISM, clusters of galaxies and circumstellar regions. Doppler shifted spectral lines provide a unique source of information on turbulent velocities. We discuss Velocity-Channel Analysis (VCA) and its offspring Velocity Coordinate Spectrum (VCS) that are based on the analytical description of the spectral line statistics. Those techniques are well suited for studies of supersonic turbulence. We stress that a great advantage of VCS is that it does not necessary require good spatial resolution. Addressing the studies of mildly supersonic and subsonic turbulence we discuss the criterion that allows to determine whether a traditional tool for such a research, namely, Velocity Centroids are dominated by density or velocity. We briefly discuss the use of higher order correlations as the means to study intermittency of turbulence. We discuss observational data available and prospects of the field.
12 pages, Invited Talk, Penetrating Bars Through Masks of Cosmic Dust, Pilanesberg National Park, South Afrika, 7 June-12 June 2004
References in corpus (8)
- Compressible Magnetohydrodynamic Turbulence: mode coupling, scaling relations, anisotropy, new regime and astrophysical implications
- Star Formation from Galaxies to Globules
- Turbulence in Clusters of Galaxies and X-Ray Line Profiles
- Structure Function Scaling in the Taurus and Perseus Molecular Cloud Complexes
- Ordinary and Viscosity-Damped MHD Turbulence
- Statistics of Velocity from Spectral Data: Modified Velocity Centroids
- Velocity statistics from spectral line data: effects of density-velocity correlations, magnetic field, and shear
- Modification of Projected Velocity Power Spectra by Density Inhomogeneities in Compressible Supersonic Turbulence