We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
Published online by Cambridge University Press: 04 August 2010
High resolution 21 cm observations of the Ursa Major cirrus revealed highly filamentary structures down to the 0.03 pc resolution. These filaments, still present in the line centroid map, show multi-Gaussian components and seem to be associated with high vorticity regions. Probability density functions of line centroid increments and structure functions were computed on the line centroid field, providing strong evidences for the presence of turbulence in the atomic gas.
Introduction
Many statistical studies of the density and velocity structure of dense interstellar matter have been done on molecular clouds where turbulence is seen as a significant support against gravitational collapse that leads to star formation. Less attention has been devoted to turbulence in the Galactic atomic gas (HI). The cold atomic component (T ∼ 100 K, n ∼ 100 cm−3), alike molecular gas, is characterized by multiscale self-similar structures and non-thermal linewidths.
A detailed and quantitative study of the turbulence and kinematics of HI clouds has never been done. Here we present a preliminary analysis of this kind based on high resolution 21 cm observations of an HI cloud located in the Ursa Major constellation. To characterize the turbulent state of the atomic gas, a statistical analysis of the line centroid field has been done. We have computed probability density functions of line centroid increments and structure functions.
HI Observations
The Ursa Major cirrus (α(2000) = 9h36m, δ(2000) = 70°20′) has been observed with the Penticton interferometer.
To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.
