Automatic Shell Detection in CGPS Data
Abstract
A numerical code aiming at the automatic detection of spherical expanding HI shells in radio data-cubes is presented. The following five shell parameters are allowed to vary within a specified range: angular radius, expansion velocity and three center coordinates (galactic coordinates l and b, and systemic radial velocity V). We discuss several factors which can reduce the sensitivity of the shell detection: the presence of noise (both instrumental and "structural"), the fragmentation and asphericity of the shell and the inhomogeneity of the background and/or foreground emission. The code is tested on four objects: two HII regions and two early B stars. We use HI data from the Canadian Galactic Plane Survey. In all four cases the evidence for an expanding HI shell is found.
Cite
@article{arxiv.astro-ph/0010140,
title = {Automatic Shell Detection in CGPS Data},
author = {Sergey Mashchenko and Nicole St-Louis},
journal= {arXiv preprint arXiv:astro-ph/0010140},
year = {2007}
}
Comments
6 pages, 4 figures; to appear in the proceedings of the conference "Interacting Winds from Massive Stars" (ASP Conference Series), eds. A. F. J. Moffat, and N. St-Louis