CGPS Science Project:
Neutral Hydrogen Self-Absorption Features

H I self-absorption (HISA) against background H I emission traces cold atomic gas in the interstellar medium. The high resolution, wide angular coverage, and multiwavelength nature of the CGPS provide a unique opportunity to examine this phenomenon in great detail.

We seek to investigate the physical properties, cloud geometry, structure, Galactic distribution, and phase relations of the HISA material by identifying all such detectable features in the CGPS dataset, analyzing their radiative transfer, mapping their dispositions, and comparing locations and morphologies with other ISM phase tracers, such as CO emission and HIRES dust.

Links are given here to various HISA results:

• 2004 Dec: CGPS Phase I HISA survey paper submitted to ApJ
• 2002 May: HISA, NHIE, and CO (from Edmonton IGPS meeting)
• 2002 May: CASCA poster
• 2002 Jan: AAS poster
• 2001 May: CASCA poster (with additional material from Green Bank IGPS meeting)
• 2001 Jan: AAS poster
• 2000 Jan: AAS poster
• 1999 Dec: HISA Paper I (draft submitted to ApJ)
• 1999 May: MV-MA preliminary census (from Vancouver CGPS meeting)
• 1999 Jan: AAS poster
• 1998 May: Single Dish comparison with other datasets
• 1998 Apr: MW1 features (from Kingston CGPS meeting)

And to CGPS newsletter articles:

• 2005 Apr: CGPS 1 + 2 + VGPS HISA Overview
• 2004 Dec: CGPS HISA Survey Paper
• 2002 Jun: HISA vs. Anti-HISA
• 2001 Jun: Characteristics of HISA Clouds
• 2000 Jun: HISA vs. 13CO
• 2000 Mar: first paper, new census, & new CO observations
• 1999 Jun: preliminary census summary
• 1999 Mar: MVW Velocity Distribution
• 1998 Jun: First Results