Infrared Background Starlight: Observations and Galaxy Models

Abstract

The near-infrared region of the spectrum is a particularly advantageous window for observing the distribution of old, evolved stars in the galactic disk and bulge. These stars are important because they provide an excellent tracer of the overall stellar mass distribution. At shorter wavelengths extinction is a serious problem, and at longer wavelengths the flux is dominated by dust emission. A summary of the large-scale diffuse near-infrared observations of the Galaxy is presented, as is a summary of the results obtained from these data on the structure of the galactic disk and bulge. The importance of combining CO and near-infrared maps of similar resolution to determine a three-dimensional model of galactic extinction is demonstrated. The Spacelab-2 Infrared Telescope (IRT) data are used in conjunction with a proposed galactic model to make preliminary measurements of the global scale parameters of the Galaxy.