With this grant Dr. Carl Heiles will continue a research program which spans many subareas under the heading of interstellar matter. The proposed research will be directed toward advancing our understanding of the morphology of the interstellar neutral atomic hydrogen in the Galaxy, the nature of the interstellar magnetic field, and the cosmic abundance of deuterium. Dr. Heiles' studies are carried out primarily through observations of spectral lines of atoms and molecules at radio wavelengths. The study of the morphology of atomic hydrogen in the Galaxy may provide important information about those cosmic processes that shape the structure of the interstellar medium, such as supernova explosions and stellar winds. The basic magnetic field studies are significant for understanding such interstellar processes as star formation, the support of gas in the Galactic halo, and the heating of the interstellar medium via various types of hydromagnetic waves. Finally, a good determination of the abundance of deuterium in a variety of astronomical sites is fundamental to cosmology.
