Galactic gamma-ray observations and galactic structure

Technical Report · Sat Nov 01 04:00:00 EST 1975

OSTI ID:7245361

Stecker, F W

Recent observations of gamma rays originating in the galactic disk together with radio observations support an emerging picture of the overall structure of our galaxy with higher interstellar gas densities and star formation rates in a region which corresponds to that of the inner arms. The emerging picture is one where molecular clouds make up the dominant constituent of the interstellar gas in the inner galaxy, and play a key role in accounting for the gamma rays and phenomena associated with the production of young stars and other population-1 objects. In this picture, cosmic rays are associated with supernovae and are primarily of galactic origin. These newly observed phenomena can be understood as consequences of the density wave theories of spiral structure. Based on these new developments, the suggestion is made that a new galactic population class, Population O, be added to the standard Populations 1 and 2 in order to recognize important differences in dynamics and distribution between diffuse galactic H1 and interstellar molecular clouds. (auth)

• Research Organization: National Aeronautics and Space Administration, Greenbelt, Md. (USA). Goddard Space Flight Center
• OSTI ID: 7245361
• Report Number(s): N-76-12933; NASA-TM-X-71015; X-602-75-297
• Country of Publication: United States
• Language: English

Related Subjects

640101 -- Astrophysics & Cosmology-- Cosmic Radiation
640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC GASES
COSMIC PHOTONS
COSMIC RADIATION
COSMIC RAY SOURCES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
FLUIDS
GALACTIC EVOLUTION
GALAXIES
GAMMA RADIATION
GASES
INTERSTELLAR SPACE
IONIZING RADIATIONS
MASSLESS PARTICLES
MILKY WAY
MOLECULES
ORIGIN
PHOTONS
RADIATIONS
SPACE
STAR EVOLUTION
STARS
STRUCTURAL MODELS
SUPERNOVAE