The galactic halo question: new size constraints from galactic gamma-ray data

Technical Report · Tue Mar 01 04:00:00 EST 1977

OSTI ID:7277824

Stecker, F W; Jones, F C

The SAS-2 gamma-ray data are analyzed with use of recent CO line emission and other data for determining the large-scale distribution of galactic gas. A nonuniform distribution of cosmic rays in the galaxy is implied. This fact rules out large trapping halo models and extragalactic origin models. Detailed models of diffusion halos of various sizes perpendicular to the galactic plane are considered. In such models, the scale perpendicular to the plane has a strong effect in determining the radial distribution of cosmic rays. Such radial distributions are calculated for cylindrical coordinate models. The implied gamma-ray longitude distributions are then calculated and compared with the SAS-2 data for goodness-of-fit. If the sources are supernova remnants or pulsars, cosmic ray nucleon halo models with scale heights greater than 3 kpc are found to provide a poor fit to the gamma-ray longitude data (probability of 6% or less). Thin halo, or source dominated diffusion models are found to provide a good fit to the gamma-ray data, with an upper limit scale height of approximately 3 kpc.

• Research Organization: National Aeronautics and Space Administration, Greenbelt, Md. (USA). Goddard Space Flight Center
• OSTI ID: 7277824
• Report Number(s): N-77-22039; NASA-TM-X-71281; X-602-77-73
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC GASES
COSMIC RADIATION
DISTRIBUTION
ELECTROMAGNETIC RADIATION
FLUIDS
GALACTIC EVOLUTION
GALAXIES
GAMMA RADIATION
GASES
IONIZING RADIATIONS
MILKY WAY
RADIATIONS
SPATIAL DISTRIBUTION
STRUCTURAL MODELS