The 60 micron to 20 centimeter infrared-to-radio ratio within spiral galaxies

Journal Article · Mon Oct 01 04:00:00 EDT 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/169243· OSTI ID:6315905

Bicay, M D; Helou, G ^[1]

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1. California Institute of Technology, Pasadena (USA)

A detailed comparison is presented of the distribution of 60 micron IR and 20 cm radio continuum emission within 25 galaxies, mostly disk spirals. Local maxima in the thermal IR and nonthermal radio emission are found to be spatially coincident on scales of less than about 0.4 kpc in the nearest sample galaxies. The IR-red disk in normal spirals appears to be characterized by a shorter scale length than that of the radio continuum disk, suggesting that the IR-to-radio ratio should decrease as a function of radius. A model that successfully accounts for the observations is introduced which is based on the assumptions of steady-state star formation activity within the disk on kpc scales and a tight coupling between the origins of the dust-heating radiation and the radio-emitting cosmic-ray electrons. The underlying source is described as an exponential disk. The results also suggest that a random walk process cannot by itself describe the temporal evolution of cosmic rays. 34 refs.

• OSTI ID: 6315905
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 362; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPARATIVE EVALUATIONS
CONFIGURATION
COSMIC ELECTRONS
COSMIC RADIATION
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
FAR INFRARED RADIATION
FERMIONS
GALAXIES
HEATING
INFRARED RADIATION
IONIZING RADIATIONS
LEPTONS
MATHEMATICAL MODELS
PHOTOMETRY
RADIATIONS
RADIOWAVE RADIATION
RANDOMNESS
SATELLITES
SPIRAL CONFIGURATION
STAR EVOLUTION