Interpretation of deep counts of radio sources

Journal Article · Wed Jul 01 00:00:00 EDT 1987 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/184928· OSTI ID:6086067

Danese, L; Franceschini, A; Toffolatti, L; De zotti, G

A new determination of the local radio luminosity function of galaxies allows it to be concluded that unevolving low-luminosity sources cannot account for the observed flattening of the normalized differential source counts below mJy levels. Nor can this feature be produced by the evolving populations that dominate the counts at higher flux densities. The local radio luminosities of spiral galaxies are too low to contribute significantly to the counts above 1 mJy, even in the presence of evolution consistent with the observational constraints; thus the blue galaxy population observed by Kron, Koo, and Windhorst (1985) up to greater than or equal to 10 mJy can hardly be identified with normal spiral galaxies. On the other hand, it is shown that evolving starburst/interacting galaxies can easily account for all the data available so far. The inferred evolution time scale (about 20-25 percent of the Hubble time) is within the expected range for gas consumption in starburst galaxies. 36 references.

• Research Organization: Padova Universita, Italy; Osservatorio Astronomico, Padua, Italy
• OSTI ID: 6086067
• Journal Information: Astrophys. J.; (United States), Vol. 318
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
RADIO GALAXIES
GALACTIC EVOLUTION
RADIOWAVE RADIATION
LUMINOSITY
RADIANT FLUX DENSITY
SPECTROSCOPY
SPIRAL CONFIGURATION
STAR EVOLUTION
CONFIGURATION
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
FLUX DENSITY
GALAXIES
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
640105* - Astrophysics & Cosmology- Galaxies