Titre du document

Opaque Radio Sources near the Galactic Equator

Lien vers le document
Nom du Corpus

AstroConcepts

Auteur(s)
  • D. G. MACDONELL 1
  • A. H. BRIDLE 1
Affiliation(s)
  • Astronomy Group, Department of Physics, Queen's University at Kingston, Ontario, Canada.
Résumé

MANY recent studies18 of the continuum spectra of discrete radio sources have provided examples of sources with opaque microwave spectra, in which the flux density has a maximum at a frequency greater than 3 GHz. At least two classes of object have such spectra: compact extragalactic sources, frequently identified3,6,9 with quasi-stellar objects or nuclei of galaxies, and galactic HII regions with high electron densities1. The extragalactic objects are thought to be sources of synchrotron radiation within which the relativistic plasma is opaque at microwave frequencies; some exhibit radio variability which can be explained by an expanding optically thick synchrotron source10. The galactic sources are thought to be optically thick emitters of bremsstrahlung radiation; a nonthermal mechanism11 has also been proposed for these objects. The source VRO 42.22.01 (BL Lac) may be an example of a third class characterized by rapid microwave variability. It is uncertain whether this object is a star with a faint diffuse envelope2 or an extragalactic source for which the line of sight is coincidentally close to the galactic plane.

Langue(s) du document
Indéterminé
Année de publication
1970
Revue

Nature

Éditeur
Nature
Type de publication
journal
Type de document
other
Présence de XML structuré
Oui
Version de PDF
1.4
Score de qualité du texte
4.085
Nom du concept
  • Beta Lacertae object
Catégories Science-Metrix
  • 1 - general ; 2 - general science & technology ; 3 - general science & technology
Catégories Inist
  • 1 - sciences appliquees, technologies et medecines ; 2 - sciences exactes et technologie ; 3 - terre, ocean, espace ; 4 - astronomie
Catégories Scopus
  • 1 - General ; 2 - Multidisciplinary ; 3 - Multidisciplinary
Catégories WoS
  • 1 - science ; 2 - multidisciplinary sciences
Identifiant ISTEX
E7E19845B81E57315A661DB23DD6FA1D0F8B9BBF
ark:/67375/GT4-Q0W83F28-R
Powered by Lodex 9.4.5