The interpretation of rotation measures of extragalactic radio sources.
Abstract
The Galactic, intrinsic source, and intergalactic-magnetic-field contributions to the observed rotation measures (RM) of extragalactic radio sources are studied simultaneously in the framework of a simple model in which the observed RM is represented as the sum of these three contributions. A regression method is used to obtain the model parameters as well as information on the magnitude of possible selection and evolutionary effects. The analysis is applied to selected extragalactic radio sources listed in three basic catalogs; it is found that the value of the Galactic contribution is practically independent of redshift and the mass density of the universe, while the intergalactic-magnetic-field contribution is insignificant. The magnitude of the large-scale Galactic magnetic field is estimated to be about 4.5 microgauss, and it is concluded that there is no definite evidence for the existence of a homogeneous intergalactic magnetic field.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 1977
- Bibcode:
- 1977A&A....58..247R
- Keywords:
-
- Astrometry;
- Astronomical Models;
- Extragalactic Radio Sources;
- Quasars;
- Regression Analysis;
- Astronomical Catalogs;
- Intergalactic Media;
- Interstellar Magnetic Fields;
- Magnetic Effects;
- Magnetic Fields;
- Radio Galaxies;
- Astrophysics