The Extraordinary Radio Source 3C 442
Abstract
We have studied the distinctive system 3C 442 with VLA at 6, 20, and 90 cm. This source is associated with two galaxies, NGC 7236/7237. The image of the radio source shows a mass of filaments and diffuse emission surrounding the two galaxies. A weak resolved radio core lies at the position of NGC 7237, and two arcs of steep-spectrum radio emission cross the region containing the optical galaxies, but no opaque radio core or head-tail jet structures are found, as is usually the case for radio galaxies of similar radio luminosity. The spectral index over the entire system is roughly constant. Typically, α ~ 1.1 with some regions differing by +/- 0.2 from this value. The properties of this radio source are similar to a few other well- studied systems, all of which are associated with binary galaxies and some of which also show evidence for mergers. We propose that the unusual morphology of 3C 442 is due to a galactic merger in progress. The high ellipticity of the cluster of galaxies in which NGC 7236/7237 are imbedded suggests that they may be the central galaxies in a pair of merging clusters. We suggest that the collimated gas was produced by a previously existing radio galaxy whose radio source was disrupted by the gravitational influence of the merger on the gas surrounding the source. The large-scale structure of 3C 442 is the result of these electrons interacting with the hot gas of the disturbed intracluster medium, and thereby becoming trapped in the debris of the merger.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1991
- DOI:
- 10.1086/170698
- Bibcode:
- 1991ApJ...382..108C
- Keywords:
-
- Interacting Galaxies;
- Radio Galaxies;
- Galactic Clusters;
- Radio Emission;
- Very Large Array (Vla);
- Astrophysics;
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 7236;
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 7237;
- GALAXIES: INTERACTIONS;
- RADIO SOURCES: GALAXIES