An imaging and spectroscopic study of low and intermediate power radio galaxies

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6101773

Ebneter, K A

A search for features (departures from elliptical symmetry) was conducted in a sample of 85 nearby, low, and intermediate power radio galaxies selected from the B2 and 3CR catalogs, and in a comparison sample of 159 optically-selected, early-type galaxies. Charge coupled device (CCD) images of the galaxies were processed using a technique which involves division by a purely elliptical model image, constructed from the best fit surface photometry profiles for a given object. In addition, CCD spectra were obtained of approximately 2/3 of the galaxies in the radio sample, to investigate the stellar populations found in those galaxies. With a small number of exceptions, the radio galaxies were found to have integrated absorption line spectra which are indistinguishable from those of normal, giant elliptical galaxies. The three exceptions show strong Balmer absorption features suggestive of a relatively young stellar population. Radio-loud ellipticals were found to show higher rates of isophotal disturbances than radio-quiet ellipticals. In addition, radio-loud ellipticals in low galaxy density environments had a higher incidence of high-surface-brightness isophotal disturbances and strong nuclear emission lines than those in high galaxy density environments. The evidence suggests that there are two classes of radio galaxies which are distinguished primarily by the local galaxy density of their environment. Class A galaxies are found in regions of low galaxy density; and Class B galaxies are found in regions of high galaxy density. The possible reasons for this distinction between the two classes, and the influence of galactic mergers on the evolution of radio sources, are discussed.

• Research Organization: California Univ., Berkeley, CA (USA)
• OSTI ID: 6101773
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DATA
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
EXPERIMENTAL DATA
GALACTIC EVOLUTION
GALAXIES
INFORMATION
NUMERICAL DATA
RADIATIONS
RADIOWAVE RADIATION
SPECTRA
STARS