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Title: Weakly barred early-type ringed galaxies. III. The remarkable outer-ringed S0+ galaxy NGC 7020

The southern S0+ galaxy NGC 7020 presents an unusual morphology: it includes a very regular outer ring which is completely detached and which envelops an inner ring/lens zone with an exotic hexagonal shape. The ring has a high contrast compared with those usually observed in barred galaxies, yet NGC 7020 is not obviously barred. In this paper, the structure of this galaxy is studied by means of UBVRI CCD surface photometry. The photometry reveals a complex system and shows that most of the recent star formation in the galaxy has taken place in the outer ring. Two bright knots are found on the major axis of the hexagonal zone that appear to be true enhancements of old stars rather than young associations. Between these knots and the bulge there are dips in the surface brightness and a clear zone of rectangular isophotes. 56 refs.
Authors:
 [1]
  1. (Alabama Univ., Tuscaloosa (USA))
Publication Date:
OSTI Identifier:
6697053
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; (USA); Journal Volume: 356
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; GALAXIES; MORPHOLOGY; BRIGHTNESS; CHARGE-COUPLED DEVICES; GALACTIC EVOLUTION; PHOTOMETRY; SPIRAL CONFIGURATION; STAR EVOLUTION; CONFIGURATION; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; SEMICONDUCTOR DEVICES 640105* -- Astrophysics & Cosmology-- Galaxies