Notes:

FR I radio galaxy = Fanaroff-Riley type I radio galaxy. These objects usually have prominent smooth continuous two-sided jets running into large-scale lobes structures which appear edge-darkened.
FR II radio galaxy = Fanaroff-Riley type II radio galaxy. These objects tend to have edge-brightened large-scale structures with bright outer hotspots.
The FR I / FR II division also appears in the luminosity of these sources, with FR I sources being less luminous and FR II more luminous than P(178MHz)=2*10²⁶ WHz^-1 (Fanaroff & Riley 1974).

BLO = BL Lacertae object. (Originally radio-loud) objects with featureless continuum spectrum (very weak emission lines). They usually show strong polarization and rapid variability. The archetype BL Lacertae is a source which was first suspected of being a variable star in our Galaxy.

QSO = quasar.

HPQ = a highly polarized quasar, with the otical polarization p>3%.

LPQ = a low-polarized quasar, with the otical polarization p<3%.

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Last update: 2001-07-23 / mtt