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Compact Cosmos

11 10 ACTIVEGALAXIES and quasar questions With ingenious devices scanning the heavens in spectrums beyond the visible, many marvels have been revealed in recent years, and some of the most awesome are the active galaxies. Spewing jets of matter many lightyears long from a relatively small nucleus, radio galaxies are brightly lit in the xray and radio bands even though they may be optically comparatively dim. Seyfert galaxies are spinning discs with intensely active nuclei. Slightly less bright than Seyferts,elliptical Ngalaxieshave nuclei that vary in intensity. A subspecies, BL Lacertae BL Lac objects, have nuclei that are even brighter and more wildly fluctuating. Here it seems we are looking headon,directly into a jet. Quasars quasistellar radio sourcesare a hundred to a thousand times brighter than normal galaxies and emit vast quantities of radiation opposite top. It is thought that they are the bright hearts of active galaxies,powered by supermassive black holes. With very high redshifts indeed, quasars are assumed to be incredibly distant young galaxies from a much earlier age of the universe, but a number of quasars, often in pairs with similar redshifts, look like they may have been ejected from other active galaxies lower opposite. They may be recently born galaxies. Objectors point to the quasarsgreater redshifts and infer they must be farther away and,so,unrelated or gravitationally lensed. If the redshifts are anomalous it raises the possibility that our distance estimates may be somewhat inaccurate and that perhaps light could behave differently in high energy zones.
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