The prevalence of FRI radio quasars - AstrophysicsReportar como inadecuado

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Abstract: We present deep, multi-VLA-configuration radio images for a set of 18quasars, having redshifts between 0.36 and 2.5, from the 7C quasar survey.Approximately one quarter of these quasars have FRI-type twin-jet structuresand the remainder are a broad range of wide angle tail, fat double, classicaldouble, core-jet and hybrid sources. These images demonstrate that FRI quasarsare prevalent in the universe, rather than non-existent as had been suggestedin the literature prior to the serendipitous discovery of the first FRI quasara few years ago, the optically powerful -radio quiet- quasar E1821+643. Some ofthe FRI quasars have radio luminosities exceeding the traditional FRI - FRIIbreak luminosity, however we find no evidence for FRII quasars withluminosities significantly below the break. We consider whether the existenceof such high luminosity FRI structures is due to the increasingly inhomogeneousenvironments in the higher redshift universe.

Autor: Ian Heywood, Katherine M. Blundell, Steve Rawlings


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