paper

Optical integral field spectroscopy of the extended line emission around six radio-loud quasars

arXiv:astro-ph/9912306 · doi:10.1046/j.1365-8711.2000.03290.x

Abstract

We present integral field spectroscopy of a small sample of radio-loud quasars at intermediate redshift (0.26<z<0.60), most of which are associated with large radio sources. All have oxygen line emission extended over tens of kiloparcsecs, and these nebulae display a diverse range in both morphology and kinematic behaviour. Two quasars show 'plumes' of extended line emission, two show a clumpy structure and a further one shows a smooth distribution. There is no clear pattern with regard to the distribution of the ionized gas in relation to the radio source axis; the extended emission-line regions are found both parallel and perpendicular - and also totally unrelated to - the radio axis. The velocity structure of the ionized gas ranges from essentially static to apparent smooth rotation, and in two cases, show a clear association with the radio source. Given the disparity in properties, the nebulae all show a surprisingly similar ionization state, as measured by the extended lines of [OII] and [OIII]. Assuming the gas is ionized by at least the nearby quasar nucleus, we use the emission line ratios to infer a pressure in the ionized gas; in all cases we find it to be at high pressure, suggesting confinement by an external (probably intracluster) medium.

14 pages, 18 figures, 10 of which are presented separately; accepted for publication in MNRAS

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