A study of FRII radio galaxies with $z \lt 0.15$ – I. High-resolution maps of eight sources at 3.6 cm

Black, A. R. S.; Baum, Stefi A.; Leahy, J. P.; Perley, R. A.; Riley, J. M.; Scheuer, P. A. G.

doi:10.1093/mnras/256.2.186

Cited by 133 publications

(90 citation statements)

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“…¿From the radio contours, the northern jet certainly appears to have resumed its advance recently, after successfully boring its way through a (hypothetical) shell which has caused a prolonged interruption of the jet that has quite plausibly resulted in the radio wing extending to the east. Surviving evidence for the interruption of the jet in the past is seen in the form of the compact radio peak (N3) precisely at the point of the jet/shell interaction, which can be seen in this case thanks to the sub-arc second resolution of the VLA map by Black et al (1992). Such high quality maps are, unfortunately, not available for most XRGs so the signatures of jet/shell interactions are usually less clear as it is the case for nearby radio galaxies such as 3C 433 and Cen A.…”

Section: A Jet-shell Interaction Model For Xrgsmentioning

confidence: 93%

On the origin of X-shaped radio galaxies

Gopal-Krishna

Biermann

Gergely

et al. 2012

Res. Astron. Astrophys.

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After a brief, critical review of the leading explanations proposed for the small but important subset of radio galaxies showing an X-shaped morphology (XRGs) we propose a generalized model, based on the jet-shell interaction and spin-flip hypotheses. The most popular scenarios for this intriguing phenomenon invoke either hydrodynamical backflows and over-pressured cocoons or rapid jet reorientations, presumably from the spin-flips of central engines following the mergers of pairs of galaxies, each of which contains a supermassive black hole (SMBH). We confront these models with a number of key observations and thus argue that none of the models is capable of explaining the entire range of salient observational properties of XRGs, although some of the arguments raised in the literature against the spin-flip scenario are probably not tenable. We then propose here a new scenario which also involves galactic mergers but would allow the spin of the central engine to maintain its direction. Motivated by the detailed multi-band observations of the nearest radio galaxy, Centaurus A, this new model emphasizes the role of interactions between the jets and the shells of stars and gas that form and rotate around the merged galaxy and can cause temporary deflections of the jets, occasionally giving rise to an X-shaped radio structure. Although each of the models is likely to be relevant to a subset of XRGs, the bulk of the evidence indicates that most of them are best explained by the jet-shell interaction or spin-flip hypotheses.

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Section: A Jet-shell Interaction Model For Xrgsmentioning

confidence: 93%

On the origin of X-shaped radio galaxies

Gopal-Krishna

Biermann

Gergely

et al. 2012

Res. Astron. Astrophys.

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“…The first is 3C 433 that shows a peculiar radio morphology. The South radio lobe has the presence of a well defined hot-spot, while the northern radio jets bends dramatically toward the West, forming a rather diffuse lobe (Black et al 1992). The second is 3C 93.1, a Compact Steep Spectrum source (Akujor et al 1991) too compact (∼0.…”

Section: Spectroscopic Classes Vs Radio Morphologymentioning

confidence: 99%

An optical spectroscopic survey of the 3CR sample of radio galaxies withz$\mathsf{<}$ 0.3

Buttiglione¹,

Capetti

Celotti³

et al. 2010

A&A

255

390

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In a previous paper we presented a homogeneous and 92% complete optical spectral dataset of the 3CR radio sources with redshift <0.3. Here we use the emission line measurements to explore the spectroscopic properties of the sample. The 3CR sources show a bimodal distribution of excitation index, a new spectroscopic indicator that measures the relative intensity of low and high excitation lines. This unveils the presence of two main sub-populations of radio-loud AGN to which we refer to, following previous studies, as high and low excitation galaxies (HEG and LEG, respectively). In addition to the two main classes, we find one source with a spectrum typical of star forming galaxies, and 3 objects of extremely low level of excitation. All broad-line objects are HEG from the point of view of their narrow emission line ratios and all HEG are FR II radio-galaxies with log L 178 [erg s −1 ] > ∼ 32.8. Conversely LEG cover the whole range of radio power encompassed by this 3CR subsample (30.7 < ∼ log L 178 < ∼ 35.4) and they are of both FR I and FR II type. The brightest LEG are all FR II. HEG and LEG obey to two (quasi) linear correlations between the optical line and extended radio luminosities, with HEG being brighter than LEG in the [O III] line by a factor of ∼10. HEG and LEG are offset also in a plane that compares the black hole mass and the ionizing nuclear luminosity. However, although HEG are associated with higher nuclear luminosities, we find LEG among the brightest radio sources of the sample and with a clear FR II morphology, indistinguishable from those seen in HEG. This suggests that LEG are not simply objects with a lower level of accretion. We speculate that the differences between LEG and HEG are related to a different mode of accretion: LEG are powered by hot gas, while HEG require the presence of cold accreting material. The high temperature of the accreting gas in LEG accounts for the lack of "cold" structures (i.e. molecular torus and broad line region), for the reduced radiative output of the accretion disk, and for the lower gas excitation.

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“…I visually inspected the images of double-lobed radio sources published in Black et al (1992), Lonsdale et al (1993), Price et al (1993), Bogers et al (1994), Bridle et al (1994), Law-Green et al (1995), Neff et al (1995), Reid et al (1995Reid et al ( , 1999, Fernini et al (1997), Hardcastle et al (1997), Harvanek & Hardcastle (1998), Riley et al (1999), Gilbert et al (2004, hereafter G04), Fernini (2007, and Kharb et al (2008) to find objects meeting these criteria. It turned out that only two sources -3C 249.1 and 3C 334 -clearly met them, so they are discussed in detail below.…”

Section: In Quest Of J1211+743 Analoguesmentioning

confidence: 99%

Are 3C 249.1 and 3C 334 restarted quasars?

Marecki

2012

A&A

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This Research Note follows up a Letter in which I posit that J1211+743 is a restarted radio source. This means that its structure, where the jet points to the relic lobe, is only apparently paradoxical. Here, I propose the same scenario and apply the same mathematical model to 3C 249.1 and 3C 334. The ultimate result of my investigation is that these two well-known radio-loud quasars can be understood best so far if it was assumed that they, too, had been restarted.

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A study of FRII radio galaxies with $z \lt 0.15$ – I. High-resolution maps of eight sources at 3.6 cm

Cited by 133 publications

References 0 publications

On the origin of X-shaped radio galaxies

On the origin of X-shaped radio galaxies

An optical spectroscopic survey of the 3CR sample of radio galaxies withz$\mathsf{<}$ 0.3

Are 3C 249.1 and 3C 334 restarted quasars?

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