Radio lobes and forbidden O III profile substructure in Seyfert galaxies

Whittle, M.; Pedlar, A.; Meurs, E. J. A.; Unger, S. W.; Axon, D. J.; Ward, M. J.

doi:10.1086/166074

Cited by 115 publications

(137 citation statements)

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“…Our results are comparable with similar studies of Seyfert galaxies (e.g. Whittle et al 1988) and support the unification scheme in which radio-quiet quasars are assumed to be the luminous cousins of Seyferts. However, the excitation as measured from the [O iii]/Hβ ratio turns out to be generally lower for our quasars (∼5-8) than for Seyfert galaxies (∼10-12, Whittle et al 1988).…”

Section: Discussionsupporting

confidence: 91%

“…The radio structure is known in many cases to comprise linear double or triple sources (Ulvestad & Wilson 1984a,b;Schmitt et al 2001) and the emission-line morphologies often show a rich variety such as strands or bow-shock like structures (Falcke et al 1998;Whittle et al 2004). Whittle et al (1988) observed ten Seyfert galaxies with aligned multiple radio structures and found clear evidence for While quasars are assumed to be the luminous cousins of Seyfert galaxies, there is a significant lack of comparable Based on observations made with ESO Telescopes at the La Silla Observatory under programme ID 73.B-0290. dedicated quasar NLR studies.…”

Section: Introductionmentioning

confidence: 99%

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[$\ion{O}{iii}$] profile substructure in radio–quiet quasars

Leipski

Bennert

2006

A&A

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Interactions between the radio jet and the optical emission of the narrow-line region (NLR) are a well known phenomenon in Seyfert galaxies. Here, we present the study of possible jet-NLR interactions in five radio-quiet PG quasars with double or triple radio structure. High spatial and spectral resolution observations were carried out in the Hβ-[O iii] λ5007 wavelength range. In all cases, there is evidence for [O iii] profile substructure (shoulders, subpeaks, blueshifted "broad" components) with different clarity. To measure the velocity, line width, intensity, and location of these [O iii] components, several Gaussians were fitted. Often, the substructures are more pronounced close to the radio lobes, suggestive of jet-NLR interactions. Our observations support the unification scheme in which radio-quiet quasars are assumed to be the luminous cousins of Seyfert galaxies.

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

[$\ion{O}{iii}$] profile substructure in radio–quiet quasars

Leipski

Bennert

2006

A&A

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“…Jet-cloud interactions have also been implicated in the severe bending of radio outflows from parsec scales to 100 pc scales in other radio-quiet AGNs (e.g., Irwin & Seaquist 1988;Veilleux et al 1993;Steffen et al 1996;Daigle & Roy 2001;Middelberg et al 2004). Morphological correspondences between optical emission-line filaments within the NLR and radio jet substructure further argues in favor of jet-ISM interaction (e.g., Whittle et al 1986Whittle et al , 1988Unger et al 1988;Pedlar et al 1989;Taylor et al 1989Taylor et al , 1992Bower et al 1994Bower et al , 1995Capetti et al 1995aCapetti et al , 1995bCapetti et al , 1996Capetti et al , 1997Capetti et al , 1999Ferruit et al 1998;Whittle & Wilson 2004).…”

Section: Jet Misalignmentsmentioning

confidence: 99%

A Survey of Kiloparsec-Scale Radio Outflows in Radio-Quiet Active Galactic Nuclei

et al. 2006

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Seyfert galaxies commonly host compact jets spanning 10-100 pc scales, but larger structures are resolved out in long-baseline aperture synthesis surveys. Previous, targeted studies showed that kiloparsec-scale radio structures ( KSRs) may be a common feature of Seyfert and LINER galaxies, and the origin of KSRs may be starbursts or active galactic nuclei (AGNs). We report a new Very Large Array survey of a complete sample of Seyfert and LINER galaxies. Out of all of the surveyed radio-quiet sources, we find that 44% (19 out of 43) show extended radio structures at least 1 kpc in total extent that do not match the morphology of the disk or its associated star-forming regions. The detection rate is a lower limit owing to the combined effects of projection and resolution. The infrared colors of the KSR host galaxies are unremarkable compared to other Seyfert galaxies, and the large-scale outflows orient randomly with respect to the host galaxy axes. The KSR Seyfert galaxies instead stand out by deviating significantly from the far-infrared-radio correlation for star-forming galaxies, with tendency toward radio excess, and they are more likely to have a relatively luminous, compact radio source in the nucleus; these results argue that KSRs are powered by the AGNs rather than starbursts. The high detection rate indicates that Seyfert galaxies generate radio outflows over a significant fraction of their lifetime, which is much longer than the dynamical timescale of an AGNpowered jet but is comparable instead to the buoyancy timescale. The likely explanation is that the KSRs originate from jet plasma that has been decelerated by interaction with the nuclear interstellar medium ( ISM ). Based on a simple ram pressure argument, the kinetic power of the jet on kiloparsec scales is about 3 orders of magnitude weaker than the power of the jet on 10-100 pc scales. This result is consistent with the interaction model, in which case virtually all of the jet power must be lost to the ISM within the inner kiloparsec.

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“…In particular, a few galaxies with double-peaked [O iii], and perhaps Hβ, emission lines have been presented as candidate binary AGNs, each AGN with its own narrow-line region (NLR; Zhou et al 2004;Gerke et al 2007;Comerford et al 2009a). Doublepeaked [O iii] emission has also occasionally been observed in some nearby AGNs since the 1980s (e.g., Heckman et al 1981;Whittle et al 1988;Veilleux 1991aVeilleux , 1991b, among them some that have all lines double-peaked. At that time, processes linked to radio(jet) activity had been suggested to explain these line profiles.…”

Section: Introductionmentioning

confidence: 95%

Narrow Double-Peaked Emission Lines of SDSS J131642.90+175332.5: Signature of a Single or a Binary Agn in a Merger, Jet-Cloud Interaction, or Unusual Narrow-Line Region Geometry

Komossa

2009

ApJ

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We present an analysis of the active galaxy SDSS J131642.90+175332.5, which is remarkable because all of its narrow emission lines are double-peaked, and because it additionally shows an extra broad component (FHWM ∼ 1400 km s −1 ) in most of its forbidden lines, peaking in between the two narrow systems. The peaks of the two narrow systems are separated by 400-500 km s −1 in velocity space. The spectral characteristics of double-peaked [O iii] emission have previously been interpreted as a signature of dual or binary active galactic nuclei (AGNs), among other models. In the context of the binary scenario, SDSS J131642.90+175332.5 is a particularly good candidate because not just one line but all of its emission lines are double-peaked. However, we also discuss a number of other scenarios which can potentially account for double-peaked narrow emission lines, including projection effects, a two-sided outflow, jet-cloud interactions, special narrow-line region (NLR) geometries (disks, bars, or inner spirals), and a galaxy merger with only one AGN illuminating two NLRs. We argue that the similarity of the emission-line ratios in both systems, and the presence of the very unusual broad component at intermediate velocity, makes a close pair of unrelated AGNs unlikely, and rather argues for processes in a single galaxy or merger. We describe future observations that can distinguish between these remaining possibilities.

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Radio lobes and forbidden O III profile substructure in Seyfert galaxies

Cited by 115 publications

References 0 publications

[$\ion{O}{iii}$] profile substructure in radio–quiet quasars

[$\ion{O}{iii}$] profile substructure in radio–quiet quasars

A Survey of Kiloparsec-Scale Radio Outflows in Radio-Quiet Active Galactic Nuclei

Narrow Double-Peaked Emission Lines of SDSS J131642.90+175332.5: Signature of a Single or a Binary Agn in a Merger, Jet-Cloud Interaction, or Unusual Narrow-Line Region Geometry

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