Radio-loud Narrow-Line Type 1 Quasars

Komossa, Stefanie; Voges, W.; Xu, Dawei; Mathur, S.; Adorf, H. M.; Lemson, Gerard; Duschl, W. J.; Grupe, D.

doi:10.1086/505043

Cited by 344 publications

(517 citation statements)

References 142 publications

(220 reference statements)

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“…2). Most of the mildly radio-loud NLS1 galaxies of Komossa et al (2006a) are steep-spectrum sources, and do not show indications of beaming, while three sources are more similar to blazars. In terms of their optical emission-line properties and BH masses, the RLNLS1s are similar to the radio-quiet NLS1 (RQNLS1) population as a whole.…”

Section: Introductionmentioning

confidence: 93%

“…Remillard et al 1986, Oshlack et al 2001, Zhou et al 2003 seemed to be exceptions, rather than the tip of an iceberg. The early surveys revealed only a handful of objects: 11 by Zhou & Wang (2002) and Komossa et al (2006a), and 16 by Whalen et al (2006). Williams et al (2002) analysed 150 NLS1s from the Sloan Digital Sky Survey (SDSS) Early Data Release, and only a dozen (8%) were detected at radio frequencies and only two (1.3%) are radio loud, i.e.…”

Section: Introductionmentioning

confidence: 99%

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Properties of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

Foschini

Berton

Caccianiga

et al. 2015

A&A

188

344

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We have conducted a multiwavelength survey of 42 radio loud narrow-1ine Seyfert 1 galaxies (RLNLS1s), selected by searching among all the known sources of this type and omitting those with steep radio spectra. We analyse data from radio frequencies to X-rays, and supplement these with information available from online catalogues and the literature in order to cover the full electromagnetic spectrum. This is the largest known multiwavelength survey for this type of source. We detected 90% of the sources in X-rays and found 17% at γ rays. Extreme variability at high energies was also found, down to timescales as short as hours. In some sources, dramatic spectral and flux changes suggest interplay between a relativistic jet and the accretion disk. The estimated masses of the central black holes are in the range ∼ 10 6−8 M ⊙ , lower than those of blazars, while the accretion luminosities span a range from ∼ 0.01 to ∼ 0.49 times the Eddington limit, with an outlier at 0.003, similar to those of quasars. The distribution of the calculated jet power spans a range from ∼ 10 42.6 to ∼ 10 45.6 erg s −1 , generally lower than quasars and BL Lac objects, but partially overlapping with the latter. Once normalised by the mass of the central black holes, the jet power of the three types of active galactic nuclei are consistent with each other, indicating that the jets are similar and the observational differences are due to scaling factors. Despite the observational differences, the central engine of RLNLS1s is apparently quite similar to that of blazars. The historical difficulties in finding radio-loud narrow-line Seyfert 1 galaxies might be due to their low power and to intermittent jet activity.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Properties of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

Foschini

Berton

Caccianiga

et al. 2015

A&A

188

344

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“…Both paradigms are also discussed for γ-NLS1(e.g., Abdo et al 2009c;Foschini et al 2015;Berton et al 2015), and it has been proposed that CSS and RL-NLS1 are linked (e.g., Komossa et al 2006;Doi et al 2012;Caccianiga et al 2014;Komossa et al 2015;Gu et al 2015). Recently, Caccianiga et al (2015) have found evidence of significant star formation activity in a sample of RL-NLS1s, favouring the scenario that RL-NLS1s are young AGNs.…”

Section: Parsec-scale Structure and Jet Orientationmentioning

confidence: 99%

“…However, the total number of known RL-NLS1s has increased in recent years. The first dedicated study and search of RL-NLS1s was performed by Komossa et al (2006), yielding a sample of 11 sources most of which were previously not known to be RL-NLS1s. Then, Yuan et al (2008) compiled a genuine sample of 23 RL-NLS1s with RL 1.4 GHz > 100, with black hole masses of 10 6 -10 8 M and Eddingtion ratios R Edd ≈ 1.…”

Section: Introductionmentioning

confidence: 99%

The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004−447

Schulz

Kreikenbohm

Kadler

et al. 2016

A&A

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Context. Γ-ray-detected radio-loud narrow-line Seyfert 1 (γ-NLS1) galaxies constitute a small but interesting sample of the γ-ray-loud AGN. The radio-loudest γ-NLS1 known, PKS 2004−447, is located in the southern hemisphere and is monitored in the radio regime by the multiwavelength monitoring programme TANAMI. Aims. We aim for the first detailed study of the radio morphology and long-term radio spectral evolution of PKS 2004−447, which are essential for understanding the diversity of the radio properties of γ-NLS1s. Methods. The TANAMI VLBI monitoring program uses the Australian Long Baseline Array (LBA) and telescopes in Antarctica, Chile, New Zealand, and South Africa to monitor the jets of radio-loud active galaxies in the southern hemisphere. Lower resolution radio flux density measurements at multiple radio frequencies over four years of observations were obtained with the Australia Telescope Compact Array (ATCA). Results. The TANAMI VLBI image at 8.4 GHz shows an extended one-sided jet with a dominant compact VLBI core. Its brightness temperature is consistent with equipartition, but it is an order of magnitude below other γ-NLS1s with the sample value varying over two orders of magnitude. We find a compact morphology with a projected large-scale size <11 kpc and a persistent steep radio spectrum with moderate flux-density variability. Conclusions. PKS 2004−447 appears to be a unique member of the γ-NLS1 sample. It exhibits blazar-like features, such as a flat featureless X-ray spectrum and a core-dominated, one-sided parsec-scale jet with indications for relativistic beaming. However, the data also reveal properties atypical for blazars, such as a radio spectrum and large-scale size consistent with compact-steep-spectrum (CSS) objects, which are usually associated with young radio sources. These characteristics are unique among all γ-NLS1s and extremely rare among γ-ray-loud AGN.

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“…Hence, these objects are often branded "winged" or "X-shaped" radio galaxies (Leahy & Williams 1984;Leahy & Parma 1992). A recent merger of two supermassive black holes (SMBHs), where the wings constitute the relic emission of the past radio jets, is one of several scenarios proposed to explain this peculiar radio morphology (e.g., Rottmann 2001;Merritt & Ekers 2002;Komossa 2006;Gergely & Biermann 2009;Hodges-Kluck et al 2010b;Mezcua et al 2011). Alternative models employ jet-axis reorientation (e.g., Dennett-Thorpe et al 2002), two unresolved active galactic nuclei (AGN; Lal & Rao 2007), backflow of material from the main lobes into the wings (e.g., Leahy & Williams 1984;Capetti et al 2002;Hodges-Kluck et al 2010a;Landt et al 2010;Hodges-Kluck & Reynolds 2011), or non-ballistic precession assuming a pre-merger state of the two black holes (BHs; Gong 2008;Gong et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Starbursts and black hole masses in X-shaped radio galaxies: Signatures of a merger event?

Mezcua

Chavushyan

Lobanov

2012

A&A

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We present new spectroscopic identifications of 12 X-shaped radio galaxies and use the spectral data to derive starburst histories and masses of the nuclear supermassive black holes in these galaxies. The observations were done with the 2.1-m telescope of the Observatorio Astronómico Nacional at San Pedro Mártir, México. The new spectroscopic results extend the sample of X-shaped radio galaxies studied with optical spectroscopy. We show that the combined sample of the X-shaped radio galaxies has statistically higher black-hole masses and older episodes of star formation than a control sample of canonical double-lobed radio sources with similar redshifts and luminosities. The data reveal enhanced star-formation activity in the X-shaped sample on the timescales expected in galactic mergers. We discuss the results obtained in the framework of the merger scenario.

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Radio-loud Narrow-Line Type 1 Quasars

Cited by 344 publications

References 142 publications

Properties of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

Properties of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004−447

Starbursts and black hole masses in X-shaped radio galaxies: Signatures of a merger event?

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