Jetted Narrow-Line Seyfert 1 Galaxies &amp; Co.: Where Do We Stand?

Foschini, L.

doi:10.3390/universe6090136

Cited by 31 publications

(33 citation statements)

References 271 publications

(301 reference statements)

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“…It is noteworthy that all these sources host powerful jets, but reside in late-type galaxies, directly contradicting the traditional jet paradigm (Laor, 2000). So much evidence has gathered against it after it was formulated that we should finally let go of it, and see the host galaxy as well as the black hole mass as one factor affecting the evolution and properties of AGN, but definitely not the determining one (Foschini, 2020).…”

Section: Host Galaxiesmentioning

confidence: 99%

“…So far ∼20 NLS1s have been detected in gamma-rays, showing that, just like blazars and radio galaxies, NLS1s can harbour powerful relativistic jets (Romano et al, 2018;Järvelä et al, 2020;Rakshit et al, 2021). These NLS1s might be the progenitors of more powerful jetted AGN, like flat-spectrum radio quasars (Foschini et al, 2015;Foschini, 2017;Foschini, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Narrow-Line Seyfert 1 Galaxies With Absorbed Jets–Insights From Radio Spectral Index Maps

Järvelä

Berton

Crepaldi

2021

Front. Astron. Space Sci.

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Narrow-line Seyfert 1 (NLS1) galaxies are active galactic nuclei (AGN) believed to be in the early stages of their evolution. A fraction of them have been found to host relativistic jets. Due to the lack of large-scale diffuse radio emission they are believed to be experiencing one of their first activity cycles, and can offer us an opportunity to study the early evolution of more powerful AGN, such as radio galaxies and flat-spectrum radio quasars. Recently, a group of intriguing jetted NLS1s was discovered: based on high radio frequency data they host relativistic jets, but in the JVLA observations they all showed steep radio spectra at least up to 9.0 GHz, indicating very strong absorption at these frequencies. In this paper we study a subset of these sources in detail by employing spatially resolved radio spectral index maps at central frequencies of 1.6, 5.2, and 9.0 GHz. With spectral index maps we can disentangle the different radio emission components over the radio-emitting region, and get insights into the production mechanisms of radio emission. In addition, we study their host galaxies in relation to the radio emission to investigate if the host can provide us additional information regarding the origin of the radio emission, or the launching mechanism of the jets. It is fascinating how different the sources studied are, and certainly more, especially wide frequency-range, and high-resolution observations will be needed to understand their history and current properties, such as the reason behind the extraordinary radio spectra.

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Section: Host Galaxiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Narrow-Line Seyfert 1 Galaxies With Absorbed Jets–Insights From Radio Spectral Index Maps

Järvelä

Berton

Crepaldi

2021

Front. Astron. Space Sci.

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“…This finding is also in agreement with the main result of B16. In that work, however, the adopted radio classification was based on the radio-loudness criterion, which has been repeatedly proven to be rather ineffective [33,57,58,69,70,72,73]. In this work, instead, we make use of a more rigorous classification based directly on the observed radio properties and morphology of the sources.…”

Section: Origin Of the Bulk Outflowsmentioning

confidence: 99%

“…NLS1s are mostly non-jetted sources, but some of them do actually harbor powerful relativistic jets [9][10][11][12][13]. Typically hosted by spiral galaxies [14][15][16][17][18][19][20][21][22][23][24][25], due to their low-mass BHs and high Eddington ratios NLS1s are believed to be the progenitors of other AGN classes, such as broad-line Seyfert 1 galaxies and flat-spectrum radio quasars [8,[26][27][28][29][30][31][32][33]. Since their classification is exclusively based on the width of the Hβ line [34], NLS1s can currently be found only up to z∼1 [35], although unclassified objects with similar properties are present also at higher redshift [36,37].…”

Section: Introductionmentioning

confidence: 99%

Jet-Induced Feedback in the [O III] Lines of Early Evolution Stage Active Galactic Nuclei

Berton

Järvelä

2021

Universe

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It is well known that active galactic nuclei (AGN) show various forms of interaction with their host galaxy, in a number of phenomena generally called AGN feedback. In particular, the relativistic plasma jets launched by a fraction of AGN can strongly affect their environment. We present here a study of the [O III] λλ4959,5007 lines in a diverse sample of early evolution stage AGN–specifically narrow-line Seyfert 1 galaxies. Radio imaging observations of all of the sources enable a division to jetted and non-jetted sources, and exploiting this we show that the ionized gas properties are significantly influenced by the presence of the jets, as we often find the [O III] lines (blue-)shifted with respect to their restframe wavelength. We also show how the radio morphology and the radio spectral index do not seem to play a role in the origin of the [O III] shifts, thus suggesting that the source inclination is not relevant to the lines displacement. We do not find a strong relation between the [O III] line properties and the bolometric luminosity, suggesting that within our sample radiatively driven outflows do not seem to have a significant contribution to the [O III] line kinematics. We finally suggest that [O III] shifts may be a good proxy to identify the presence of relativistic jets. Additional studies, especially with integral-field spectroscopy, will provide a deeper insight into the relation between jets and their environment in early evolution stage AGN.

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“…They obtain different growth rates depending on the dynamoc coefficient. L. Foschini [14] critically reviews the literature of recent years on several sources of high-energy gamma-rays such as Narrow-Line Seyfert 1 Galaxies (NLS1s) and other Active Galactic Nuclei (AGN). In particular, he focuses on the paradigm of a central engine powered by a relatively small-mass black hole common to such a variety of objects.…”

mentioning

confidence: 99%