Absorbed relativistic jets in radio-quiet narrow-line Seyfert 1 galaxies

Marco Berton; Emilia Järvelä; L. Crepaldi; Anne Lähteenmäki; Merja Tornikoski; E. Congiu; P. Kharb; G. Terreran; A. Vietri

doi:10.1051/0004-6361/202037793

Absorbed relativistic jets in radio-quiet narrow-line Seyfert 1 galaxies

Marco Berton^*
, Emilia Järvelä
, L. Crepaldi
, Anne Lähteenmäki
, Merja Tornikoski
, E. Congiu
, P. Kharb
, G. Terreran
, A. Vietri

^*Corresponding author for this work

Research output: Contribution to journal › Article › Scientific › peer-review

34 Citations (Scopus)

159 Downloads (Pure)

Abstract

Narrow-line Seyfert 1 (NLS1) galaxies are peculiar active galactic nuclei. Most of them do not show strong radio emission, but seven radio-quiet (or radio-silent) NLS1s have recently been detected flaring multiple times at 37 GHz by the Metsahovi Radio Telescope, indicating relativistic jets in these peculiar sources. We observed them with the Karl G. Jansky Very Large Array (JVLA) in A configuration at 1.6, 5.2, and 9.0 GHz. Our results show that these sources are either extremely faint or not detected in the JVLA bands. At these frequencies, the radio emission from their relativistic jet must be absorbed, either through synchrotron self-absorption as it occurs in gigahertz-peaked sources, or more likely, through free-free absorption by a screen of ionized gas associated with starburst activity or shocks. Our findings cast new shadows on the radio-loudness criterion, which seems to be increasingly frequently a misleading parameter. New high-frequency and high-resolution radio observations are essential to test our hypotheses.

Original language	English
Article number	A64
Number of pages	9
Journal	Astronomy & Astrophysics
Volume	636
DOIs	https://doi.org/10.1051/0004-6361/202037793
Publication status	Published - 17 Apr 2020
MoE publication type	A1 Journal article-refereed

Funding

Acknowledgements. G.T. acknowledges partial support by the National Science Foundation under Award No. AST-1909796. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This publication makes use of facilities and data obtained at the Metsähovi Radio Observatory, operated by Aalto University, Finland. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Admistration.

Keywords

Galaxies: active
Galaxies: jets
Galaxies: Seyfert
Radio continuum: galaxies

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10.1051/0004-6361/202037793

Berton_Absorbed_relativistic_jets_AandAFinal published version, 488 KB

Cite this

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title = "Absorbed relativistic jets in radio-quiet narrow-line Seyfert 1 galaxies",

abstract = "Narrow-line Seyfert 1 (NLS1) galaxies are peculiar active galactic nuclei. Most of them do not show strong radio emission, but seven radio-quiet (or radio-silent) NLS1s have recently been detected flaring multiple times at 37 GHz by the Metsahovi Radio Telescope, indicating relativistic jets in these peculiar sources. We observed them with the Karl G. Jansky Very Large Array (JVLA) in A configuration at 1.6, 5.2, and 9.0 GHz. Our results show that these sources are either extremely faint or not detected in the JVLA bands. At these frequencies, the radio emission from their relativistic jet must be absorbed, either through synchrotron self-absorption as it occurs in gigahertz-peaked sources, or more likely, through free-free absorption by a screen of ionized gas associated with starburst activity or shocks. Our findings cast new shadows on the radio-loudness criterion, which seems to be increasingly frequently a misleading parameter. New high-frequency and high-resolution radio observations are essential to test our hypotheses.",

keywords = "Galaxies: active, Galaxies: jets, Galaxies: Seyfert, Radio continuum: galaxies",

author = "Marco Berton and Emilia J{\"a}rvel{\"a} and L. Crepaldi and Anne L{\"a}hteenm{\"a}ki and Merja Tornikoski and E. Congiu and P. Kharb and G. Terreran and A. Vietri",

year = "2020",

month = apr,

day = "17",

doi = "10.1051/0004-6361/202037793",

language = "English",

volume = "636",

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T1 - Absorbed relativistic jets in radio-quiet narrow-line Seyfert 1 galaxies

AU - Berton, Marco

AU - Järvelä, Emilia

AU - Crepaldi, L.

AU - Lähteenmäki, Anne

AU - Tornikoski, Merja

AU - Congiu, E.

AU - Kharb, P.

AU - Terreran, G.

AU - Vietri, A.

PY - 2020/4/17

Y1 - 2020/4/17

N2 - Narrow-line Seyfert 1 (NLS1) galaxies are peculiar active galactic nuclei. Most of them do not show strong radio emission, but seven radio-quiet (or radio-silent) NLS1s have recently been detected flaring multiple times at 37 GHz by the Metsahovi Radio Telescope, indicating relativistic jets in these peculiar sources. We observed them with the Karl G. Jansky Very Large Array (JVLA) in A configuration at 1.6, 5.2, and 9.0 GHz. Our results show that these sources are either extremely faint or not detected in the JVLA bands. At these frequencies, the radio emission from their relativistic jet must be absorbed, either through synchrotron self-absorption as it occurs in gigahertz-peaked sources, or more likely, through free-free absorption by a screen of ionized gas associated with starburst activity or shocks. Our findings cast new shadows on the radio-loudness criterion, which seems to be increasingly frequently a misleading parameter. New high-frequency and high-resolution radio observations are essential to test our hypotheses.

AB - Narrow-line Seyfert 1 (NLS1) galaxies are peculiar active galactic nuclei. Most of them do not show strong radio emission, but seven radio-quiet (or radio-silent) NLS1s have recently been detected flaring multiple times at 37 GHz by the Metsahovi Radio Telescope, indicating relativistic jets in these peculiar sources. We observed them with the Karl G. Jansky Very Large Array (JVLA) in A configuration at 1.6, 5.2, and 9.0 GHz. Our results show that these sources are either extremely faint or not detected in the JVLA bands. At these frequencies, the radio emission from their relativistic jet must be absorbed, either through synchrotron self-absorption as it occurs in gigahertz-peaked sources, or more likely, through free-free absorption by a screen of ionized gas associated with starburst activity or shocks. Our findings cast new shadows on the radio-loudness criterion, which seems to be increasingly frequently a misleading parameter. New high-frequency and high-resolution radio observations are essential to test our hypotheses.

KW - Galaxies: active

KW - Galaxies: jets

KW - Galaxies: Seyfert

KW - Radio continuum: galaxies

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DO - 10.1051/0004-6361/202037793

M3 - Article

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VL - 636

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

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ER -

Absorbed relativistic jets in radio-quiet narrow-line Seyfert 1 galaxies

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Metsähovi Radio Observatory

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Absorbed relativistic jets in radio-quiet narrow-line Seyfert 1 galaxies

Abstract

Funding

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Metsähovi Radio Observatory

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