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15-GHz radio emission from nearby low-luminosity active galactic nuclei

15-GHz radio emission from nearby low-luminosity active galactic nuclei
15-GHz radio emission from nearby low-luminosity active galactic nuclei

We present a sub-arcsec resolution radio imaging survey of a sample of 76 low-luminosity active galactic nuclei (LLAGN) that were previously not detected with the Very Large Array at 15 GHz. Compact, parsec-scale radio emission has been detected above a flux density of 40 μ Jy in 60% (45 of 76) of the LLAGN sample. We detect 20 out of 31 (64%) low-ionization nuclear emission-line region (LINER) nuclei, ten out of 14 (71%) low-luminosity Seyfert galaxies, and 15 out of 31 (48%) transition objects. We use this sample to explore correlations between different emission lines and the radio luminosity. We also populate the X-ray and the optical fundamental plane of black hole activity and further refine its parameters. We obtain a fundamental plane relation of log LR = 0.48 (±0.04) log LX + 0.79 (±0.03) log M and an optical fundamental plane relation of log LR = 0.63 (±0.05) log L[O III] + 0.67 (±0.03) log M after including all the LLAGN detected at high resolution at 15 GHz, and the best-studied hard-state X-ray binaries (luminosities are given in erg s-1 while the masses are in units of solar mass). Finally, we find conclusive evidence that the nuclear 15 GHz radio luminosity function (RLF) of all the detected Palomar Sample LLAGN has a turnover at the low-luminosity end, and is best-fitted with a broken power law. The break in the power law occurs at a critical mass accretion rate of 1.2 × 10-3 M yr-1, which translates to an Eddington ratio of mEdd ∼ 5.1 × 10-5, assuming a black hole mass of 109 M. The local group stands closer to the extrapolation of the higher-luminosity sources, and the classical Seyferts agree with the nuclear RLF of the LLAGN in the local universe.

Galaxies: active, Galaxies: jets, Galaxies: luminosity function, mass function, Galaxies: nuclei, Radio continuum: galaxies
0004-6361
Saikia, Payaswini
7d02c74a-4aa7-43ee-b6b0-52ae4a0eaabc
Körding, Elmar
2fb1638c-4392-4acc-83ea-78e0eb9c078b
Coppejans, Deanne L.
9087eb84-f565-482c-b278-25715b96809c
Falcke, Heino
97cd28d8-bd6d-4f15-8a0f-fe98a287b3ef
Williams, David
c9ded967-198f-4c26-96b1-8c03d7d26445
Baldi, Ranieri D.
c416ed4c-5d1c-48ee-989c-3a8ab38cd124
Mchardy, Ian
4f215137-9cc4-4a08-982e-772a0b24c17e
Beswick, Rob
f22e46dc-1928-4ef2-b750-f8e262a6b398
Saikia, Payaswini
7d02c74a-4aa7-43ee-b6b0-52ae4a0eaabc
Körding, Elmar
2fb1638c-4392-4acc-83ea-78e0eb9c078b
Coppejans, Deanne L.
9087eb84-f565-482c-b278-25715b96809c
Falcke, Heino
97cd28d8-bd6d-4f15-8a0f-fe98a287b3ef
Williams, David
c9ded967-198f-4c26-96b1-8c03d7d26445
Baldi, Ranieri D.
c416ed4c-5d1c-48ee-989c-3a8ab38cd124
Mchardy, Ian
4f215137-9cc4-4a08-982e-772a0b24c17e
Beswick, Rob
f22e46dc-1928-4ef2-b750-f8e262a6b398

Saikia, Payaswini, Körding, Elmar, Coppejans, Deanne L., Falcke, Heino, Williams, David, Baldi, Ranieri D., Mchardy, Ian and Beswick, Rob (2018) 15-GHz radio emission from nearby low-luminosity active galactic nuclei. Astronomy & Astrophysics, 616, [A152]. (doi:10.1051/0004-6361/201833233).

Record type: Article

Abstract

We present a sub-arcsec resolution radio imaging survey of a sample of 76 low-luminosity active galactic nuclei (LLAGN) that were previously not detected with the Very Large Array at 15 GHz. Compact, parsec-scale radio emission has been detected above a flux density of 40 μ Jy in 60% (45 of 76) of the LLAGN sample. We detect 20 out of 31 (64%) low-ionization nuclear emission-line region (LINER) nuclei, ten out of 14 (71%) low-luminosity Seyfert galaxies, and 15 out of 31 (48%) transition objects. We use this sample to explore correlations between different emission lines and the radio luminosity. We also populate the X-ray and the optical fundamental plane of black hole activity and further refine its parameters. We obtain a fundamental plane relation of log LR = 0.48 (±0.04) log LX + 0.79 (±0.03) log M and an optical fundamental plane relation of log LR = 0.63 (±0.05) log L[O III] + 0.67 (±0.03) log M after including all the LLAGN detected at high resolution at 15 GHz, and the best-studied hard-state X-ray binaries (luminosities are given in erg s-1 while the masses are in units of solar mass). Finally, we find conclusive evidence that the nuclear 15 GHz radio luminosity function (RLF) of all the detected Palomar Sample LLAGN has a turnover at the low-luminosity end, and is best-fitted with a broken power law. The break in the power law occurs at a critical mass accretion rate of 1.2 × 10-3 M yr-1, which translates to an Eddington ratio of mEdd ∼ 5.1 × 10-5, assuming a black hole mass of 109 M. The local group stands closer to the extrapolation of the higher-luminosity sources, and the classical Seyferts agree with the nuclear RLF of the LLAGN in the local universe.

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More information

Accepted/In Press date: 9 May 2018
e-pub ahead of print date: 7 September 2018
Keywords: Galaxies: active, Galaxies: jets, Galaxies: luminosity function, mass function, Galaxies: nuclei, Radio continuum: galaxies

Identifiers

Local EPrints ID: 426908
URI: http://eprints.soton.ac.uk/id/eprint/426908
ISSN: 0004-6361
PURE UUID: d2a6cb50-7a50-4e96-8865-52fdf41216ce
ORCID for David Williams: ORCID iD orcid.org/0000-0001-7361-0246

Catalogue record

Date deposited: 14 Dec 2018 17:30
Last modified: 28 Aug 2019 16:44

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