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Evidence that the AGN dominates the radio emission in z ~ 1 radio-quiet quasars

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Evidence that the AGN dominates the radio emission in z ~ 1 radio-quiet quasars. / White, Sarah V.; Jarvis, Matt J.; Kalfountzou, Eleni; Hardcastle, Martin; Verma, Aprajita; Orjales, José M. Cao; Stevens, Jason.

In: Monthly Notices of the Royal Astronomical Society, 02.02.2017.

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White, Sarah V. ; Jarvis, Matt J. ; Kalfountzou, Eleni ; Hardcastle, Martin ; Verma, Aprajita ; Orjales, José M. Cao ; Stevens, Jason. / Evidence that the AGN dominates the radio emission in z ~ 1 radio-quiet quasars. In: Monthly Notices of the Royal Astronomical Society. 2017.

Bibtex

@article{d236e1a0a53f4fb6ab0fb6a5d783f786,
title = "Evidence that the AGN dominates the radio emission in z ~ 1 radio-quiet quasars",
abstract = "In order to understand the role of radio-quiet quasars (RQQs) in galaxy evolution, we must determine the relative levels of accretion and star-formation activity within these objects. Previous work at low radio flux-densities has shown that accretion makes a significant contribution to the total radio emission, in contrast with other quasar studies that suggest star formation dominates. To investigate, we use 70 RQQs from the Spitzer-Herschel Active Galaxy Survey. These quasars are all at $z$ ~ 1, thereby minimising evolutionary effects, and have been selected to span a factor of ~100 in optical luminosity, so that the luminosity dependence of their properties can be studied. We have imaged the sample using the Karl G. Jansky Very Large Array (JVLA), whose high sensitivity results in 35 RQQs being detected above 2 $\sigma$. This radio dataset is combined with far-infrared luminosities derived from grey-body fitting to Herschel photometry. By exploiting the far-infrared--radio correlation observed for star-forming galaxies, and comparing two independent estimates of the star-formation rate, we show that star formation alone is not sufficient to explain the total radio emission. Considering RQQs above a 2-$\sigma$ detection level in both the radio and the far-infrared, 92 per cent are accretion-dominated, and the accretion process accounts for 80 per cent of the radio luminosity when summed across the objects. The radio emission connected with accretion appears to be correlated with the optical luminosity of the RQQ, whilst a weaker luminosity-dependence is evident for the radio emission connected with star formation.",
keywords = "galaxies: active, galaxies: star formation, galaxies: evolution, galaxies: high redshift, quasars: general, radio continuum: galaxies",
author = "White, {Sarah V.} and Jarvis, {Matt J.} and Eleni Kalfountzou and Martin Hardcastle and Aprajita Verma and Orjales, {Jos{\'e} M. Cao} and Jason Stevens",
note = "This document is the Accepted Manuscript version of the following article: Sarah V. White, Matt J. Jarvis, Eleni Kalfoutnzou, Martin J. Hardcastle, Aprajita Verma, Mose M. Cao Orjales, and Jason Stevens, 'Evidence that the AGN dominates the radio emission in z ~ 1 radio quiet quasars', Monthly Notices of the Royal Astronomical Society, first published online 3 February 2017, DOI: https://doi.org/10.1093/mnras/stx284 Key results are presented in Table 4 and Figure 7, which illustrates where the RQQs lie in relation to the far-infrared--radio correlation {\textcopyright} 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.",
year = "2017",
month = feb,
day = "2",
doi = "10.1093/mnras/stx284",
language = "English",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",

}

RIS

TY - JOUR

T1 - Evidence that the AGN dominates the radio emission in z ~ 1 radio-quiet quasars

AU - White, Sarah V.

AU - Jarvis, Matt J.

AU - Kalfountzou, Eleni

AU - Hardcastle, Martin

AU - Verma, Aprajita

AU - Orjales, José M. Cao

AU - Stevens, Jason

N1 - This document is the Accepted Manuscript version of the following article: Sarah V. White, Matt J. Jarvis, Eleni Kalfoutnzou, Martin J. Hardcastle, Aprajita Verma, Mose M. Cao Orjales, and Jason Stevens, 'Evidence that the AGN dominates the radio emission in z ~ 1 radio quiet quasars', Monthly Notices of the Royal Astronomical Society, first published online 3 February 2017, DOI: https://doi.org/10.1093/mnras/stx284 Key results are presented in Table 4 and Figure 7, which illustrates where the RQQs lie in relation to the far-infrared--radio correlation © 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.

PY - 2017/2/2

Y1 - 2017/2/2

N2 - In order to understand the role of radio-quiet quasars (RQQs) in galaxy evolution, we must determine the relative levels of accretion and star-formation activity within these objects. Previous work at low radio flux-densities has shown that accretion makes a significant contribution to the total radio emission, in contrast with other quasar studies that suggest star formation dominates. To investigate, we use 70 RQQs from the Spitzer-Herschel Active Galaxy Survey. These quasars are all at $z$ ~ 1, thereby minimising evolutionary effects, and have been selected to span a factor of ~100 in optical luminosity, so that the luminosity dependence of their properties can be studied. We have imaged the sample using the Karl G. Jansky Very Large Array (JVLA), whose high sensitivity results in 35 RQQs being detected above 2 $\sigma$. This radio dataset is combined with far-infrared luminosities derived from grey-body fitting to Herschel photometry. By exploiting the far-infrared--radio correlation observed for star-forming galaxies, and comparing two independent estimates of the star-formation rate, we show that star formation alone is not sufficient to explain the total radio emission. Considering RQQs above a 2-$\sigma$ detection level in both the radio and the far-infrared, 92 per cent are accretion-dominated, and the accretion process accounts for 80 per cent of the radio luminosity when summed across the objects. The radio emission connected with accretion appears to be correlated with the optical luminosity of the RQQ, whilst a weaker luminosity-dependence is evident for the radio emission connected with star formation.

AB - In order to understand the role of radio-quiet quasars (RQQs) in galaxy evolution, we must determine the relative levels of accretion and star-formation activity within these objects. Previous work at low radio flux-densities has shown that accretion makes a significant contribution to the total radio emission, in contrast with other quasar studies that suggest star formation dominates. To investigate, we use 70 RQQs from the Spitzer-Herschel Active Galaxy Survey. These quasars are all at $z$ ~ 1, thereby minimising evolutionary effects, and have been selected to span a factor of ~100 in optical luminosity, so that the luminosity dependence of their properties can be studied. We have imaged the sample using the Karl G. Jansky Very Large Array (JVLA), whose high sensitivity results in 35 RQQs being detected above 2 $\sigma$. This radio dataset is combined with far-infrared luminosities derived from grey-body fitting to Herschel photometry. By exploiting the far-infrared--radio correlation observed for star-forming galaxies, and comparing two independent estimates of the star-formation rate, we show that star formation alone is not sufficient to explain the total radio emission. Considering RQQs above a 2-$\sigma$ detection level in both the radio and the far-infrared, 92 per cent are accretion-dominated, and the accretion process accounts for 80 per cent of the radio luminosity when summed across the objects. The radio emission connected with accretion appears to be correlated with the optical luminosity of the RQQ, whilst a weaker luminosity-dependence is evident for the radio emission connected with star formation.

KW - galaxies: active

KW - galaxies: star formation

KW - galaxies: evolution

KW - galaxies: high redshift

KW - quasars: general

KW - radio continuum: galaxies

U2 - 10.1093/mnras/stx284

DO - 10.1093/mnras/stx284

M3 - Article

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

ER -