The preferentially magnified active nucleus in IRAS F10214+4724 – III. VLBI observations of the radio core

Deane, Roger; Rawlings, Steve; Garrett, M. A.; Heywood, Ian; Jarvis, Matt J.; Klöckner, H.-R.; Marshall, Phil; McKean, J. P.

doi:10.1093/mnras/stt1241

Cited by 15 publications

(13 citation statements)

References 103 publications

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“…It is generally accepted that the enormous luminosity of this galaxy at redshift z = 2.224 is due to gravitational lensing by a foreground galaxy with magnification between 50 and 100 (Broadhurst & Lehar 1995;Serjeant et al 1995) or 15−20 (Deane et al 2013). Following the detection of a silicate emission feature (Teplitz et al 2006) in this narrow-lined object, Efstathiou (2006) and Efstathiou et al (2013) proposed that the emission feature is due to emission from narrow-line region clouds at a temperature of 210 K.…”

Section: Fit To the Hyperluminous Ir Galaxy Iras F10214+4724mentioning

confidence: 99%

Self-consistent two-phase AGN torus models

Siebenmorgen

Heymann

Efstathiou

2015

A&A

131

189

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We assume that dust near active galactic nuclei (AGNs) is distributed in a torus-like geometry, which can be described as a clumpy medium or a homogeneous disk, or as a combination of the two (i.e. a two-phase medium). The dust particles considered are fluffy and have higher submillimeter emissivities than grains in the diffuse interstellar medium. The dust-photon interaction is treated in a fully self-consistent three-dimensional radiative transfer code. We provide an AGN library of spectral energy distributions (SEDs). Its purpose is to quickly obtain estimates of the basic parameters of the AGNs, such as the intrinsic luminosity of the central source, the viewing angle, the inner radius, the volume filling factor and optical depth of the clouds, and the optical depth of the disk midplane, and to predict the flux at yet unobserved wavelengths. The procedure is simple and consists of finding an element in the library that matches the observations. We discuss the general properties of the models and in particular the 10 µm silicate band. The AGN library accounts well for the observed scatter of the feature strengths and wavelengths of the peak emission. AGN extinction curves are discussed and we find that there is no direct one-to-one link between the observed extinction and the wavelength dependence of the dust cross sections. We show that objects in the library cover the observed range of mid-infrared colors of known AGNs. The validity of the approach is demonstrated by matching the SEDs of a number of representative objects: Four Seyferts and two quasars for which we present new Herschel photometry, two radio galaxies, and one hyperluminous infrared galaxy. Strikingly, for the five luminous objects we find that pure AGN models fit the SED without needing to postulate starburst activity.

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Section: Fit To the Hyperluminous Ir Galaxy Iras F10214+4724mentioning

confidence: 99%

Self-consistent two-phase AGN torus models

Siebenmorgen

Heymann

Efstathiou

2015

A&A

131

189

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“…We define only two sources in our sample with established star-formation-dominated radio emission, RX J1131−1231 and IRAS F10214+5255. VLBI experiments to detect the radio core of these quasars suggest the radio emission is primarily due to star formation (Wucknitz & Volino 2008;Deane et al 2013). In all other cases, the emission mechanism is undetermined, either because they are not detected at radio wavelengths or the detections are at too low an angular resolution to discriminate between compact (AGN) or extended (star formation) emission.…”

Section: Radio Propertiesmentioning

confidence: 99%

Gravitational lensing reveals extreme dust-obscured star formation in quasar host galaxies

Stacey

McKean

Robertson

et al. 2018

Monthly Notices of the Royal Astronomical Society

102

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We have observed 104 gravitationally-lensed quasars at z ∼ 1-4 with Herschel/SPIRE, the largest such sample ever studied. By targeting gravitational lenses, we probe intrinsic farinfrared (FIR) luminosities and star formation rates (SFRs) more typical of the population than the extremely luminous sources that are otherwise accessible. We detect 72 objects with Herschel/SPIRE and find 66 percent (69 sources) of the sample have spectral energy distributions (SEDs) characteristic of dust emission. For 53 objects with sufficiently constrained SEDs, we find a median effective dust temperature of 38 +12 −5 K. By applying the radio-infrared correlation, we find no evidence for an FIR excess which is consistent with star-formationheated dust. We derive a median magnification-corrected FIR luminosity of 3.6 +4.8 −2.4 × 10 11 L and median SFR of 120 +160 −80 M yr −1 for 94 quasars with redshifts. We find ∼ 10 percent of our sample have FIR properties similar to typical dusty star-forming galaxies at z ∼ 2-3 and a range of SFRs <20-10000 M yr −1 for our sample as a whole. These results are in line with current models of quasar evolution and suggests a coexistence of dust-obscured star formation and AGN activity is typical of most quasars. We do not find a statistically-significant difference in the FIR luminosities of quasars in our sample with a radio excess relative to the radio-infrared correlation. Synchrotron emission is found to dominate at FIR wavelengths for < 15 percent of those sources classified as powerful radio galaxies.

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“…In addition, strong lensing gives magnified views of background objects otherwise inaccessible to observations (e.g., Impellizzeri et al 2008;Swinbank et al 2009;Richard et al 2011;Deane et al 2013;Treu et al 2015;Mason et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Finding strong gravitational lenses in the Kilo Degree Survey with Convolutional Neural Networks

Petrillo

Tortora

Chatterjee

et al. 2017

Monthly Notices of the Royal Astronomical Society

176

268

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The volume of data that will be produced by new-generation surveys requires automatic classification methods to select and analyze sources. Indeed, this is the case for the search for strong gravitational lenses, where the population of the detectable lensed sources is only a very small fraction of the full source population. We apply for the first time a morphological classification method based on a Convolutional Neural Network (CNN) for recognizing strong gravitational lenses in 255 square degrees of the Kilo Degree Survey (KiDS), one of the current-generation optical wide surveys. The CNN is currently optimized to recognize lenses with Einstein radii > ∼ 1.4 arcsec, about twice the r-band seeing in KiDS. In a sample of 21789 colour-magnitude selected Luminous Red Galaxies (LRG), of which three are known lenses, the CNN retrieves 761 strong-lens candidates and correctly classifies two out of three of the known lenses. The misclassified lens has an Einstein radius below the range on which the algorithm is trained. We down-select the most reliable 56 candidates by a joint visual inspection. This final sample is presented and discussed. A conservative estimate based on our results shows that with our proposed method it should be possible to find ∼ 100 massive LRG-galaxy lenses at z ∼ < 0.4 in KiDS when completed. In the most optimistic scenario this number can grow considerably (to maximally ∼2400 lenses), when widening the colour-magnitude selection and training the CNN to recognize smaller image-separation lens systems.

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The preferentially magnified active nucleus in IRAS F10214+4724 – III. VLBI observations of the radio core

Cited by 15 publications

References 103 publications

Self-consistent two-phase AGN torus models

Self-consistent two-phase AGN torus models

Gravitational lensing reveals extreme dust-obscured star formation in quasar host galaxies

Finding strong gravitational lenses in the Kilo Degree Survey with Convolutional Neural Networks

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