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Related papers: The AGN Component in Deep Radio Fields: Current Un…

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We select a sample of radio galaxies at high redshifts (z>~1) in the COSMOS field, by cross-matching optical/infrared images with the FIRST radio data. The aim of this study is to explore the high-z radio-loud (RL) AGN population at much…

Astrophysics of Galaxies · Physics 2014-09-05 Ranieri D. Baldi , Alessandro Capetti , Marco Chiaberge , Annalisa Celotti

We present a catalogue of local ($z<0.1$) galaxies that contain faint AGN. We select these objects by identifying galaxies that exhibit a significant excess in their radio luminosities, compared to what is expected from the observed levels…

Astrophysics of Galaxies · Physics 2018-06-06 E. K. Lofthouse , S. Kaviraj , D. J. B. Smith , M. J. Hardcastle

Typical blazars seem to be associated with FR I and FR II radio galaxies and radio-loud quasars. However, what happens at lower powers? Do blazars exist in low-luminosity AGN or do they exist in radio-quiet AGN? A recent detection of…

Astrophysics · Physics 2007-05-23 Heino Falcke , Sera Markoff , Peter L. Biermann

We have found empirically that the radio loudness of AGN can be understood as function of both the X-ray and optical luminosity. This way of considering the radio loudness was inspired by the hardness-intensity diagrams for X-ray binaries,…

Astrophysics · Physics 2008-11-26 Sebastian Jester , Elmar Koerding , Rob Fender

We examine the relationship between star formation and AGN activity by constructing matched samples of local ($0<z<0.6$) radio-loud and radio-quiet AGN in the $\textit{Herschel}$-ATLAS fields. Radio-loud AGN are classified as…

Astrophysics of Galaxies · Physics 2015-08-19 G. Gurkan , M. J. Hardcastle , M. J. Jarvis , D. J. B. Smith , N. Bourne , L. Dunne , S. Maddox , R. J. Ivison , J. Fritz

Dark matter haloes in which galaxies reside are likely to have a significant impact on their evolution. We investigate the link between dark matter haloes and their constituent galaxies by measuring the angular two-point correlation…

Astrophysics of Galaxies · Physics 2017-12-27 C. L. Hale , M. J. Jarvis , I. Delvecchio , P. W. Hatfield , M. Novak , V. Smolcic , G. Zamorani

We review the latest attempts to determine the accretion geometry in radio-loud active galactic nuclei (AGN). These objects, which comprise ~10-20% of the AGN population, produce powerful collimated radio jets that can extend thousands of…

Astrophysics · Physics 2008-11-26 D. R. Ballantyne

We investigate the radio emission of ~185,000 quiescent (optically unclassifiable) galaxies selected from the Sloan Digital Sky Survey (SDSS). By median-stacking FIRST cutouts centered on the optically-selected sources, we are able to reach…

Astrophysics · Physics 2009-11-13 J. A. Hodge , R. H. Becker , R. L. White , W. H. de Vries

Despite the plethora of deep (sub-mJy) radio surveys there remains considerable doubt as to the exact nature of the galaxies contributing to the source counts. Current evidence suggests that starformation in moderately luminous 'normal'…

Astrophysics · Physics 2009-11-11 Nick Seymour , Derek Moss , Ian McHardy , Katherine Gunn , Mat Page , Nic Loaring , Tom Dwelly

Until recently, VLBI targets have been drawn almost exclusively from the brightest and most compact radio sources in the sky, with typical flux densities well in excess of a few tens of mJy. These sources are predominantly identified with…

Astrophysics · Physics 2007-05-23 M. A. Garrett

Radio AGN in the nearby Universe are more likely to be found in galaxies with early-type morphology, the detection rate in spiral or late-type galaxies (LTGs) being around an order of magnitude lower. We combine the mJy Imaging VLBA…

Astrophysics of Galaxies · Physics 2015-10-14 Sugata Kaviraj , Stanislav S. Shabala , Adam T. Deller , Enno Middelberg

Using empty-field `Quick Look' images from the first two epochs of the VLA Sky Survey (VLASS) observations, centred on the positions of $\sim3700$ individually radio-non-detected active galactic nuclei (AGNs) at $z\ge4$, we performed image…

Astrophysics of Galaxies · Physics 2023-11-03 Krisztina Perger , Sándor Frey , Krisztina É. Gabányi

The central nuclei of galaxies, where super-massive black holes (SMBHs) are thought to reside, can experience phases of activity when they become Active Galactic Nuclei (AGN). An AGN can eject winds, jets, and produce radiation across the…

Astrophysics of Galaxies · Physics 2019-02-18 Francesca Panessa , Ranieri D. Baldi , Ari Laor , Paolo Padovani , Ehud Behar , Ian McHardy

By combining the 2-degree Field Galaxy Redshift Survey with the NRAO VLA Sky Survey at 1.4 GHz, the environments of radio loud AGN in the nearby Universe are investigated using both local projected galaxy densities and a friends-of-friends…

Astrophysics · Physics 2009-11-10 P. N. Best

A thorough study of radio emission in Active Galactic Nuclei (AGN) is of fundamental importance to understand the physical mechanisms responsible for the emission and the interplay between accretion and ejection processes. High frequency…

Astrophysics of Galaxies · Physics 2020-05-27 E. Chiaraluce , F. Panessa , G. Bruni , R. D. Baldi , E. Behar , F. Vagnetti , F. Tombesi , I. McHardy

A global understanding of Active Galactic Nuclei (AGN) and their host galaxies hinges on completing a census of AGN activity without selection biases down to the low-luminosity regime. Toward that goal, we identify AGN within faint radio…

Astrophysics of Galaxies · Physics 2020-10-14 Stacey Alberts , Wiphu Rujopakarn , George Rieke , Preshanth Jagannathan , Kristina Nyland

Several problems regarding the process of galaxy formation are still open. One of them is the role played by AGN phenomena in contributing to galaxy build-up and to Star Formation (SF) quenching. On the other hand, the theory of AGN…

Astrophysics of Galaxies · Physics 2015-04-15 Nicola Malavasi , Sandro Bardelli , Paolo Ciliegi , Olivier Ilbert , Lucia Pozzetti , Elena Zucca

Radio observations allow us to identify a wide range of active galactic nuclei (AGN), which play a significant role in the evolution of galaxies. Amongst AGN at low radio-luminosities is the 'radio-quiet' quasar (RQQ) population, but how…

We investigate faint radio emission from low- to high-luminosity Active Galactic Nuclei (AGN) selected from the Sloan Digital Sky Survey (SDSS). Their radio properties are inferred by co-adding large ensembles of radio image cut-outs from…

Astrophysics · Physics 2008-11-26 W. H. de Vries , J. A. Hodge , R. H. Becker , R. L. White , D. J. Helfand

We present a study of a 20cm selected sample in the Deep SWIRE VLA Field, reaching a limiting flux density of ~13.5 uJy at the image center. In a 0.6x0.6 square degrees field, we are able to assign an optical/IR counterpart to 97% of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Veronica Strazzullo , Maurilio Pannella , Frazer N. Owen , Ralf Bender , Glenn E. Morrison , Wei-Hao Wang , David L. Shupe