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

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Investigation of the triggering mechanisms of radio AGN is important for improving our general understanding of galaxy evolution. In the first paper in this series, detailed morphological analysis of high-excitation radio galaxies (HERGs)…

We present a brief overview of a very extensive studies of the group of active galactic nuclei (AGNs) that transitioned to radio-loud state over the past few decades. The sample consists of twelve sources, both quasars and galaxies, showing…

The mechanism of radio emission in radio-quiet (RQ) active galactic nuclei (AGN) is still debated and might arise from the central AGN, from star formation activity in the host, or from either of these sources. A direct detection of compact…

Astrophysics of Galaxies · Physics 2016-04-06 Alessandro Maini , Isabella Prandoni , Ray P. Norris , Gabriele Giovannini , Lee R. Spitler

We have analyzed new, archival and published high resolution radio and X-ray observations of a sample of composite LINER/HII galaxies known to exhibit AGN-like properties. Five of the 16 AGN candidates have milliarcsecond-scale detections…

Astrophysics · Physics 2009-11-10 M. E. Filho , F. Fraternali , S. Markoff , N. M. Nagar , P. D. Barthel , L. C. Ho , F. Yuan

We investigate the star formation properties of ~800 sources detected in one of the deepest radio surveys at 1.4 GHz. Our sample spans a wide redshift range (~0.1 - 4) and about four orders of magnitude in star formation rate (SFR). It…

Astrophysics of Galaxies · Physics 2015-09-09 M. Bonzini , V. Mainieri , P. Padovani , P. Andreani , S. Berta , M. Bethermin , D. Lutz , G. Rodighiero , D. Rosario , P. Tozzi , S. Vattakunnel

Only a small fraction of observed Active Galactic Nuclei display large-scale radio emission associated with jets, yet these radio-loud AGN have become increasingly important in models of galaxy evolution. In determining the dynamics and…

I present an introductory review text, focusing on recent deep field studies using radio telescopes, including high-resolution, wide-field VLBI observations. The nature of the faint radio source population is discussed, taking into account…

Astrophysics · Physics 2009-11-10 M. A. Garrett

In order to find more examples of the elusive high-redshift molecular absorbers, we have embarked on a systematic discovery program for highly obscured, radio-loud "invisible AGN" using the VLA Faint Images of the Radio Sky at Twenty…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 T. Yan , J. T. Stocke , J. Darling , F. Hearty

We tested the effectiveness of radio selection to discover heavily obscured AGNs, particularly at high-z, and we measured their abundance for the first time from a radio perspective. We consider the radio sources detected in the J1030…

In this study we investigate 89 radio galaxies that are spectroscopically-confirmed to be members of five large scale structures in the redshift range of $0.65 \le z \le 0.96$. Based on a two-stage classification scheme, the radio galaxies…

We study the radio properties of moderately obscured quasars over a range of redshifts to understand the role of radio activity in accretion using the Jansky Very Large Array (JVLA) at 6.0GHz and 1.4GHz. Our z~2.5 sample consists of…

Astrophysics of Galaxies · Physics 2016-08-31 Rachael M. Alexandroff , Nadia L. Zakamska , Sjoert van Velzen , Jenny E. Greene , Michael A. Strauss

A great deal of interest has been generated recently by the results of deep submillimetre surveys, which in principle allow an unobscured view of dust-enshrouded star formation at high redshift. The extragalactic far-infrared and…

Astrophysics · Physics 2007-05-23 O. Almaini , A. Lawrence , B. J. Boyle

The coevolution of supermassive black holes and their host galaxies represents a fundamental question in astrophysics. One approach to investigating this question involves comparing the star-formation rates (SFRs) of active galactic nuclei…

Astrophysics of Galaxies · Physics 2024-11-26 Bojun Zhang , Fan Zou , W. N. Brandt , Shifu Zhu , Nathan Cristello , Qingling Ni , Yongquan Xue , Zhibo Yu

We report on the investigation of a complete sample of young radio-loud AGN at z<0.25, selected using the new comprehensive radio surveys and the optical APM/POSS-I catalog. This new sample will provide a unique opportunity for statistical…

Astrophysics · Physics 2007-05-23 I. A. G. Snellen , K. -H. Mack , W. Tschager , R. T. Schilizzi

The faint radio-source population includes sources dominated both by star formation and active galactic nuclei (AGN), encoding the evolution of activity in the Universe. To investigate its nature, we probabilistically classified 4,471 radio…

We have conducted 22 GHz 1" JVLA imaging of 70 radio-quiet AGN from the Swift-BAT survey. We find radio cores in all but three objects. The radio morphologies of the sample fall into three groups: compact and core-dominated, extended, and…

Astrophysics of Galaxies · Physics 2016-12-14 Krista Lynne Smith , Richard F. Mushotzky , Stuart Vogel , Thomas T. Shimizu , Neal Miller

There exist strong evidence supporting the co-evolution of central supermassive black holes and their host galaxies. It is however still unclear what the exact role of nuclear activity, in the form of accretion onto these supermassive black…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-17 Marios Karouzos , Markos Trichas , Myungshin Im , Matthew Malkan , the AKARI-NEP team

We use highly spectroscopically complete observations of the radio sources from the VLA 1.4 GHz survey of the HDF-N region to study the faint radio galaxy population and its evolution. We spectrally classify the sources into four spectral…

Astrophysics · Physics 2011-02-11 A. J. Barger , L. L. Cowie , W. -H. Wang

In recent work, we have identified two sub-populations of radio-loud AGN which appear to be distinguished by jet structure, where low-efficiency accreting systems produce `weak' jets which decelerate more rapidly than the `strong' jets of…

High Energy Astrophysical Phenomena · Physics 2012-05-04 Eileen T. Meyer , Giovanni Fossati , Markos Georganopoulos , Matthew L. Lister

We present here a new spectral energy distribution (SED) fitting approach that we adopt to select radio-excess sources amongst distant star-forming galaxies in the GOODS-Herschel (North) field and to reveal the presence of hidden, highly…