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Dual-Active Galactic Nuclei (AGN) are a natural consequence of the hierarchical structure formation scenario, and can provide an important test of various models for black hole growth. However, due to their rarity and difficulty to find at…

Astrophysics of Galaxies · Physics 2021-09-22 C. S. Mangat , J. P. McKean , R. Brilenkov , P. Hartley , H. R. Stacey , S. Vegetti , D. Wen

This paper explores the role of small-scale environment ($<1$ Mpc) in modulating accretion events onto supermassive black holes by studying the incidence of Active Galactic Nuclei (AGN) in massive clusters of galaxies. A flexible,…

The polarization properties of radio sources powered by an Active Galactic Nucleus (AGN) have attracted considerable attention because of the significance of magnetic fields in the physics of these sources, their use as probes of plasma…

Astrophysics of Galaxies · Physics 2021-03-17 Ryan S. Johnston , Jeroen M. Stil , Ben W. Keller

We study the impact of outflows driven by active galactic nuclei (AGN) on galaxy formation. Outflows move into the surrounding intergalactic medium (IGM) and heat it sufficiently to prevent it from condensing onto galaxies. In the dense,…

Astrophysics · Physics 2009-11-13 Evan Scannapieco , Joseph Silk , Rychard Bouwens

We analyze four extreme active galactic nuclei (AGN) transients to explore the possibility that they are caused by rare, high-amplitude microlensing events. These previously unknown type-I AGN are located in the redshift range 0.6-1.1 and…

The role played by the intergalactic medium (IGM) in the X-ray absorption towards high-redshift sources has recently drawn more attention in spectral analysis studies. Here, we study the X-ray absorption towards 15 flat-spectrum radio…

High Energy Astrophysical Phenomena · Physics 2018-09-05 R. Arcodia , S. Campana , R. Salvaterra , G. Ghisellini

We present the results of an analysis of Wide-field Infrared Survey Explorer (WISE) observations on the full 2500 deg^2 South Pole Telescope (SPT)-SZ cluster sample. We describe a process for identifying active galactic nuclei (AGN) in…

Two dozens of radio loud active galactic nuclei (AGNs) have been observed with Urumqi 25 m radio telescope in order to search for intra-day variability (IDV). The target sources are blazars (namely flat spectrum radio quasars and BL Lac…

High Energy Astrophysical Phenomena · Physics 2021-08-23 Xiang Liu , Xin Wang , Ning Chang , Jun Liu , Lang Cui , Xiaofeng Yang , Thomas P. Krichbaum

We use high angular resolution data, measured from visibility of sources at the longest baseline of 4500 m of the Australia Telescope Compact Array (ATCA), for the Australia Telescope 20 GHz (AT20G) survey to obtain angular size information…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 R. Chhetri , R. D. Ekers , E. K. Mahony , P. A. Jones , M. Massardi , R. Ricci , E. M. Sadler

Next-generation radio surveys are expected to detect tens of millions of active galactic nuclei (AGN) with a median redshift of z > 1. Beyond targeted surveys, the vast majority of these objects will not have spectroscopic redshifts, whilst…

Astrophysics of Galaxies · Physics 2020-11-03 Ross J. Turner , Guillaume Drouart , Nick Seymour , Stanislav S. Shabala

We compare a large sample of galaxies between 0.5<z<2.6 with theoretical predictions for how the optical diagnostic line ratios in galaxy ensembles change as a function of cosmic time. We show that star forming galaxies at high redshift…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Lisa J. Kewley , Christian Maier , Kiyoto Yabe , Kouji Ohta , Masayuki Akiyama , Michael A. Dopita , Tiantian Yuan

We present a multi-wavelength study into the nature of faint radio sources in a deep radio image with the Giant Meterwave Radio Telescope at 612\,MHz covering 1.2 deg$^2$ of the ELAIS N1 region. We detect 2800 sources above…

Astrophysics of Galaxies · Physics 2017-04-12 E. F. Ocran , A. R. Taylor , M. Vaccari , D. A. Green

We present a sample of 252 broad-line Active Galactic Nuclei (BLAGNs), incorporating 171 newly identified sources, spanning a redshift interval from $z$ = 0.8 to 7.2. We have analyzed spectroscopic data from the NIRSpec instrument aboard…

Astrophysics of Galaxies · Physics 2025-12-04 Caroline Baccus , Xinfeng Xu

This paper presents a study of the redshift evolution of radio-loud active galactic nuclei (AGN) as a function of the properties of their galaxy hosts in the Bo\"otes field. To achieve this we match low-frequency radio sources from deep…

Active Galactic Nuclei (AGN) are intertwined with galaxy evolution, injecting energy into the interstellar medium (ISM) that could regulate star formation as a galaxy evolves. However, the phenomena through which we observe AGN are…

Radio continuum emission provides a unique opportunity to study star-formation unbiased by dust obscuration. However, if radio observations are to be used to accurately trace star-formation to high redshifts, it is crucial that the physical…

Context. The Australia Telescope Large Area Survey (ATLAS) aims to image a 7 deg2 region centred on the European Large Area ISO Survey - South 1 (ELAIS-S1) field and the Chandra Deep Field South (CDF-S) at 1.4 GHz with high sensitivity (up…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-30 Peter-Christian Zinn , Enno Middelberg , Ray P. Norris , Christopher A. Hales , Minnie Y. Mao , Kate E. Randall

We present Spitzer/IRS mid-infrared spectra for 15 gravitationally lensed, 24 micron--selected galaxies, and combine the results with 4 additional very faint galaxies with IRS spectra in the literature. The median intrinsic 24 micron flux…

We present a study of the incidence of active galactic nucleus (AGN) in a sample of major merging systems at 0.3<z<2.5. Galaxies in this merger sample have projected separations between 3 to 15 kpc and are selected from the CANDELS/3D-HST…