English
Related papers

Related papers: Exploring AGN Activity over Cosmic Time with the S…

200 papers

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

It is well-known that star-forming galaxies (SFGs) exhibit a tight correlation between their radio and infrared emissions, commonly referred to as the infrared-radio correlation (IRRC). Recent empirical studies have reported a dependence of…

How does the environment affect active galactic nucleus (AGN) activity? We investigated this question in an extinction-free way, by selecting 1120 infrared galaxies in the $AKARI$ North Ecliptic Pole Wide field at redshift $z$ $\leq$ 1.2. A…

This paper presents the first measurement of the radio luminosity function of 'jet-mode' (radiatively-inefficient) radio-AGN out to z=1, in order to investigate the cosmic evolution of radio-AGN feedback. Eight radio source samples are…

Astrophysics of Galaxies · Physics 2015-06-22 P. N. Best , L. M. Ker , C. Simpson , E. E. Rigby , J. Sabater

We present an exploration of the expected detection of the earliest Active Galactic Nuclei (AGN) in the Universe from state-of-art galaxy formation and evolution semi-analytic models and hydro-dynamical simulations. We estimate the number…

In a series of papers based on the FIRST and Sloan Digital Sky Surveys (SDSS), we investigate the local population of star-forming galaxies and Active Galactic Nuclei (AGN) in order to clarify the link between these two types of activity,…

Cosmology and Nongalactic Astrophysics · Physics 2009-03-25 Pietro M. Reviglio , David J. Helfand

Exploring how radio-emitting active galactic nuclei (AGN) behave and evolve with time is critical for understanding how AGN feedback impacts galaxy evolution. In this work, we investigate the relationship between 1.4 GHz radio continuum AGN…

Active galactic nuclei (AGN) are known for irregular variability on all time scales, down to intra-day variability with relative variations of a few percent within minutes to hours. On such short timescales, unexplored territory, such as…

Astrophysics of Galaxies · Physics 2015-11-27 Taeseok Lee , Sascha Trippe , Junghwan Oh , Do-Young Byun , Bong-Won Sohn , Sang-Sung Lee

We explore the use of SKA to deduce the physical parameters of kiloparsec-scale jet flows in radio galaxies. Jets in Active Galactic Nuclei are relativistic where they are first formed, but their speeds and compositions change as they…

Astrophysics of Galaxies · Physics 2015-01-05 R. A. Laing

The present paper reviews our current understanding of the AGN component in sub-mJy radio fields, as it results from the exploitation of multi-frequency information available in two deep extra-galactic radio fields: the ATESP 5 GHz sample…

Cosmology and Nongalactic Astrophysics · Physics 2010-08-31 Isabella Prandoni

The survey of the COSMOS field by the VLT Survey Telescope is an appealing testing ground for variability studies of active galactic nuclei (AGN). With 54 r-band visits over 3.3 yr and a single-visit depth of 24.6 r-band mag, the dataset is…

Astrophysics of Galaxies · Physics 2021-01-27 D. De Cicco , F. E. Bauer , M. Paolillo , S. Cavuoti , P. Sánchez-Sáez , W. N. Brandt , G. Pignata , M. Vaccari , M. Radovich

Activity at the centers of galaxies, during which the central supermassive black hole is accreting material, is nowadays accepted to be rather ubiquitous and most probably a phase of every galaxy's evolution. It has been suggested that…

We use ultradeep 20 cm data from the Karl G. Jansky Very Large Array and 850 micron data from SCUBA-2 and the Submillimeter Array of an 124 arcmin^2 region of the Chandra Deep Field-north to analyze the high radio power (P_20cm>10^31 erg…

Astrophysics of Galaxies · Physics 2017-02-15 Amy J. Barger , Lennox L. Cowie , Frazer N. Owen , Li-Yen Hsu , Wei-Hao Wang

We present preliminary results of a study of the low frequency radio continuum emission from the nuclei of Giant Low Surface Brightness (LSB) galaxies. We have mapped the emission and searched for extended features such as radio lobes/jets…

Astrophysics · Physics 2009-11-13 M. Das , S. S. McGaugh , N. Kantharia , S. N. Vogel

The energy released by AGN has the potential to heat or remove the gas of the ISM, thus likely impacting the cold molecular gas reservoir of host galaxies at first, with star formation following on longer timescales. Previous works on…

With the low Earth orbit environment becoming increasingly populated with artificial satellites, rockets, and debris, it is important to understand the effects they have on radio astronomy. In this work, we undertake a multi-frequency,…

Earth and Planetary Astrophysics · Physics 2025-01-29 Dylan Grigg , Steven Tingay , Steve Prabu , Marcin Sokolowski , Balthasar Indermuehle

Most of the Active Galactic Nuclei (AGN) are radio-quiet (RQ) and, differently from radio-loud (RL) AGN, do not show signature of large-scale and powerful jets. The physical origin of their radio emission remains then broadly unclear. The…

High Energy Astrophysical Phenomena · Physics 2023-09-06 P. O. Petrucci , V. Piétu , E. Behar , M. Clavel , S. Bianchi , G. Henri , S. Barnier , S. Chen , J. Ferreira , J. Malzac , R. Belmont , S. Corbel , M. Coriat

Radio observations allow us to identify a wide range of active galactic nuclei (AGN), which are galaxies that have gas accreting onto the supermassive black-hole at the centre. By observing these sources at multiple radio frequencies, a…

Astrophysics of Galaxies · Physics 2023-07-19 Sarah V. White

Recent deep and wide radio surveys extend the studies for radio-excess active galactic nuclei (radio-AGNs) to lower luminosities and higher redshifts, providing new insights into the abundance and physical origin of radio-AGNs. Here we…

The properties of the host galaxies of a well-defined sample of 2215 radio-loud AGN with redshifts 0.03 < z < 0.3, defined from the SDSS, are investigated. These are predominantly low radio luminosity sources, with 1.4GHz luminosities of…

Astrophysics · Physics 2008-11-26 P. N. Best , G. Kauffmann , T. M. Heckman , J. Brinchmann , S. Charlot , Z. Ivezic , S. D. M. White