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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 remnant phase of a radio galaxy begins when the jets launched from an active galactic nucleus are switched off. To study the fraction of radio galaxies in a remnant phase, we take advantage of a $8.31$\,deg$^2$ sub-region of the…

Radio galaxy remnants are a rare subset of the radio-loud active galactic nuclei (RLAGN) population, representing the quiescent phase in the RLAGN lifecycle. Despite their observed scarcity, they offer valuable insights into the AGN duty…

We examine the processes triggering star formation and Active Galactic Nucleus (AGN) activity in a sample of 25 low redshift ($z<0.13$) gas-rich galaxy mergers observed at milli-arcsecond resolution with Very Long Baseline Interferometry as…

Astrophysics of Galaxies · Physics 2016-10-12 Stanislav Shabala , Adam Deller , Sugata Kaviraj , Enno Middelberg , Ross Turner , Yuan-Sen Ting , James Allison , Tim Davis

High redshift active galactic nuclei (AGN) provide key insights into early supermassive black hole growth and cosmic evolution. This study investigates the parsec-scale properties of 86 radio-loud quasars at z $\geq$ 3 using very long…

High Energy Astrophysical Phenomena · Physics 2025-02-24 Shaoguang Guo , Tao An , Yuanqi Liu , Chuanzeng Liu , Zhijun Xu , Yulia Sotnikova , Timur Mufakharov , Ailing Wang

Double-double radio galaxies (DDRGs) represent a short but unique phase in the life-cycle of some of the most powerful radio-loud active galactic nuclei (RLAGN). These galaxies display large-scale remnant radio plasma in the intergalactic…

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

That jetted active galactic nuclei (AGN) are also hosted in spiral galaxies is now well established. Our understanding of how such objects might fit in the radio loud AGN subclass has been described by Foschini and others over the past…

High Energy Astrophysical Phenomena · Physics 2023-06-21 Chandra B. Singh , David Garofalo

The core of the nearby galaxy NGC660 has recently undergone a spectacular radio outburst; using a combination of archival radio and Chandra X-ray data, together with new observations, the nature of this event is investigated. Radio…

Astrophysics of Galaxies · Physics 2015-08-06 Megan Argo , Ilse van Bemmel , Sam Connolly , Robert Beswick

Infrared-faint radio sources (IFRS) form a new class of galaxies characterised by radio flux densities between tenths and tens of mJy and faint or absent infrared counterparts. It has been suggested that these objects are radio-loud active…

Although the continua of radio-loud Active Galactic Nuclei (AGN) are typically dominated by synchrotron radiation over virtually the entire spectrum, it is not clear whether the radio and higher-frequency emission originate in the same or…

Astrophysics of Galaxies · Physics 2009-02-06 J. C. Algaba , D. C. Gabuzda , P. S. Smith

We present four Mpc-sized radio galaxies which consist of a pair of double-lobed radio sources, aligned along the same axis, and with a coinciding radio core. We have called these peculiar radio sources `double-double' radio galaxies (DDRG)…

Locating the exact point of origin of the core radiation in active galactic nuclei (AGN) would represent important progress in our understanding of physical processes in the central engine of these objects. However, due to our inability to…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-23 M. B. Bell , S. P. Comeau

We analyze the results of processing of data of observations which had been carried out with the VLBA during 10 last years. All the data have been retrieved from archive of the National Radio Astronomy Observatory (USA NRAO, Socorro, New…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-06 A. Chuprikov , I. Guirin

Low-power radio sources dominate the radio sky. They tend to be small in size and core-dominated, but the origin of their properties and the evolution of their radio plasma are not well constrained. Interestingly, there is mounting evidence…

Astrophysics of Galaxies · Physics 2020-02-19 Sarrvesh S. Sridhar , Raffaella Morganti , Kristina Nyland , Bradley S. Frank , Jeremy Harwood , Tom Oosterloo

Powerful radio galaxies at high redshift are highly useful in studies of early evolution of AGN-hosting galaxies because their observed optical and near infrared light are dominated by their stellar population rather than the nonthermal…

Astrophysics · Physics 2008-11-26 Yoshiaki Taniguchi

We present a model for the inverted radio spectra of active active galactic nuclei as well as the central regions of normal galaxies. The model is based on the unified scenario for active galaxies, stating that the central engines of active…

Astrophysics · Physics 2007-05-23 M. Boettcher , H. -P. Reuter , H. Lesch

A search of large, HI-rich disk galaxies finds a significantly higher fraction of low luminosity AGN signatures compared to other late-type galaxies. Approximately half of the galaxies selected in this sample have AGN-like behavior in their…

Astrophysics · Physics 2007-05-23 James Schombert

Low-luminosity active galactic nuclei (LLAGNs) often host weak radio jets whose propagation is shaped by the surrounding interstellar medium. We investigate the nearby LLAGN NGC7213 to assess its ability to launch collimated outflows beyond…

Astrophysics of Galaxies · Physics 2026-05-12 G. Bruni , F. Panessa , E. Kammoun , A. L. Thakur , C. Reynolds , R. Ricci , M. Wieringa , S. Bianchi , A. De Rosa , G. Matt , F. Nicastro , F. Ursini

We have formed a new sample which consists of extended extragalactic radio sources without obvious active galactic nuclei (AGN) in them. Most of these sources appear to be dead double radio sources. These sources with steep spectra ($\alpha…

Astrophysics of Galaxies · Physics 2011-02-11 K. S. Dwarakanath , Ruta Kale
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