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Peaked-spectrum (PS) sources, known for their distinct peaked radio spectra, represent a type of radio-loud active galactic nuclei (AGN). Among these, megahertz-peaked spectrum (MPS) sources, which exhibit a spectral peak at a frequency of…

We present a 324.5MHz image of the NOAO Bo\"otes field that was made using Very Large Array (VLA) P-band observations. The image has a resolution of 5.6x5.1arcsec, a radius of $2.05^\circ$ and a central noise of ~0.2mJy\beam. Both the…

Astrophysics of Galaxies · Physics 2015-04-01 Rocco Coppejans , David Cseh , Wendy L. Williams , Sjoert van Velzen , Heino Falcke

We present a sample of 1,483 sources that display spectral peaks between 72 MHz and 1.4 GHz, selected from the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey. The GLEAM survey is the widest fractional bandwidth…

Extragalactic peaked-spectrum radio sources are thought to be the progenitors of larger, radio-loud active galactic nuclei (AGN). Synchrotron self-absorption (SSA) has often been identified as the cause of their spectral peak. The…

Astrophysics of Galaxies · Physics 2019-08-07 M. A. Keim , J. R. Callingham , H. J. A. Röttgering

Recent sensitive wide-field radio surveys, such as the LOFAR Two Meter Sky Survey (LoTSS), the LOFAR LBA Sky Survey (LoLSS), and the Very Large Array Sky Survey (VLASS), enable the selection of statistically large samples of peaked-spectrum…

Astrophysics of Galaxies · Physics 2024-09-25 F. J. Ballieux , J. R. Callingham , H. J. A. Röttgering , M. M. Slob

Gigahertz-Peaked spectrum (GPS) sources are compact active galactic nuclei, presumably young precursors of bright radio sources. The study of GPS radio properties provides information about the features of synchrotron radiation in…

Astrophysics of Galaxies · Physics 2020-01-08 Yu. Sotnikova , T. Mufakharov , E. Majorova , M. Mingaliev , R. Udovitskiy , N. Bursov , T. Semenova

We report the radio continuum properties for several samples of peaked spectrum (PS) radio sources. Broadband spectra of the objects were analysed using the RATAN-600 six-frequency (1.2-22 GHz) observations and available literature data,…

Astrophysics of Galaxies · Physics 2021-11-10 Yu. Sotnikova , T. Mufakharov , M. Mingaliev , A. Mikhailov

There is now strong evidence that many low-luminosity AGNs (LLAGNs) contain accreting massive black holes and that the nuclear radio emission is dominated by parsec-scale jets launched by these black holes. Here, we present preliminary…

Astrophysics · Physics 2007-05-23 N. M. Nagar , A. S. Wilson , H. Falcke , J. S. Ulvestad , C. G. Mundell

The study of compact active galactic nuclei (AGN) that possess convex radio spectra (the gigahertz-peaked spectrum radio sources) offers a unique opportunity to probe both the early evolutionary stages of relativistic AGN jets and their…

Astrophysics · Physics 2007-05-23 M. L. Lister

Gigahertz Peaked Spectrum (GPS) sources form a key element in the study of the onset and evolution of radio-loud AGN, since they are most likely the young counterparts of extended radio sources. Here we discuss space-VLBI observations of…

We present the data and analysis of VLBI observations at 1.6, 5 and 15 GHz of a sample of faint Gigahertz Peaked Spectrum (GPS) sources selected from the Westerbork Northern Sky Survey (WENSS). The 5 GHz observations involved a global array…

Astrophysics · Physics 2016-08-30 Ignas Snellen , Richard Schilizzi , Huib-Jan van Langevelde

Compact steep-spectrum (CSS) and peaked spectrum (PS) radio sources are compact, powerful radio sources. The multi-frequency observational properties and current theories are reviewed with emphasis on developments since the earlier review…

Astrophysics of Galaxies · Physics 2021-04-07 Christopher P. O'Dea , D. J. Saikia

Observations with MERLIN at 408 MHz have been used to establish the low-frequency part of the spectra of more than a hundred compact radio sources taken from the part of the Jodrell Bank--VLA Astrometric Survey limited by 35 deg. < \delta <…

Astrophysics · Physics 2015-06-24 A. Marecki , H. Falcke , J. Niezgoda , S. T. Garrington , A. R. Patnaik

High-redshift quasars are important to study galaxy and active galactic nuclei (AGN) evolution, test cosmological models, and study supermassive black hole growth. Optical searches for high-redshift sources have been very successful, but…

High-redshift radio-loud quasars are used to, among other things, test the predictions of cosmological models, set constraints on black hole growth in the early universe and understand galaxy evolution. Prior to this paper, 20 extragalactic…

Gigahertz Peaked Spectrum (GPS) radio galaxies are generally thought to be the young counterparts of classical extended radio sources. Statistically complete samples of GPS sources are vital for studying the early evolution of radio-loud…

Astrophysics · Physics 2009-11-13 N. de Vries , I. A. G. Snellen , R. T. Schilizzi , M. D. Lehnert , M. N. Bremer

Characterising spectral variability of radio sources is a technique that offers the ability to determine the astrophysics of the intervening media, source structure, emission and absorption processes. We present broadband (0.072--10 GHz)…

Astrophysics of Galaxies · Physics 2022-04-06 K. Ross , N. Hurley-Walker , N. Seymour , J. R. Callingham , T. J. Galvin , M. Johnston-Hollitt

In this work, we study the optical properties of compact radio sources selected from the literature in order to determine the impact of the radio-jet in their circumnuclear environment. Our sample includes 58 Compact Steep Spectrum (CSS)…

In the time domain, the radio sky in particular along the Galactic plane direction may vary significantly because of various energetic activities associated with stars, stellar and supermassive black holes. Using multi-epoch Very Large…

High Energy Astrophysical Phenomena · Physics 2022-01-12 Jun Yang , Yongjun Chen , Leonid I. Gurvits , Zsolt Paragi , Aiyuan Yang , Xiaolong Yang , Zhiqiang Shen

We have carried out a detailed study of the spectral nature of six pulsars surrounded by Pulsar wind nebulae (PWN). The pulsar flux density were estimated using the interferometric imaging technique of the Giant Metrewave Radio Telescope at…

High Energy Astrophysical Phenomena · Physics 2018-02-07 Rahul Basu , Karolina Rożko , Jarosław Kijak , Wojciech Lewandowski
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