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Related papers: Are young radio sources in equipartition?

200 papers

We present radio spectra spanning $0.1 - 10$ GHz for the sample of heavily obscured luminous quasars with extremely red mid-infrared-optical colors and compact radio emission. The spectra are constructed from targeted 10 GHz observations…

Due to their steep spectra, low-frequency observations of FR II radio galaxies potentially provide key insights in to the morphology, energetics and spectrum of these powerful radio sources. However, limitations imposed by the previous…

We have made deep Chandra observations of three powerful FRII radio sources: two quasars (3C263 and 3C351) and one radio galaxy (3C330). X-ray emission from hotspots and lobes, as well as from the active nucleus, is detected in each source.…

Follow-up studies of persistent emission from fast radio burst (FRB) sources are critical for understanding their elusive emission mechanisms and the nature of their progenitors. This work presents new observations of the persistent radio…

High Energy Astrophysical Phenomena · Physics 2025-12-05 Arvind Balasubramanian , Mohit Bhardwaj , Shriharsh P. Tendulkar

The commonly used classical equipartition or minimum-energy estimate of total magnetic fields strengths from radio synchrotron intensities is of limited practical use because it is based on the hardly known ratio K of the total energies of…

Astrophysics · Physics 2007-05-23 Rainer Beck , Marita Krause

By combining high-sensitivity LOFAR 150MHz, uGMRT 400MHz and 1,250MHz, GMRT 610MHz, and VLA 5GHz data in the ELAIS-N1 field, we study the radio spectral properties of radio-detected star-forming galaxies (SFGs) at observer-frame frequencies…

We present high-resolution radio observations of a sample of 65 radio sources at low Galactic latitudes. The sources were all observed at 5 GHz with the Very Large Array A-array. MERLIN observations at 5 GHz of the ultracompact HII region…

Astrophysics · Physics 2009-11-10 D. J. Saikia , P. Thomasson , S. Roy , A. Pedlar , T. W. B. Muxlow

[Abridged] Physical and evolutionary properties of the sub-mJy radio population are not entirely known. The radio/optical analysis of the ATESP 5 GHz sample has revealed a significant class of compact flat/inverted radio-spectrum sources…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 I. Prandoni , H. R. de Ruiter , R. Ricci , P. Parma , L. Gregorini , R. D. Ekers

Here we present a sample of sources with convex radio spectra peaking at frequencies above a few GHz. We call these radio sources High Frequency Peakers (HFPs). This sample extends to higher turnover frequencies than the samples of Compact…

Astrophysics · Physics 2016-08-30 Daniele Dallacasa , Carlo Stanghellini , Matteo Centonza , Roberto Fanti

We present VLBA 1.6, 5, 8.4 and 15 GHz observations of a new sample of weak, young, compact candidates for radio faders selected from the VLA FIRST survey. We claim that some, or even the majority of young sources, may be short-lived…

Astrophysics · Physics 2007-05-23 M. Kunert-Bajraszewska , A. Marecki , R. E. Spencer

We present radio observations at 1.5 GHz of 32 local objects selected to reproduce the physical properties of $z\sim5$ star-forming galaxies. We also report non-detections of five such sources in the sub-millimetre. We find a radio-derived…

Astrophysics of Galaxies · Physics 2017-06-28 Stephanie M. L. Greis , Elizabeth R. Stanway , Andrew J. Levan , Luke J. M. Davies , J. J. Eldridge

In this paper we study two newly discovered classes of radio sources: the highly energetic, short-lived events, known as Fast Radio Bursts (FRBs), and a new category of compact sources known as Fanaroff-Riley type 0 radio galaxies (FR0s).…

Astrophysics of Galaxies · Physics 2019-12-11 Sergio Best , José Bazo

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…

We associate the existence of short-lived compact radio sources with the intermittent activity of the central engine caused by a radiation pressure instability within an accretion disk. Such objects may constitute a numerous sub-class of…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 Bozena Czerny , Aneta Siemiginowska , Agnieszka Janiuk , Blazej Nikiel-Wroczynski , Lukasz Stawarz

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

Most of the Universe's populations of low energy cosmic ray electrons in the energy range of 1-100 MeV still manage to elude from detection by our instruments, since their synchrotron emission is at too low frequencies. We investigate a…

Astrophysics · Physics 2009-11-06 Torsten A. Ensslin , Rashid A. Sunyaev

Compact steep-spectrum radio sources and giga-hertz peaked spectrum radio sources (CSS/GPS) are generally considered to be mostly young radio sources. In recent years we studied at many wavelengths a sample of these objects selected from…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 C. Fanti , R. Fanti , A. Zanichelli , D. Dallacasa , C. Stanghellini

We present new high spatial resolution VLT and VLA observations of a sample of nine low-power (P_{1.4 GHz} < 10^{25} W/Hz) radio hotspots. Infrared/optical emission is definitely detected in four of the nine observed objects, resulting in a…

Astrophysics · Physics 2009-11-13 K. -H. Mack , M. A. Prieto , G. Brunetti , M. Orienti

Multifrequency observations with the GMRT and the VLA are used to determine the spectral breaks in consecutive strips along the lobes of a sample of selected giant radio sources (GRSs) in order to estimate their spectral ages. The maximum…

Cosmology and Nongalactic Astrophysics · Physics 2009-05-05 C. Konar , D. J. Saikia , M. Jamrozy , J. Machalski

Radio galaxies with a projected linear size > 1 Mpc are classified as giant radio sources. According to the current interpretation these are old sources which have evolved in a low-density ambient medium. Since radiative losses are…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 E. Orrù , M. Murgia , L. Feretti , F. Govoni , G. Giovannini , W. Lane , N. Kassim , R. Paladino