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Compact symmetric objects (CSOs) trace the earliest phases of radio-galaxy growth; however, robust classification is difficult when radio cores are weak or invisible. We aim to develop and test a Gaia+VLBI approach that utilizes the…

Astrophysics of Galaxies · Physics 2026-01-14 T. An , Y. Zhang , S. Frey , W. A. Baan , A. Wang

We present a series of sixteen Very Long Baseline Array (VLBA) high angular resolution observations of a cluster of suspected low-mass young stars in the Monoceros R2 region. Four compact and highly variable radio sources are detected;…

We investigate the spectral characteristics of 51 candidate High Frequency Peakers (HFPs), from the ``bright'' HFP sample, in order to determine the nature of each object, and to obtain a smaller sample of genuine young radio sources.…

Astrophysics · Physics 2009-11-13 M. Orienti , D. Dallacasa , C. Stanghellini

We present pc-scale images of ten Compact Symmetric Objects (CSO) candidates observed with the European VLBI network (EVN). Five radio sources have been observed at 1.6 GHz, and five more at 2.3/8.4 GHz, the latter subsample with the…

Astrophysics · Physics 2009-11-07 Liu Xiang , Carlo Stanghellini , Daniele Dallacasa , Zhang Haiyan

We present optical identifications and radio spectra for ten radio sources from two flux-density-complete samples. Radio variability characteristics are presented for four objects. The observations were obtained on the RATAN-600 radio…

Astrophysics · Physics 2009-11-07 V. Chavushyan , R. Mujica , A. G. Gorshkov , V. K. Konnikova , M. G. Mingaliev , J. R. Valdez

A small sample of 7 southern Compact Steep Spectrum (CSS) radio sources has been selected as part of the study of a larger flux-limited complete sample of radio sources. High resolution images, using the VLBI network in the southern…

Aims - We report new Very Large Array polarimetric observations of Compact Steep-Spectrum (CSS) sources at 8.4, 15, and 23GHz. Methods - Using multi-frequency VLA observations we have derived sub-arcsecond resolution images of the total…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 F. Mantovani , A. Rossetti , W. Junor , D. J. Saikia , C. J. Salter

We present VLBA observations at 15 GHz of ten GHz Peaked Spectrum (GPS) radio sources. The cores are often difficult or impossible to locate. When likely cores are found, they account for a small fraction of the flux density in GPS galaxies…

Astrophysics · Physics 2009-11-07 C. Stanghellini , D. Dallacasa , C. P. O'Dea , S. A. Baum , R. Fanti , C. Fanti

We present results on global very long baseline interferometry (VLBI) observations at 327 MHz of eighteen compact steep-spectrum (CSS) and GHz-peaked spectrum (GPS) radio sources from the 3C and the Peacock & Wall catalogues. About 80 per…

Astrophysics of Galaxies · Physics 2021-05-12 D. Dallacasa , M. Orienti , C. Fanti , R. Fanti

The evolution of symmetric extragalactic radio sources can be characterized by four distinct growth stages of the radio luminosity versus size of the source. The interaction of the jet with the ambient medium results in the formation and…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-09 Tao An , Willem A. Baan

Short time-scale flux density variations of flat spectrum radio sources are often explained by the scattering of radio waves in the turbulent, ionized Interstellar Matter of the Milky Way. One of the most convincing observational arguments…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-26 K. E. Gabanyi , N. Marchili , T. P. Krichbaum , L. Fuhrmann , P. Muller , J. A. Zensus , X. Liu , H. G. Song

In order to understand the origin and evolution of radio galaxies, searches for the youngest such sources have been conducted. Compact-medium symmetric objects (CSO-MSOs) are thought to be the earliest stages of radio sources, with possible…

Among more than 800 known fast radio bursts (FRBs), only two, namely FRB 20121102A and FRB 20190520B, are confirmed to be associated with a persistent radio sources (PRS). Here we report evidence of apparent temporal variability in the PRS…

We present the results of a program to monitor the structure of the radio emission in 42 $\gamma$-ray bright blazars (31 quasars and 11 BL Lac objects) with the VLBA at 43, 22, and occasionally 15 and 8.4 GHz, over the period from November…

We present the results of Karl G. Jansky Very Large Array (VLA) observations to study the properties of FR0 radio galaxies, the compact radio sources associated with early-type galaxies which represent the bulk of the local radio-loud AGN…

Astrophysics of Galaxies · Physics 2018-11-28 Ranieri D. Baldi , Alessandro Capetti , Gabriele Giovannini

We defined a sub-sample of twelve GPS sources which have not been observed with the VLBI before, from the Parkes half-Jansky sample, and carried out VLBI observations at 1.6 GHz and 5 GHz with the European VLBI Network (EVN) in 2006 and…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-25 L. Cui , X. Liu , J. Liu , H. -G. Song , Z. Ding

We report the results of multifrequency-VLBI observations of GHz-Peaked-Spectrum (GPS) radio sources. The VLBI structure and component spectra of some GPS sources are presented. Our VLBI results show that about 80% of the GPS galaxies…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-20 X. Liu , H. -G Song , L. Cui

We have obtained 8.4 GHz VLBA observations of a 31-GHz complete sample of ~100 sources between 10 and 100 mJy. The main goals of these observations are: to determine the angular size, radio spectra and identification for a weak sample of…

Astrophysics · Physics 2008-06-19 W. A. Majid , E. B. Fomalont , D. S. Bagri

We show an archival 1.4-GHz Very Large Array (VLA) image of the core-dominated triple (CDT) radio source J1628+3906, along with a recent high-resolution 5-GHz Very Long Baseline Interferometry (VLBI) image of its core. This core is resolved…

Astrophysics · Physics 2009-04-14 D. Cseh , A. Fuhl , S. Frey

We present results of EVN observations of eleven GHz-Peaked-Spectrum (GPS) radio sources at 2.3/8.4 GHz. These sources are from the classical ''bright'' GPS source samples with peak flux densities $>$ 0.2 Jy and spectral indices $\alpha <…

Astrophysics · Physics 2007-05-23 L. Xiang , D. Dallacasa , P. Cassaro , D. Jiang , C. Reynolds