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We study the most central regions of AGN jets with an angular resolution of tens of micro-arcseconds using VLBI at millimeter wavelengths (mm-VLBI). We present and discuss a new 86 GHz VLBI survey of compact radio sources. We show new high…

Astrophysics · Physics 2007-08-30 T. P. Krichbaum , S. S. Lee , A. P. Lobanov , A. P. Marscher , M. A. Gurwell

We have used the VLBA at 15 GHz to image the structure of 132 strong compact AGN and quasars with a resolution better than one milliarcsecond and a dynamic range typically exceeding 1000 to 1. These observations were made as part of a…

Astrophysics · Physics 2009-10-30 K. I. Kellermann , R. C. Vermeulen , J. A. Zensus , M. H. Cohen

We investigated the archival ground-based VLBI images of the extragalactic radio sources included in both the {\it Wilkinson Microwave Anisotropy Probe (WMAP)} and the {\it Planck} catalogues, and selected 49 bright and compact sources as…

Astrophysics of Galaxies · Physics 2015-06-19 Tao An , Xiaocong Wu , Sandor Frey

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 the results of a second epoch of 18cm global Very Long-Baseline Interferometry (VLBI) observations, taken on 23 February 2001, of the central kiloparsec of the nearby starburst galaxy Messier 82. These observations further…

We present the first results from 60ks of observations of Arp 220 using the ACIS-S instrument on Chandra. We report the detection of several sources near the galaxy's nucleus, including a point source with a hard spectrum that is coincident…

Astrophysics · Physics 2009-11-07 D. L. Clements , J. C. McDowell , S. Shaked , A. C. Baker , K. Borne , L. Colina , S. Lamb , C. Mundell

We investigate the nature and classification of PMNJ1603-4904, a bright radio source close to the Galactic plane, which is associated with one of the brightest hard-spectrum gamma-ray sources detected by Fermi/LAT. It has previously been…

We present optical spectra and high-resolution multi-wavelength radio observations of the compact steep-spectrum radio source MRC B1221-423 (z=0.1706). MRC B1221-423 is a very young (~10^5 yr), powerful radio source which is undergoing a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Helen M. Johnston , Jess W. Broderick , Garret Cotter , Raffaella Morganti , Richard W. Hunstead

We investigate the nature of low-luminosity radio-loud active galactic nuclei (RLAGN) selected from the LOFAR Two-metre Sky Survey (LoTSS) first data release (DR1). Using optical, mid-infrared, and radio data, we have conservatively…

Astrophysics of Galaxies · Physics 2024-03-01 J. Chilufya , M. J. Hardcastle , J. C. S. Pierce , J. H. Croston , B. Mingo , X. Zheng , R. D. Baldi , H. J. A. Röttgering

According to a generally accepted paradigm, small intrinsic sizes of Compact Steep Spectrum (CSS) radio sources are a direct consequence of their youth, but in later stages of their evolution they are believed to become large-scale sources.…

Astrophysics · Physics 2009-11-13 Andrzej Marecki , Magdalena Kunert-Bajraszewska , Ralph E. Spencer

We present multi-frequency and high-resolution studies of a sample of 24 radio transients sources discovered by comparing the NRAO VLA Sky Survey (NVSS) and Very Large Array Sky Survey (VLASS) surveys. All of them are characterized by a…

Astrophysics of Galaxies · Physics 2024-12-11 M. Kunert-Bajraszewska , A. Krauze , A. E. Kimball , L. Stawarz , P. Kharb , D. Stern , K. Mooley , K. Nyland , D. Koziel-Wierzbowska

We present very-long-baseline interferometry (VLBI) observations of a continuum radio source potentially associated with the fast radio burst source FRB 20190520B. Using the European VLBI network (EVN), we find the source to be compact on…

Less than half of the SNRs within 5 kpc have identified central sources, and only three are identified as the remnants of Type Ia SNe. Here, we report a systematic effort to search for compact central sources in the remaining 23 SNRs of…

We present intermediate resolution, wide wavelength coverage spectra for a complete sample of 14 compact radio sources taken with the aim of investigating the impact of the nuclear activity on the circumnuclear (ISM) in the early stages of…

Astrophysics · Physics 2009-11-13 J. Holt , C. N. Tadhunter , R. Morganti

We analyze 18 sources that were found to show interesting properties of periodicity, very soft spectra and/or large long-term variability in X-rays in our project of classification of sources from the 2XMMi-DR3 catalog but were poorly…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Dacheng Lin , Natalie A. Webb , Didier Barret

We have used the Very Large Array to search for compact milliarcsecond-size radio sources near methanol masers in high-mass star-forming regions. Such sources are required for Very Long Baseline Interferometry phase-referencing…

Astrophysics · Physics 2009-11-11 Y. Xu , M. J. Reid , K. M. Menten , X. W. Zheng

In this article I will briely review the current status of radio observations of nearby supernovae and their remnants. This review will initially address observations of the radio light curves of nearby core-collapse supernovae, followed by…

Astrophysics · Physics 2007-05-23 R. J. Beswick

We present first results from electronic Multi-Element Remotely Linked Interferometer Network (e-MERLIN) and electronic European VLBI Network (e-EVN) observations of a small sample of ultra-steep spectrum radio sources, defined as those…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-14 Megan K. Argo , Zsolt Paragi , Huub Röttgering , Hans-Rainer Klöckner , George Miley , Mehreen Mahmud

We have carried out a high-precision astrometric analysis of two very-long-baseline-interferometry (VLBI) epochs of observation of the 13 extragalactic radio sources in the complete S5 polar cap sample. The VLBI epochs span a time baseline…

Astrophysics of Galaxies · Physics 2016-11-30 I. Marti-Vidal , F. J. Abellan , J. M. Marcaide , J. C. Guirado , M. A. Perez-Torres , E. Ros

We present a new sample of Compact Steep Spectrum (CSS) sources with radio luminosity below 10^26 W/Hz at 1.4 GHz called the low luminosity compact (LLC) objects. The sources have been selected from FIRST survey and observed with MERLIN at…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 M. Kunert-Bajraszewska , M. P. Gawronski , A. Labiano , A. Siemiginowska