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We have assembled an 8.4 GHz survey of bright, flat-spectrum (alpha > -0.5) radio sources with nearly uniform extragalactic (|b|>10 deg) coverage for sources brighter than S_{4.8 GHz} = 65 mJy. The catalog is assembled from existing…

We present searches for molecular gas (CO, OH, CS, and Ammonia) in six GHz Peaked Spectrum (GPS) radio sources. We do not detect gas in any source and place upper limits on the mass of molecular gas which are generally in the range 1E9 to a…

Astrophysics · Physics 2009-11-10 C. P. O'Dea , J. Gallimore , C. Stanghellini , S. A. Baum , J. M. Jackson

It is currently accepted that intrinsically compact and bright radio sources characterized by a convex spectrum peaking at frequencies ranging from 100 MHz to a few GHz are young objects. Following the evolutionary models, these objects…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-02 M. Orienti , D. Dallacasa

Aims: The knowledge of the properties of the youngest radio sources is very important in order to trace the earliest phase of the evolution of the radio emission. RXJ1459+3337, with its high turnover frequency (~25 GHz) provides a unique…

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

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

We present an analysis of the spectral properties of the extragalactic radio sources in the nearly-complete VSA sample at 33GHz. Data from different surveys are used to study source spectra between 1.4 and 33GHz. We find that, in general,…

A detailed understanding of how the activity of a galactic nucleus regulates the growth of its host is still missing. To understand the activity and the types of accretion of supermassive black holes in different hosts, it is essential to…

We present the results of HI absorption measurements towards a sample of nearby Compact Steep-Spectrum (CSS) and Giga-Hertz Peaked Spectrum (GPS) radio sources, the CORALZ sample, using the Giant Metrewave Radio Telescope (GMRT). We…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Yogesh Chandola , S. K. Sirothia , D. J. Saikia

As part of the GLOSTAR survey we have used the VLA in its B-configuration to observe the part of the Galactic plane between longitudes of 28d and 36d and latitudes from -1d to +1d at the C-band (4--8 GHz). To reduce the contamination of…

Aims. With the recent preliminary release of the LOFAR LBA Sky Survey (LoLSS), the first wide-area, ultra-low frequency observations from LOFAR were published. Our aim is to combine this data set with other surveys at higher frequencies to…

Instrumentation and Methods for Astrophysics · Physics 2023-06-22 Lukas Böhme , Dominik J. Schwarz , Francesco de Gasperin , Huub J. A. Röttgering , Wendy L. Williams

While unobscured and radio-quiet active galactic nuclei are regularly being found at redshifts $z > 6$, their obscured and radio-loud counterparts remain elusive. We build upon our successful pilot study, presenting a new sample of…

Many low-luminosity active galactic nuclei (AGNs) contain a compact radio core which can be observed with high angular resolution using very long baseline interferometry (VLBI). Combining arcsec-scale structural information with…

Astrophysics of Galaxies · Physics 2020-04-06 Máté Krezinger , Sándor Frey , Zsolt Paragi , Roger Deane

We are conducting a multi-wavelength (radio, optical, and X-ray) observational campaign to classify, morphologically and physically, a sample of 55 flat-spectrum radio sources dominated by structure on kpc-scales. This sample contains 22…

We present optical spectroscopy of 62 objects selected from several samples of ultra steep spectrum (USS) radio sources. 46 of these are from our primary catalog, consisting of 669 sources with radio spectral indices alpha < -1.30 (S_nu ~…

GPS and CSS radio sources are the objects of choice to investigate the evolution of young radio-loud AGN. Previous investigations, mainly based on number counts and source size distributions, indicate that GPS/CSS sources decrease…

Astrophysics · Physics 2009-11-07 I. A. G. Snellen , K. -H. Mack , R. T. Schilizzi , W. Tschager

We present a low-frequency imaging study of an extended sample of X-shaped radio sources using the Giant Metrewave radio telescope (GMRT) at two frequencies (610 and 240 MHz). The sources were drawn from a Very Large Array FIRST-selected…

Astrophysics of Galaxies · Physics 2019-05-08 Dharam V. Lal , Biny Sebastian , C. C. Cheung , A. Pramesh Rao

Based on the FIRST and SDSS catalogues a flux density limited sample of weak Compact Steep Spectrum (CSS) sources with radio luminosity below 10^26 [W/Hz] at 1.4 GHz has been constructed. Our previous multifrequency observations of CSS…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-11 Magdalena Kunert-Bajraszewska , Peter Thomasson

We present the 100 strongest 1.4 GHz point sources from a new mosaic image in the direction of the Large Magellanic Cloud (LMC). The observations making up the mosaic were made over a ten year period and were combined with Parkes single…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 J. L. Payne , L. A. Tauber , M. D. Filipovic , E. J. Crawford , A. Y. De Horta

We use the Very Long Baseline Array to conduct high precision astrometry of a sample of 33 compact, flat spectrum, variable radio sources in the direction of the Galactic plane (Becker et al. 2010). Although Becker et al. (2010) ruled out a…

High Energy Astrophysical Phenomena · Physics 2022-10-12 P. Atri , J. C. A. Miller-Jones , A. Bahramian , R. M. Plotkin , T. J. Maccarone , B. Marcote , C. O. Heinke , G. R. Sivakoff , A. Ginsburg , L. Chomiuk

We have performed deep imaging in the IR J- and K-bands for three sub-samples of radio sources extracted from the Westerbork Northern Sky Survey, a large low-frequency radio survey containing Ultra Steep Spectrum (USS), Gigahertz Peaked…

Astrophysics · Physics 2009-10-31 D. Villani , S. di Serego Alighieri
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