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At very low frequencies, the new pan-European radio telescope LOFAR is opening the last unexplored window of the electromagnetic spectrum for astrophysical studies. The revolutionary APERTIF phased arrays that are about to be installed on…

As radio telescopes increase in sensitivity and flexibility, so do their complexity and data-rates. For this reason automated system health management approaches are becoming increasingly critical to ensure nominal telescope operations. We…

Instrumentation and Methods for Astrophysics · Physics 2023-12-13 Michael Mesarcik , Albert-Jan Boonstra , Marco Iacobelli , Elena Ranguelova , Cees de Laat , Rob van Nieuwpoort

A cross-correlation of the SDSS DR7 with the FIRST radio survey makes it possible to conduct a joined multiwavelength statistical study of radio-optical galaxy properties on a very large number of sources. Our goal is to improve the study…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 M. Vitale , J. Zuther , M. Garcia-Marin , A. Eckart , M. Bremer , M. Valencia-S. , A. Zensus

This paper describes the automated optical APM identification of radio sources from the Jodrell Bank - VLA Astrometric Survey (JVAS), as used for the search for distant radio-loud quasars. The sample has been used to investigate possible…

Astrophysics · Physics 2009-11-07 Ignas Snellen , Richard McMahon , Isobel Hook , Ian Browne

Modern radio interferometers deliver large volumes of data containing high-sensitivity sky maps over wide fields-of-view. These large area observations can contain various and superposed structures such as point sources, extended objects,…

Instrumentation and Methods for Astrophysics · Physics 2025-12-05 Richard Fuchs , Jakob Knollmüller , Jakob Roth , Vincent Eberle , Philipp Frank , Torsten A. Enßlin , Lukas Heinrich

Aims: This paper discusses the spectral occupancy for performing radio astronomy with the Low-Frequency Array (LOFAR), with a focus on imaging observations. Methods: We have analysed the radio-frequency interference (RFI) situation in two…

We present the first sub-mJy ($\approx0.7$ mJy beam$^{-1}$) survey to be completed below 100 MHz, which is over an order of magnitude deeper than previously achieved for widefield imaging of any field at these low frequencies. The high…

It has long been known that luminous, ultra-steep spectrum radio sources are preferentially associated with massive galaxies at high redshifts. Here we describe a pilot project directed at such objects, to demonstrate the feasibility and…

Astrophysics of Galaxies · Physics 2023-08-02 C. M. Cordun , R. Timmerman , G. K. Miley , R. J. van Weeren , F. Sweijen , L. K. Morabito , H. J. A. Röttgering

A significant fraction of galaxy clusters exhibits cluster wide radio halos. We give a simple prediction of the local and higher redshift radio halo luminosity function (RHLF) on the basis of (i) an observed and a theoretical X-ray cluster…

Astrophysics · Physics 2009-11-07 Torsten A. Ensslin , Huub Roettgering

The Lockman Hole Project is a wide international collaboration aimed at exploiting the multi-band extensive and deep information available for the Lockman Hole region, with the aim of better characterizing the physical and evolutionary…

Astrophysics of Galaxies · Physics 2019-08-14 Elizabeth K. Mahony , Raffaella Morganti , Isabella Prandoni , Ilse van Bemmel

We present early results from Radio Galaxy Zoo, a web-based citizen science project for visual inspection and classification of images from all-sky radio surveys. The goals of the project are to classify individual radio sources…

Astrophysics of Galaxies · Physics 2016-03-09 Kyle W. Willett

We present a classification-based approach to identify quasi-stellar radio sources (quasars) in the Sloan Digital Sky Survey and evaluate its performance on a manually labeled training set. While reasonable results can already be obtained…

Instrumentation and Methods for Astrophysics · Physics 2016-11-18 Fabian Gieseke , Kai Lars Polsterer , Andreas Thom , Peter-Christian Zinn , Dominik Bomanns , Ralf-Jürgen Dettmar , Oliver Kramer , Jan Vahrenhold

We present the results of an all-sky radio survey between 5 and 9 GHz of the fields surrounding all unassociated gamma-ray objects listed in the Fermi Large Area Telescope Second Source Catalog (2FGL). The goal of these observations is to…

High Energy Astrophysical Phenomena · Physics 2015-03-12 Frank K. Schinzel , Leonid Petrov , Gregory B. Taylor , Elizabeth K. Mahony , Philip G. Edwards , Yuri Y. Kovalev

Large surveys using modern telescopes are producing images that are increasing exponentially in size and quality. Identifying objects in the generated images by visual recognition is time-consuming and labor-intensive, while classifying the…

Instrumentation and Methods for Astrophysics · Physics 2021-09-28 Baoqiang Lao , Tao An , Ailing Wang , Zhijun Xu , Shaoguang Guo , Weijia Lv , Xiaocong Wu , Yingkang Zhang

Next-generation radio surveys are expected to detect tens of millions of active galactic nuclei (AGN) with a median redshift of z > 1. Beyond targeted surveys, the vast majority of these objects will not have spectroscopic redshifts, whilst…

Astrophysics of Galaxies · Physics 2020-11-03 Ross J. Turner , Guillaume Drouart , Nick Seymour , Stanislav S. Shabala

The existence of double-double radio galaxies (DDRGs) is evidence for recurrent jet activity in AGN, as expected from standard accretion models. A detailed study of these rare sources provides new perspectives for investigating the AGN duty…

We have conducted an optical/near-infrared study of the environments of radio-loud quasars (RLQs) at redshifts z=0.6-2. In this paper we discuss the sample selection and observations for the z=1-2 subsample and the reduction and cataloguing…

Astrophysics · Physics 2009-10-30 Patrick B. Hall , Richard F. Green , Martin Cohen

We investigate the clustering properties of ~1550 broad-line active galactic nuclei (AGNs) at <z>=0.25 detected in the ROSAT All-Sky Survey (RASS) through their measured cross-correlation function with ~46,000 Luminous Red Galaxies (LRGs)…

Cosmology and Nongalactic Astrophysics · Physics 2010-03-26 Mirko Krumpe , Takamitsu Miyaji , Alison L. Coil

The Combined EIS-NVSS Survey Of Radio Sources (CENSORS) has been produced with the primary goal of investigating the cosmological evolution of the radio luminosity function. This 1.4GHz sample, complete to the 7.2 mJy level, contains 150…

Astrophysics · Physics 2017-08-23 M. H. Brookes , P. N. Best

In order to determine the incidence of black hole accretion-driven nuclear activity in nearby galaxies, as manifested by their radio emission, we have carried out a high-resolution Multi-Element Radio-Linked Interferometer Network (MERLIN)…

Astrophysics · Physics 2009-11-11 M. E. Filho , P. D. Barthel , L. C. Ho
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