English
Related papers

Related papers: First LOFAR results on galaxy clusters

200 papers

The LOw Frequency ARray (LOFAR) is a next-generation radio telescope which uses thousands of stationary dipoles to observe celestial phenomena. These dipoles are grouped in various 'stations' which are centred on the Netherlands with…

Solar and Stellar Astrophysics · Physics 2019-08-13 Richard A. Fallows , Ashish Asgekar , Mario M Bisi , Andrew R. Breen , Sander ter Veen

Radio astronomy is entering the era of large surveys. This paper describes the plans for wide surveys with the LOw Frequency ARray (LOFAR) and their synergy with large surveys at higher frequencies (in particular in the 1-2 GHz band) that…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-15 R. Morganti , H. Rottgering , I. Snellen , G. Miley , P. Barthel , P. Best , M. Bruggen , G. Brunetti , K. Chyzy , J. Conway , M. Jarvis , M. Lehnert

LOFAR is a new form of radio telescope which can detect radio emission from air showers induced by very high-energy cosmic rays. It can also look for radio emission from particle cascades on the Moon induced by ultra high-energy cosmic rays…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 S. Thoudam , G. v. Aar , M. v. d. Akker , L. Bähren , A. Corstanje , H. Falcke , J. R. Hörandel , A. Horneffer , C. James , M. Mevius , O. Scholten , K. Singh , S. ter Veen

Radio galaxies are linearly polarized -- an important property that allows us to infer the properties of the magnetic field of the source and its environment. However at low frequencies, Faraday rotation substantially depolarizes the…

LOFAR, the Low Frequency Array, is a large radio telescope consisting of approximately 100 soccer-field sized antenna stations spread over a region of 400 km in diameter. It will operate at frequencies from ~10 to 240 MHz, with a resolution…

Astrophysics · Physics 2009-11-10 H. J. A. Rottgering

$\textit{Context.}$ The magnetized Solar System planets are strong radio emitters and theoretical studies suggest that the radio emission from nearby exoplanets in close-in orbits could reach intensity levels $10^{3}-10^{7}$ times higher…

Earth and Planetary Astrophysics · Physics 2019-04-10 Jake D. Turner , Jean-Mathias Grießmeier , Philippe Zarka , Iaroslavna Vasylieva

LOFAR, the Low Frequency Array, is a large radio telescope consisting about 100 soccer field sized antenna stations spread over a region of 400 km in diameter. It will operate in the frequency range from ~10 to 240 MHz, with a resolution at…

The LOw Frequency ARray (LOFAR) has successfully measured cosmic rays for over a decade now. With its dense core of antenna fields in the Netherlands, it is an ideal tool for studying the radio emission from extensive air showers in the…

This short paper reviews some of the results obtained from ISO observations (ISOCAM and ISOPHOT) on galaxy clusters: Chap.1: "Intracluster dust": new evidence for the presence of dust outside galaxies. Chap.2:"Mid-Infrared Emission of…

Astrophysics · Physics 2007-05-23 David Elbaz

LOFAR, the "low-frequency array", will be one of the first in a new generation of radio telescopes and Square Kilometer Array (SKA) pathfinders that are highly flexible in capability because they are largely software driven. LOFAR will not…

Instrumentation and Methods for Astrophysics · Physics 2009-03-10 J. W. T. Hessels , B. W. Stappers , J. van Leeuwen , LOFAR Transients Key Science Project

The central regions of galaxy clusters are permeated by magnetic fields and filled with relativistic electrons. When clusters merge, the magnetic fields are amplified and relativistic electrons are re-accelerated by turbulence in the intra…

We take the established relation between black hole mass, X-ray luminosity, and radio luminosity and show that intermediate mass black holes, such as those predicted to exist at the centers of globular clusters, will be easily identifiable…

Astrophysics · Physics 2009-11-10 Thomas J. Maccarone

We describe a new method for identifying and characterizing the thermodynamic state of large samples of evolved galaxy groups at high redshifts using high-resolution, low-frequency radio surveys, such as those that will be carried out with…

Astrophysics of Galaxies · Physics 2017-07-26 J. H. Croston , J. Ineson , M. J. Hardcastle , B. Mingo

Radio emission in the form of giant radio relics is observed at the periphery of galaxy clusters. This non-thermal emission is an important tracer for cosmic-ray electrons and intracluster magnetic fields. One striking observational feature…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-08 Denis Wittor , Matthias Hoeft , Franco Vazza , Marcus Brüggen , Paola. Domínguez-Fernández

The presence of magnetic fields in galaxy clusters has been well established in recent years, and their importance for the understanding of the physical processes at work in the Intra Cluster Medium has been recognized. Halo and relic…

Recent radio observations with Low-Frequency Array (LOFAR) discovered diffuse emission extending beyond the scale of classical radio halos. The presence of such mega halos indicates that the amplification of the magnetic field and…

High Energy Astrophysical Phenomena · Physics 2023-12-05 Kosuke Nishiwaki , Gianfranco Brunetti , Franco Vazza , Claudio Gheller

Results are presented of a new VLA-ROSAT study that probes the magnetic field strength and distribution over a sample of 16 ``normal'' low redshift (z < 0.1) galaxy clusters. The clusters span two orders of magnitude in X-ray luminosity,…

Astrophysics · Physics 2009-10-31 T. E. Clarke , P. P. Kronberg , H. Boehringer

The polarization properties of radio sources at very low frequencies (<200 MHz) have not been widely measured, but the new generation of low-frequency radio telescopes, including the Low Frequency Array (LOFAR: a Square Kilometre Array Low…

We examine the remnant phase of radio galaxies using three-dimensional hydrodynamical simulations of relativistic jets propagating through cluster environments. By switching the jets off once the lobes have reached a certain length we can…

High Energy Astrophysical Phenomena · Physics 2020-01-08 W. English , M. J. Hardcastle , M. G. H. Krause

Neutron stars that show X-ray and $\gamma$-ray pulsed emission must, somewhere in the magnetosphere, generate electron-positron pairs. Such pairs are also required for radio emission, but then why do a number of these sources appear radio…

High Energy Astrophysical Phenomena · Physics 2023-04-19 Inés Pastor-Marazuela , Samayra M. Straal , Joeri van Leeuwen , Vlad I. Kondratiev