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Faraday tomography of broadband radio polarization surveys enables us to study magnetic fields and their interaction with the interstellar medium (ISM). Such surveys include the Global Magneto-Ionic Medium Survey (GMIMS), which covers the…

Faraday tomography allows us to map diffuse polarized synchrotron emission from our Galaxy and use it to interpret the magnetic field in the interstellar medium (ISM). We have applied Faraday tomography to 60 observations from the LOFAR…

Faraday rotation occurs along every line of sight in the Galaxy; Rotation Measure (RM) synthesis allows a three-dimensional representation of the interstellar magnetic field. This study uses data from the Global Magneto-Ionic Medium Survey,…

Observations of synchrotron emission at low radio frequencies reveal a labyrinth of polarised Galactic structures. However, the explanation for the wealth of structures remains uncertain due to the complex interactions between the…

We present a broadband polarization analysis of 36 discrete polarized radio sources over a very broad, densely-sampled frequency band. Our sample was selected on the basis of polarization behaviour apparent in narrowband archival data at…

高能天体物理现象 · 物理学 2016-07-06 C. S. Anderson , B. M. Gaensler , I. J. Feain

Faraday rotation of polarised background sources is a unique probe of astrophysical magnetic fields in a diverse range of foreground objects. However, to understand the properties of the polarised sources themselves and of depolarising…

The new generation of low-frequency radio telescopes, such as the Low Frequency Array (LOFAR: a Square Kilometre Array-low pathfinder), provides advancements in our capability of probing Galactic magnetism through low-frequency polarimetry.…

We develop a new method of extracting simultaneous measurements of weak lensing shear and a local rotation of the plane of polarization using observations of resolved radio sources. We show that the direction of polarization is…

宇宙学与河外天体物理 · 物理学 2018-09-28 Lee Whittaker , Richard A. Battye , Michael L. Brown

Faraday tomography of radio polarimetric data below 200 MHz from LOFAR are providing us with a new perspective on the diffuse and magnetized interstellar medium (ISM). Of particular interest is the discovery of Faraday-rotated synchrotron…

星系天体物理 · 物理学 2022-07-13 A. Bracco , E. Ntormousi , V. Jelić , M. Padovani , B. Šiljeg , A. Erceg , L. Turić , L. Ceraj , I. Šnidarić

Aims. An efficient means of locating calibrator sources for International LOFAR is developed and used to determine the average density of usable calibrator sources on the sky for subarcsecond observations at 140 MHz. Methods. We used the…

Understanding origin and evolution of cosmological magnetic fields requires knowledge of magnetic fields in different extragalactic environments. In this context, a powerful tool is the statistical analysis of the Faraday effect on the…

The LOFAR Two-metre Sky Survey (LoTSS) is an ongoing sensitive, high-resolution 120-168MHz survey of the entire northern sky for which observations are now 20% complete. We present our first full-quality public data release. For this data…

星系天体物理 · 物理学 2018-11-21 T. W. Shimwell , C. Tasse , M. J. Hardcastle , A. P. Mechev , W. L. Williams , P. N. Best , H. J. A. Röttgering , J. R. Callingham , T. J. Dijkema , F. de Gasperin , D. N. Hoang , B. Hugo , M. Mirmont , J. B. R. Oonk , I. Prandoni , D. Rafferty , J. Sabater , O. Smirnov , R. J. van Weeren , G. J. White , M. Atemkeng , L. Bester , E. Bonnassieux , M. Brüggen , G. Brunetti , K. T. Chyży , R. Cochrane , J. E. Conway , J. H. Croston , A. Danezi , K. Duncan , M. Haverkorn , G. H. Heald , M. Iacobelli , H. T. Intema , N. Jackson , M. Jamrozy , M. J. Jarvis , R. Lakhoo , M. Mevius , G. K. Miley , L. Morabito , R. Morganti , D. Nisbet , E. Orrú , S. Perkins , R. F. Pizzo , C. Schrijvers , D. J. B. Smith , R. Vermeulen , M. W. Wise , L. Alegre , D. J. Bacon , I. M. van Bemmel , R. J. Beswick , A. Bonafede , A. Botteon , S. Bourke , M. Brienza , G. Calistro Rivera , R. Cassano , A. O. Clarke , C. J. Conselice , R. J. Dettmar , A. Drabent , C. Dumba , K. L. Emig , T. A. Enßlin , C. Ferrari , M. A. Garrett , R. T. Génova-Santos , A. Goyal , G. Gürkan , C. Hale , J. J. Harwood , V. Heesen , M. Hoeft , C. Horellou , C. Jackson , G. Kokotanekov , R. Kondapally , M. Kunert-Bajraszewska , V. Mahatma , E. K. Mahony , S. Mandal , J. P. McKean , A. Merloni , B. Mingo , A. Miskolczi , S. Mooney , B. Nikiel-Wroczyński , S. P. O'Sullivan , J. Quinn , W. Reich , C. Roskowiński , A. Rowlinson , F. Savini , A. Saxena , D. J. Schwarz , A. Shulevski , S. S. Sridhar , H. R. Stacey , S. Urquhart , M. H. D. van der Wiel , E. Varenius , B. Webster , A. Wilber

We investigate the potential of the Square Kilometre Array (SKA) for measuring the magnetic fields in clusters of galaxies via Faraday rotation of background polarised sources. [...] We find that about 10 per cent of the sky is covered by a…

宇宙学与河外天体物理 · 物理学 2015-05-13 Martin Krause , Paul Alexander , Rosie Bolton , Joern Geisbuesch , David A. Green , Julia Riley

The Polarisation Sky Survey of the Universe's Magnetism (POSSUM) will conduct a sensitive $\sim$1 GHz radio polarization survey covering 20 000 square degrees of the Southern sky with the Australian Square Kilometre Array Pathfinder…

Synchrotron emission, its polarization and its Faraday rotation at radio frequencies of 0.2-10 GHz are powerful tools to study the strength and structure of cosmic magnetic fields. The observational results are reviewed for spiral, barred…

宇宙学与河外天体物理 · 物理学 2015-05-27 Rainer Beck

Giant radio galaxies (GRGs) are physically large radio sources that extend well beyond their host galaxy environment. Their polarization properties are affected by the poorly constrained magnetic field that permeates the intergalactic…

We investigate whether the method of wavelet-based Faraday rotation measure (RM) Synthesis can help us to identify structures of regular and turbulent magnetic fields in extended magnetized objects, such as galaxies and galaxy clusters.…

天体物理仪器与方法 · 物理学 2015-06-04 R. Beck , P. Frick , R. Stepanov , D. Sokoloff

We present the first spectropolarimetric radio observations that apply Rotation Measure (RM) Synthesis to interferometric data from the Giant Metrewave Radio Telescope (GMRT) at 610 MHz. Spectropolarimetry requires measurement of a large…

天体物理仪器与方法 · 物理学 2013-09-19 J. S. Farnes , D. A. Green , N. G. Kantharia

The aim of this study is to probe the sub-mJy polarized source population with LOFAR. We present the method used to stack LOFAR polarization datasets, the resulting catalog of polarized sources, and the derived polarized source counts. The…

The low-frequency linearly-polarised radio source population is largely unexplored. However, a renaissance in low-frequency polarimetry has been enabled by pathfinder and precursor instruments for the Square Kilometre Array. In this second…