LOFAR tied-array imaging of Type III solar radio bursts
Journal article, 2014

Context. The Sun is an active source of radio emission which is often associated with energetic phenomena such as solar flares and coronal mass ejections (CMEs). At low radio frequencies (< 100 MHz), the Sun has not been imaged extensively because of the instrumental limitations of previous radio telescopes. Aims. Here, the combined high spatial, spectral, and temporal resolution of the LOw Frequency ARray (LOFAR) was used to study solar Type III radio bursts at 30-90 MHz and their association with CMEs. Methods. The Sun was imaged with 126 simultaneous tied-array beams within <= 5 R-circle dot of the solar centre. This method offers benefits over standard interferometric imaging since each beam produces high temporal (similar to 83 ms) and spectral resolution (12.5 kHz) dynamic spectra at an array of spatial locations centred on the Sun. LOFAR's standard interferometric output is currently limited to one image per second. Results. Over a period of 30 min, multiple Type III radio bursts were observed, a number of which were found to be located at high altitudes (similar to 4 R-circle dot from the solar center at 30 MHz) and to have non-radial trajectories. These bursts occurred at altitudes in excess of values predicted by 1D radial electron density models. The non-radial high altitude Type III bursts were found to be associated with the expanding flank of a CME. Conclusions. The CME may have compressed neighbouring streamer plasma producing larger electron densities at high altitudes, while the non-radial burst trajectories can be explained by the deflection of radial magnetic fields as the CME expanded in the low corona.

spacecraft

shock

density

radioheliograph

corona

acceleration

electrons

waves

plasma emission

Author

D. E. Morosan

Trinity College Dublin

P. T. Gallagher

Trinity College Dublin

P. Zucca

Trinity College Dublin

R. A. Fallows

Netherlands Institute for Radio Astronomy (ASTRON)

E. P. Carley

Trinity College Dublin

G. Mann

Leibniz Institute for Astrophysics Potsdam

M. M. Bisi

STFC Rutherford Appleton Laboratory

A. Kerdraon

Observatoire de Paris-Meudon

A. A. Konovalenko

National Academy of Sciences in Ukraine

A. L. MacKinnon

University of Glasgow

H. O. Rucker

Osterreichische Akademie Der Wissenschaften

B. Thide

The Swedish Institute of Space Physics

J. Magdalenic

Royal Observatory of Belgium

C. Vocks

Leibniz Institute for Astrophysics Potsdam

H. Reid

University of Glasgow

J. Anderson

Leibniz Institute for Astrophysics Potsdam

A. Asgekar

Shell Technology Center

Netherlands Institute for Radio Astronomy (ASTRON)

I.M. Avruch

University of Groningen

Netherlands Institute for Space Research (SRON)

M. J. Bentum

Netherlands Institute for Radio Astronomy (ASTRON)

G. Bernardi

Harvard-Smithsonian Center for Astrophysics

P. Best

University of Edinburgh

A. Bonafede

University of Hamburg

I. Bregman

Netherlands Institute for Radio Astronomy (ASTRON)

F. Breitling

Leibniz Institute for Astrophysics Potsdam

J. Broderick

University of Southampton

M. Brueggen

University of Hamburg

H. R. Butcher

Australian National University

B. Ciardi

Max Planck Society

John Conway

Chalmers, Earth and Space Sciences, Onsala Space Observatory

F. De Gasperin

University of Hamburg

E. de Geus

Netherlands Institute for Radio Astronomy (ASTRON)

A. Deller

Netherlands Institute for Radio Astronomy (ASTRON)

S. Duscha

Netherlands Institute for Radio Astronomy (ASTRON)

J. Eislöffel

D. Engels

University of Hamburg

H. Falcke

Netherlands Institute for Radio Astronomy (ASTRON)

Radboud University

C. Ferrari

Université Nice Sophia Antipolis (UNS)

W. Frieswijk

Netherlands Institute for Radio Astronomy (ASTRON)

M. A. Garrett

Netherlands Institute for Radio Astronomy (ASTRON)

Leiden University

J. Griessmeier

University of Orléans

A. W. Gunst

Netherlands Institute for Radio Astronomy (ASTRON)

T. E. Hassall

University of Southampton

University of Manchester

J. W. T. Hessels

Anton Pannekoek Institute for Astronomy

Netherlands Institute for Radio Astronomy (ASTRON)

M. Hoeft

J.R. Hörandel

Radboud University

A. Horneffer

Max Planck Society

M. Iacobelli

Leiden University

E. Juette

Ruhr-Universität Bochum

A. Karastergiou

University of Oxford

V. I. Kondratiev

Netherlands Institute for Radio Astronomy (ASTRON)

Russian Academy of Sciences

M. Kramer

University of Manchester

Max Planck Society

M. Kuniyoshi

Max Planck Society

G. Kuper

Netherlands Institute for Radio Astronomy (ASTRON)

P. Maat

Netherlands Institute for Radio Astronomy (ASTRON)

S. Markoff

Anton Pannekoek Institute for Astronomy

J. P. McKean

University of Groningen

Netherlands Institute for Radio Astronomy (ASTRON)

D. D. Mulcahy

Max Planck Society

H. Munk

Netherlands Institute for Radio Astronomy (ASTRON)

A. Nelles

Radboud University

M. J. Norden

Netherlands Institute for Radio Astronomy (ASTRON)

E. Orru

Netherlands Institute for Radio Astronomy (ASTRON)

H. Paas

University of Groningen

M. Pandey-Pommier

Lyon Observatory

V. N. Pandey

Netherlands Institute for Radio Astronomy (ASTRON)

G. Pietka

University of Oxford

R. Pizzo

Netherlands Institute for Radio Astronomy (ASTRON)

A. G. Polatidis

Netherlands Institute for Radio Astronomy (ASTRON)

W. Reich

Max Planck Society

H. Rottgering

Leiden University

A. M. M. Scaife

University of Southampton

D. Schwarz

Bielefeld University

M. Serylak

University of Oxford

O. Smirnov

Rhodes University

B. W. Stappers

University of Manchester

A. Stewart

University of Oxford

M. Tagger

University of Orléans

Y. Tang

Netherlands Institute for Radio Astronomy (ASTRON)

C. Tasse

Observatoire de Paris-Meudon

S. Thoudam

Radboud University

C. Toribio

Netherlands Institute for Radio Astronomy (ASTRON)

R. Vermeulen

Netherlands Institute for Radio Astronomy (ASTRON)

R. J. van Weeren

Harvard-Smithsonian Center for Astrophysics

O. Wucknitz

University of Bonn

Max Planck Society

S. Yatawatta

Netherlands Institute for Radio Astronomy (ASTRON)

P. Zarka

Observatoire de Paris-Meudon

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 568 articl no. A67- A67

Subject Categories

Astronomy, Astrophysics and Cosmology

DOI

10.1051/0004-6361/201423936

More information

Latest update

7/9/2021 9