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Related papers: Tackling the Unique Challenges of Low-frequency So…

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Coronal magnetic fields are well known to be one of the crucial parameters defining coronal physics and space weather. However, measuring the global coronal magnetic fields remains challenging. The polarization properties of coronal radio…

Solar and Stellar Astrophysics · Physics 2022-07-01 Devojyoti Kansabanik , Divya Oberoi , Surajit Mondal

Magnetic field couples the solar interior to the solar atmosphere, known as the corona. The coronal magnetic field is one of the crucial parameters which determines the coronal structures and regulates the space weather phenomena like…

Solar and Stellar Astrophysics · Physics 2022-07-26 Devojyoti Kansabanik , Divya Oberoi , Surajit Mondal

Imaging the low-frequency radio Sun is an intrinsically challenging problem. Meter-wavelength solar emission spans angular scales from a few arcminutes to a few degrees. These emissions show temporal and spectral variability on a sub-second…

Solar and Stellar Astrophysics · Physics 2022-09-22 Devojyoti Kansabanik

Solar radio emission, especially at metre-wavelengths, is well known to vary over small spectral ($\lesssim$100\,kHz) and temporal ($<1$\,s) spans. It is comparatively recently, with the advent of a new generation of instruments, that it…

Instrumentation and Methods for Astrophysics · Physics 2019-05-01 Surajit Mondal , Atul Mohan , Divya Oberoi , John S. Morgan , Leonid Benkevitch , Colin J. Lonsdale , Meagan Crowley , Iver H. Cairns

We present spectropolarimetric imaging observations of the solar corona at low frequencies (80 - 240 MHz) using the Murchison Widefield Array (MWA). These images are the first of their kind, and we introduce an algorithm to mitigate an…

Solar and Stellar Astrophysics · Physics 2019-09-04 Patrick I. McCauley , Iver H. Cairns , Stephen M. White , Surajit Mondal , Emil Lenc , John Morgan , Divya Oberoi

Low-frequency radio observations have been expected to serve as a powerful tool for Space Weather (SW) observations for decades. Radio observations are sensitive to a wide range of SW-related observations ranging from emissions from coronal…

Solar and Stellar Astrophysics · Physics 2023-02-01 Devojyoti Kansabanik , Surajit Mondal , Divya Oberoi , Puja Majee

We present techniques developed to calibrate and correct Murchison Widefield Array (MWA) low frequency (72-300 MHz) radio observations for polarimetry. The extremely wide field-of-view, excellent instantaneous (u, v)-coverage and…

Bodies such as planets, moons, and asteroids in our solar system are the brightest objects in the low-frequency radio astronomy at $\lesssim$ 10 GHz. The low-frequency radio emissions from our solar system bodies exhibit various observed…

Earth and Planetary Astrophysics · Physics 2023-03-15 Tomoki Kimura , Yuka Fujii , Hajime Kita , Fuminori Tsuchiya , Hideo Sagawa , the SKA-Japan Planetary Science Team

Understanding many physical processes in the solar atmosphere requires determination of the magnetic field in each atmospheric layer. However, direct measurements of the magnetic field in the Sun's corona are difficult to obtain. Using…

The Sun has remained a difficult source to image for radio telescopes, especially at the low radio frequencies. Its morphologically complex emission features span a large range of angular scales, emission mechanisms involved and brightness…

Low frequency imaging radio arrays such as MWA, LWA and LOFAR have been recently commissioned, and significantly more advanced and flexible arrays are planned for the near term. These powerful instruments offer new opportunities for direct…

Instrumentation and Methods for Astrophysics · Physics 2018-02-07 C. Lonsdale , L. Benkevitch , I. Cairns , M. Crowley , P. Erickson , M. Knapp , K. Kozarev , F. Lind , P. McCauley , J. Morgan , D. Oberoi

Weak gravitational lensing measurements are traditionally made at optical wavelengths where many highly resolved galaxy images are readily available. However, the Square Kilometre Array (SKA) holds great promise for this type of measurement…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-19 Prina Patel , Ian Harrison , Sphesihle Makhathini , Filipe Abdalla , David Bacon , Michael L. Brown , Ian Heywood , Matt Jarvis , Oleg Smirnov

The future new-generation radio telescope SKA (Square Kilometre Array) and its precursors will provide a rapidly growing number of polarized radio sources. Hundred and thousands polarized background sources can be measured towards nearby…

Astrophysics · Physics 2007-12-03 T. G. Arshakian , R. Stepanov , R. Beck , P. Frick , M. Krause

Low-frequency (80-240 MHz) radio observations of the solar corona are presented using the Murchison Widefield Array (MWA), and several discoveries are reported. The corona is reviewed, followed by chapters on Type III bursts and…

Solar and Stellar Astrophysics · Physics 2019-12-05 Patrick I. McCauley

We present the first spectroscopic images of solar radio transients from the prototype for the Murchison Widefield Array (MWA), observed on 2010 March 27. Our observations span the instantaneous frequency band 170.9-201.6 MHz. Though our…

Solar radio observations provide a unique diagnostic of the outer solar atmosphere. However, the inhomogeneous turbulent corona strongly affects the propagation of the emitted radio waves, so decoupling the intrinsic properties of the…

Solar and Stellar Astrophysics · Physics 2018-02-22 E. P. Kontar , S. Yu , A. A. Kuznetsov , A. G. Emslie , B. Alcock , N. L. S. Jeffrey , V. N. Melnik , N. H. Bian , P. Subramanian

The quiet solar corona emits meter-wave thermal bremsstrahlung. Coronal radio emission can only propagate above that radius, $R_\omega$, where the local plasma frequency eqals the observing frequency. The radio interferometer LOw Frequency…

Solar and Stellar Astrophysics · Physics 2018-06-13 C. Vocks , G. Mann , F. Breitling , M. M. Bisi , B. Dabrowski , R. Fallows , P. T. Gallagher , A. Krankowski , J. Magdalenic , C. Marque , D. Morosan , H. Rucker

Polarimetric radio observations of the Sun can provide rich information about emission mechanisms and the propagation medium. For the past five decades, solar polarimetric studies at low radio frequencies have almost always assumed the…

Solar and Stellar Astrophysics · Physics 2025-08-05 Soham Dey , Devojyoti Kansabanik , Divya Oberoi , Surajit Mondal

The critical need to study the magnetic field in the solar corona is highlighted by recent observational facilities, such as DKIST and Aditya-L1. A powerful tool for probing the magnetism of the solar corona is forward modeling of the…

The Square Kilometre Array (SKA) will be the largest radio telescope ever built, aiming to provide collecting area larger than 1 km$^2$. The SKA will have two independent instruments, SKA-LOW comprising of dipoles organized as aperture…

Solar and Stellar Astrophysics · Physics 2019-02-13 A. Nindos , E. P. Kontar , D. Oberoi
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