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We present the first dedicated observations of Interplanetary Scintillation (IPS) with the Murchison Widefield Array (MWA). We have developed a synthesis imaging technique, tailored to the properties of modern "large-N" low-frequency radio…

Instrumentation and Methods for Astrophysics · Physics 2017-09-12 J . S. Morgan , J-P. Macquart , R. Ekers , R. Chhetri , M. Tokumaru , P. K. Manoharan , S. Tremblay , M. M. Bisi , B. V. Jackson

Around 10% of bright low-frequency radio sources observed with the Murchison Widefield Array (MWA) show strong Interplanetary Scintillation (IPS) on timescales of a few seconds, implying that almost all their low-frequency radio emission…

Astrophysics of Galaxies · Physics 2018-11-28 Elaine M. Sadler , Rajan Chhetri , John Morgan , Elizabeth K. Mahony , Thomas H. Jarrett , Steven Tingay

We describe the parameters of a low-frequency all-sky survey of compact radio sources using Interplanetary Scintillation (IPS), undertaken with the Murchison Widefield Array (MWA). While this survey gives important complementary information…

Astrophysics of Galaxies · Physics 2019-02-08 J. S. Morgan , J-P. Macquart , R. Chhetri , R. D. Ekers , S. J. Tingay , E. M. Sadler

We report the first astrophysical application of the technique of wide-field Interplanetary Scintillation (IPS) with the Murchison Widefield Array (MWA). This powerful technique allows us to identify and measure sub-arcsecond compact…

High Energy Astrophysical Phenomena · Physics 2018-01-10 R. Chhetri , J. Morgan , R. D. Ekers , J-P Macquart , E. M. Sadler , M. Giroletti , J. R. Callingham , S. J. Tingay

Observation of interplanetary scintillation (IPS) beyond Earth-orbit can be challenging due to the necessity to use low radio frequencies at which scintillation due to the ionosphere could confuse the interplanetary contribution. A recent…

Instrumentation and Methods for Astrophysics · Physics 2016-09-07 R. A. Fallows , M. M. Bisi , B. Forte , Th. Ulich , A. A. Konovalenko , G. Mann , C. Vocks

We have shown previously that the Murchison Widefield Array (MWA), can detect hundreds of Interplanetary Scintillation (IPS) sources simultaneously across a field of view $\sim30^\circ$ in extent. To test if we can use this capability to…

Solar and Stellar Astrophysics · Physics 2023-05-15 J. Morgan , P. I. McCauley , A. Waszewski , R. Ekers , R. Chhetri

We have conducted a comprehensive comparison of interplanetary scintillation (IPS) observations taken by the Murchison Widefield Array (MWA) with several heliospheric transient event catalogues, over a time period of 7 months during solar…

Solar and Stellar Astrophysics · Physics 2025-11-11 A. Waszewski , J. S. Morgan , M. C. M. Cheung , R. Ekers , E. Samara , S. Majumdar , R. Chhetri , N. D. R. Bhat , M. Johnston-Hollitt

Observations over the last two decades have shown that a significant fraction of all flat-spectrum, extragalactic radio sources exhibit flux density variations on timescales of a day or less at frequencies of several GHz. It has been…

Interstellar scintillation (ISS) has been established as the cause of the random variations seen at centimetre wavelengths in many compact radio sources on timescales of a day or less. Observations of ISS can be used to probe structure both…

Refraction and diffraction of incoming radio waves by the ionosphere induce time variability in the angular positions, peak amplitudes and shapes of radio sources, potentially complicating the automated cross-matching and identification of…

We use Murchison Widefield Array observations of interplanetary scintillation (IPS) to determine the source counts of point ($<$0.3 arcsecond extent) sources and of all sources with some subarcsecond structure, at 162 MHz. We have developed…

Astrophysics of Galaxies · Physics 2018-07-11 R. Chhetri , R. D. Ekers , J. Morgan , J. -P. Macquart , T. M. O. Franzen

Low-frequency observations of pulsars provide a powerful means for probing the microstructure in the turbulent interstellar medium (ISM). Here we report on high-resolution dynamic spectral analysis of our observations of the timing-array…

Solar and Stellar Astrophysics · Physics 2016-02-17 N. D. R. Bhat , S. M. Ord , S. E. Tremblay , S. J. McSweeney , S. J. Tingay

The Earth's ionosphere refracts radio signals, shifting the apparent position of radio sources. Wide-field measurements with a radio interferometer can measure the ionospheric distortion. The Murchison Widefield Array (MWA) has the ability…

Interplanetary scintillation (IPS) provides an approach for identifying the presence of sub-arcsec structures in radio sources, and very long baseline interferometry (VLBI) technique can help verify whether the IPS sources have fine…

Astrophysics of Galaxies · Physics 2021-10-27 Sumit Jaiswal , Tao An , Ailing Wang , Steven Tingay

We have conducted a blind search in 49 consecutive days of interplanetary scintillation observations made by the Murchison Widefield Array from mid-2019, with overlapping daily observations approximately East and South-East of the Sun at an…

Solar and Stellar Astrophysics · Physics 2023-10-05 A. Waszewski , J. S. Morgan , R. Chhetri , R. Ekers , M. C. M. Cheung , N. D. R Bhat , M. Johnston-Hollitt

We present a study of scintillation induced by the mid-latitude ionosphere. By implementing methods currently used in Interplanetary Scintillation studies to measure amplitude scintillation at low frequencies, we have proven it is possible…

Instrumentation and Methods for Astrophysics · Physics 2022-09-14 A. Waszewski , J. Morgan , C. H. Jordan

We present and evaluate several strategies to search for prompt, low-frequency radio emission associated with gravitational wave transients using the Murchison Widefield Array (MWA). As we are able to repoint the MWA on timescales of tens…

Instrumentation and Methods for Astrophysics · Physics 2016-10-12 D. L. Kaplan , T. Murphy , A. Rowlinson , S. D. Croft , R. B. Wayth , C. M. Trott
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