H. R. Butcher

Sub-arcsecond imaging with the International LOFAR Telescope I. Foundational calibration strategy and pipeline

Leah K. Morabito, Neal J Jackson, S. Mooney, Frits Sweijen et autres

[abridged] The International LOFAR Telescope is an interferometer with stations spread across Europe. With baselines of up to ~2,000 km, LOFAR has the unique capability of achieving sub-arcsecond resolution at frequencies below 200 MHz, although this is technically and logistically challenging. Here …

Sub-arcsecond imaging with the International LOFAR Telescope: II. Completion of the LOFAR Long-Baseline Calibrator Survey

Neal J Jackson, Shruti Badole, John S. Morgan, Rajan Chhetri et autres

The Low-Frequency Array (LOFAR) Long-Baseline Calibrator Survey (LBCS) was conducted between 2014 and 2019 in order to obtain a set of suitable calibrators for the LOFAR array. In this paper we present the complete survey, building on the preliminary analysis published in …

Sub-arcsecond imaging with the International LOFAR Telescope

Neal J Jackson, Shruti Badole, John S. Morgan, Rita Chhetri et autres

The Low-Frequency Array (LOFAR) Long-Baseline Calibrator Survey (LBCS) was conducted between 2014 and 2019 in order to obtain a set of suitable calibrators for the LOFAR array. In this paper, we present the complete survey, building on the preliminary analysis published in …

gb, au, lv, nl, ie, es, de, in, it, be, fr, us, pl, Afrique du Sud (code pays fourni par la source)

Sub-arcsecond imaging with the International LOFAR Telescope

Leah K. Morabito, Neal J Jackson, S. Mooney, Frits Sweijen et autres

The International LOFAR Telescope is an interferometer with stations spread across Europe. With baselines of up to ~2000 km, LOFAR has the unique capability of achieving sub-arcsecond resolution at frequencies below 200 MHz. However, it is technically and logistically challenging to process …

gb, ie, nl, se, de, it, au, es, fr, Afrique du Sud, in, be, us, pl (code pays fourni par la source)

A LOFAR Observation of Ionospheric Scintillation from Two Simultaneous\n Travelling Ionospheric Disturbances

R. A. Fallows, Biagio Forte, I. Astin, Tom Allbrook et autres

This paper presents the results from one of the first observations of\nionospheric scintillation taken using the Low-Frequency Array (LOFAR). The\nobservation was of the strong natural radio source Cas A, taken overnight on\n18-19 August 2013, and exhibited moderately strong scattering effects in\ndynamic spectra …

Cassiopeia A, Cygnus A, Taurus A, and Virgo A at ultra-low radio frequencies

F. de Gasperin, Jacco Vink, J. P. McKean, A. Asgekar et autres

Context. The four persistent radio sources in the northern sky with the highest flux density at metre wavelengths are Cassiopeia A, Cygnus A, Taurus A, and Virgo A; collectively they are called the A-team. Their flux densities at ultra-low frequencies (< 100 …

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VizieR Online Data Catalog: CasA, CygA, TauA, VirA 30MHz & 77MHz models (de Gasperin+, 2020)

F. de Gasperin, J. Vink, J. P. McKean, A. Asgekar et autres

A LOFAR observation of ionospheric scintillation from two simultaneous travelling ionospheric disturbances

Richard Andrew Fallows, Biagio Forte, I. Astin, Tom Allbrook et autres

This paper presents the results from one of the first observations of ionospheric scintillation taken using the Low-Frequency Array (LOFAR). The observation was of the strong natural radio source Cassiopeia A, taken overnight on 18–19 August 2013, and exhibited moderately strong scattering …

nl, gb, pl, de, in, au, fr, be, Afrique du Sud, ae, se (code pays fourni par la source)

A LOFAR Observation of Ionospheric Scintillation from Two Simultaneous Travelling Ionospheric Disturbances

Richard Andrew Fallows, Biagio Forte, I. Astin, Tom Allbrook et autres

This paper presents the results from one of the first observations of ionospheric scintillation taken using the Low-Frequency Array (LOFAR). The observation was of the strong natural radio source Cas A, taken overnight on 18-19 August 2013, and exhibited moderately strong scattering …

de (code pays fourni par la source)

Needle-like structures discovered on positively charged lightning branches

Brian M. Hare, Olaf Scholten, J. R. Dwyer, T. N. G. Trinh et autres

nl, be, us, de, au, gb, fr, pl, Afrique du Sud (code pays fourni par la source)

Shock location and CME 3D reconstruction of a solar type II radio burst with LOFAR

Pietro Zucca, Diana E. Morosan, A. P. Rouillard, Richard Andrew Fallows et autres

Context. Type II radio bursts are evidence of shocks in the solar atmosphere and inner heliosphere that emit radio waves ranging from sub-meter to kilometer lengths. These shocks may be associated with coronal mass ejections (CMEs) and reach speeds higher than the …

nl, ie, fr, be, de, gb, pl, in, au, no, us, Afrique du Sud, se (code pays fourni par la source)

Low-frequency radio absorption in Cassiopeia A

Maria Arias, Jacco Vink, F. de Gasperin, P. Salas et autres

Context.Cassiopeia A is one of the best-studied supernova remnants. Its bright radio and X-ray emission is due to shocked ejecta. Cas A is rather unique in that the unshocked ejecta can also be studied: through emission in the infrared, the radio-active decay …

nl, de, au, gb, fr, us, pl, no, Afrique du Sud, se (code pays fourni par la source)