4D Data Cubes from Radio-Interferometric Spectroscopic Snapshot Imaging

Abstract

The new generation of low radio-frequency interferometric arrays have enabled the imaging of the solar corona at high spectro-temporal resolutions and sensitivity. In this article we introduce and implement a formalism to generate flux density and brightness temperature ($T_{\mathrm{B}}$) maps from such images, using independently obtained disc-integrated solar flux density dynamic spectra. These images collectively generate a 4D data cube, with axes spanning angular coordinates ($\theta ,\varphi$), frequency ($\nu$) and time ($t$). This 4D data cube is the most informative data product which can be generated from interferometric radio data. It will allow us to track solar emission simultaneously in these four dimensions. We also introduce SPatially REsolved Dynamic Spectra (SPREDS), named in analogy to the usual dynamic spectra. For any arbitrary region, (${\theta }_i,{\varphi }_j$), in the maps, these 2D projections of the 4D data cube correspond to the dynamic spectrum of emission arising from there. We show examples of these data products using observations from the Murchison Widefield Array (MWA). These are also the first calibrated solar maps from the MWA.

References in corpus (3)

• The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation
• LOFAR tied-array imaging of Type III solar radio bursts
• The Murchison Widefield Array Correlator

Cited by in corpus (4)

• Science with the Murchison Widefield Array: Phase I Results and Phase II Opportunities
• Unsupervised generation of high dynamic range solar images: A novel algorithm for self-calibration of interferometry data
• Possible Detection of Subsecond-period Propagating Magnetohydrodynamics Waves in Post-reconnection Magnetic Loops during a Two-ribbon Solar Flare
• Discovery of correlated evolution in solar noise storm source parameters: Insights on magnetic field dynamics during a microflare