Estimating Solar Flux Density at Low Radio Frequencies Using a Sky Brightness Model

• Published in: Solar physics Vol. 292; no. 6; p. 1
• Main Authors: Oberoi, Divya, Sharma, Rohit, Rogers, Alan E. E.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.06.2017; Springer Nature B.V
• Subjects: Antennas; Astrophysics and Astroparticles; Atmospheric Sciences; Calibration; Correlation analysis; Estimating techniques; Fluctuations; Interferometry; Light; Physics; Physics and Astronomy; Radio frequency; Radio telescopes; Sky brightness; Sky models; Solar flares; Solar flux density; Solar physics; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Space telescopes; Telescopes; Techniques: interferometric; Sun: radio radiation
• ISSN: 0038-0938; 1573-093X
• DOI: 10.1007/s11207-017-1096-1

Sky models have been used in the past to calibrate individual low radio frequency telescopes. In this article we generalize this approach from a single antenna to a two element interferometer, and formulate the problem in a way that allows us to estimate the flux density of the Sun using the normalized cross-correlations (visibilities) measured on a low resolution interferometric baseline. For wide field-of-view instruments, typically the case at low radio frequencies, this approach can provide robust absolute solar flux calibration for well characterized antennas and receiver systems. It can provide a reliable and computationally lean method for extracting parameters of physical interest using a small fraction of the voluminous interferometric data, which can be computationally prohibitively expensive to calibrate and image using conventional approaches. We demonstrate this technique by applying it to data from the Murchison Widefield Array and assess its reliability.