Noise in Maps of the Sun at Radio Wavelengths I: Theoretical Considerations

TL;DR

This paper develops a theoretical framework for understanding noise, especially self-noise, in radio maps of the Sun created by Fourier synthesis techniques, considering various observational configurations.

Contribution

It provides a comprehensive theoretical analysis of noise in radio solar maps, focusing on self-noise and its distribution across different interferometric setups.

Findings

Noise behavior analyzed for single dish, two-element, and n-element arrays.

Implications of self-noise for solar radio observations discussed.

Framework aids in understanding noise limitations in radio solar imaging.

Abstract

The Sun is a powerful source of radio emissions, so much so that, unlike most celestial sources, this emission can dominate the system noise of radio telescopes. We outline the theory of noise in maps formed by Fourier synthesis techniques at radio wavelengths, with a focus on self-noise: that is, noise due to the source itself. As a means of developing intuition we consider noise for the case of a single dish, a two-element interferometer, and an n-element array for simple limiting cases. We then turn to the question of the distribution of noise on a map of an arbitrary source observed at radio wavelengths by an n-element interferometric array. We consider the implications of self-noise for observations of the Sun in a companion paper.