Interferometric Visibility of a Scintillating Source: Statistics at the Nyquist Limit

TL;DR

This paper derives the statistical distribution of interferometric visibility for scintillating sources, considering spectral resolution, averaging effects, and source extension, aiding interpretation of pulsar observations at meter wavelengths.

Contribution

It provides a comprehensive model of visibility statistics under various observational conditions, including strong scintillation and intrinsic source variability.

Findings

Distribution exhibits a broad 'skirt' due to scintillation and self-noise

Results enable better interpretation of pulsar interferometric data

Accounts for spectral resolution and source extension effects

Abstract

We derive the distribution of interferometric visibility for a source exhibiting strong diffractive scintillation, with particular attention to spectral resolution at or near the Nyquist limit. We also account for arbitrary temporal averaging, intrinsic variability within the averaging time, and the possibility of spatially-extended source emission. We demonstrate that the interplay between scintillation and self-noise induces several remarkable features, such as a broad "skirt" in the visibility distribution. Our results facilitate the interpretation of interferometric observations of pulsars at meter and decimeter wavelengths.