Strip Integration in Radio Astronomy

TLDR

Strip integration refers to the transformation from the true radio‑wave distribution to the measured value when a long, narrow aerial beam scans a source, and it is treated as a special case of two‑dimensional aerial smoothing with a rotating beam. The paper proposes a method to reconstruct the principal solution of the strip‑integration problem from observed data. The method relies on a finite set of scans to compute the principal solution of the strip‑integration equation. The results demonstrate that resolution is governed by the beam’s narrow‑dimension profile, that a line strip yields complete reconstruction with scans in all directions, and that in general a principal solution exists and can be obtained from a finite number of scans.

Abstract

When a celestial source of radio waves is scanned with an aerial beam which is much longer than the source in one direction but suitably narrow in the other, the transformation from the true distribution to the measured value is referred to as strip integration. It is here treated as a special case of two-dimensional aerial smoothing in which the aerial beam is allowed to spin about its centre as it moves about the sky. It is shown that the resolution obtainable is set by the cross-sectional profile of the strip beam in the narrow dimension. Thus, when the strip reduces to a line, the resolution is complete and full reconstruction of the true distribution is possible; but scans must be made in all directions. In the general case it is shown that there is a principal solution, and that a finite number of scans suffices to determine it. A method is presented for reconstructing the principal solution from the observed data.