Speaker
Description
As stellar intensity interferometry is expanding its target catalogue to more and more complex star systems, interpretation of the measured data needs to take into account more aspects of such observations. The observed coherence of targets with asymmetries cannot be described as a 1-dimentional function, i.e. as a function of projected distance between telescopes. Instead, converting projected baselines to vectors in the u-v plane allows the reconstruction of e.g. the oblateness of a rapidly rotating star, especially at high telescope multiplicity due to denser coverage of the plane. In the case of binary systems, the orbital phase of the stars relative to each other needs to also be considered in the analysis. In order to simulate the characteristics of spherically asymmetric targets and binary systems, we have measured the coherence of pseudothermal light directed through shaped and binary pinholes in the laboratory. Telescopes were substituted by optical fibers in a fiber array to allow for a dense u-v-plane coverage.
Through these measurements we have gained an understanding of how measurement results could look for stars flattened by their own rotation or binary systems sampled at various array densities, and we tested which analysis tools are the most promising in reconstructing the observed target geometries. Further, we are analyzing the systematics related to such kind of measurements in order to determine the precision which can be reached in astronomical observations via intensity interferometry.
