Speaker
Shokoufe Faraji
Description
We present a fully analytic study of fork shaped a jumps seen in
mm-VLBI closure phases and derive the first closed form expressions that connect these bifurcations to intrinsic source asymmetries.
For a two-component (dipolar) brightness model we prove: (i) a necessary and sufficient branch cut invariant that links any integer change in the closure phase property to an intervening visibility null; (ii) a jump corollary and a local antisymmetry relation that together explain the characteristic fork morphology. These results provide a calibration independent toolkit for detecting visibility nulls, quantifying low order source asymmetries, and estimating achievable precision without Monte Carlo simulation.
| Keyword-1 | closure phases |
|---|---|
| Keyword-2 | source asymmetries |
| Keyword-3 | Image moments |