Dynamic spectra and extended emission observable Q1 in Stokes-V (|V′ |) for a scaling parameter of α = 10⁻⁴. Panels a: dynamic spectra for the ON-beam (top panel) and the OFF-beam (bottom panel). Panel b: Q1a (time-series integrated over all frequencies). Panel c: Q1b (integrated spectrum summed over all times). See Sect. 4.3 for a detailed description of each observable. For all plots the black squares are the ON-beam, red diamonds are the OFF-beam, and black circles are the difference between beams. The error bars in panels b and c were calculated assuming pure Gaussian noise ().