p₁-mode cross-covariance functions (thin solid lines) and the weight functions (thick solid lines) calculated from a solar noise model datacube (Langfellner et al. 2015) and the window functions (dashed lines) w(t) to select the p₁-mode wave packet. Panel a): the cross-covariance function averaged over the field of view as the reference cross-covariance function, C⁰, and the weight function for amplitude W_A. Panel b): similar to a) but with the weight function for travel time W_τ. Panel c): one example cross-covariance function (at the central point of the field of view) and C⁰. The measured amplitude and travel time for this example cross-covariance are written in the panel. The cross-covariance functions in these plots are normalized by the maximum of the absolute value of C⁰. The cross-covariance functions and W_τ are dimensionless; the weight functions are calculated using the normalized cross-covariance and choosing seconds as the unit of time. In the figure, W_A is multiplied by 10² for visibility and the units are s^-1.