New Coralie RV data for QZ Nor (N = 125). The large panel shows the phased RV curve, distinguishing data from different epochs by symbol style and color. The two right-hand panels provide close-ups around maximum (upper) and minimum RV (lower), and show the median RV uncertainty as a blue errorbar. The bottom panel shows residuals around an “average” Fourier series model fit to the combined data set (fit procedure described in Anderson et al. 2013).

Analogous to Fig. A.1 using RV data for V335 Puppis (N = 95).

Analogous to Fig. A.1 using RV data for RS Puppis (N = 439). RS Puppis also exhibits significant random cycle-to-cycle fluctuations in pulsation period (Berdnikov et al. 2009). As the close-up panels demonstrate, these random period fluctuations occur in addition to the modulation of the RV amplitude.

Fit residuals from the epochs (E₁ and E₂) used to estimate the impact on BW distances for all four Cepheids, cf. Table 1. For ℓ Car and RS Pup, both the cycle-to-cycle and longer timescales are shown. The earlier epoch is represented by green x markers, the later epoch by black open circles. For each epoch, the rms around the fit and median measurement uncertainty, ⟨ σ ⟩, are printed in the corresponding panel, indicating excellent fits.