Polarization degree and angle as a function of energy. Errors are at 1σ confidence level, while upper limits correspond to the 99% confidence level. Blue lines show linear fits to the PD data, with resulting p-values. Gray points represent the PAs corresponding to the PD upper limits. Orange lines indicate the average PAs in the 2–8 keV range, with associated 1σ error highlighted by the orange regions. (a) Cyg X-2. (b) XTE J1701–462 (Obs. I). (c) XTE J1701–462 (Obs. II). (d) GX 5–1 (Obs. I). (e) GX 5–1 (Obs. II). (f) Sco X-1. (g) GX 340+0 (Obs. I). (h) GX 340+0 (Obs. II). (i) GX 349+2.