Image Details
Caption: Figure 6.
Posteriors for the two population model. Top left: the posterior for κ1 (subpopulation with semimajor axis a ≤ acutoff). The mode and 68% HDPI is ﹩{\kappa }_{1}=4{8}_{-32}^{+194}﹩, corresponding to spin–orbit angles peaking at ﹩\psi ={{8}_{-4}^{+6}}^\circ ﹩. Top right: 1000 ψ distributions shown as green curves, each corresponding to samples from the κ1 posterior. The black curve is the ψ distribution for κ1 = 48, peaking at 10°, indicating highly aligned spin–orbit angles. Bottom: same as the top two panels, but for κ2 (when a > acutoff). The mode and 68% HDPI is ﹩{\kappa }_{2}={6}_{-2}^{+4}﹩, corresponding to peak ﹩\psi ={2{3}_{-5}^{+5}}^\circ ﹩, indicating weak but not random spin–orbit alignment.
© 2026. The Author(s). Published by the American Astronomical Society.