Image Details
GWTC-4.0: Population Properties of Merging Compact Binaries
A. G. Abac et al 2026 The Astrophysical Journal Letters 1005 .
Caption: Figure 9.
Marginal χeff (left panel) and χp (right panel) distributions. The solid lines show the median of each inferred distribution, and the shaded regions show the 90% credible intervals. The GWTC-4.0 results under the SKEW-NORMAL EFFECTIVE SPIN model are shown in red; the GWTC-3.0 results under the GAUSSIAN EFFECTIVE SPINS model are shown in purple (dashed). The histogram inset in the left panel shows the skew parameter ϵ for the SKEW-NORMAL EFFECTIVE SPIN model. There is significant preference for a skewed χeff distribution, indicated by ϵ < 0 with 99.5% credibility.
© 2026. The Author(s). Published by the American Astronomical Society.