Image Details
GWTC-4.0: An Introduction to Version 4.0 of the Gravitational-Wave Transient Catalog
A. G. Abac et al 2025 The Astrophysical Journal Letters 995 .
Caption: Figure 5.
Relationship between the orbital elements and the GW coordinate frame. The direction from the source to Earth is N, and the vector X defines a reference direction on the transverse plane (the plane of the sky). The inclination ι is the angle between N and the orbital angular momentum vector L. The longitude of the ascending node of the orbit Ω is the angle on the plane of the sky between X and the ascending node ♌, N × L. The angle Ω is degenerate with the polarization angle ψ. The orbit of the primary about the center of mass of the system is shown. The orbital phase ϕ is the angle on the orbital plane between the ascending node and position vector of the primary relative to the center of mass. For an eccentric orbit, the distance of the primary from the center of mass at periapsis is rp, and the argument of the periapsis ω for the primary is the angle on the orbital plane between the ascending node and the position vector of the primary at periapsis.
© 2025. The Author(s). Published by the American Astronomical Society.