Overview
- The LIGO–Virgo–KAGRA Collaboration reports in The Astrophysical Journal Letters on two late‑2024 detections, GW241011 and GW241110, with atypical spins and mass asymmetries.
- GW241011 involved roughly 17 and 7 solar‑mass black holes about 700 million light years away, with the primary among the fastest spinning ever measured and clear higher‑harmonic features.
- GW241110 featured black holes of about 16 and 8 solar masses from roughly 2.4 billion light years away, marking the first observed case of a primary spin counter to the orbital motion.
- The unusual spin orientations and unequal masses provide compelling but still developing evidence for hierarchical, second‑generation mergers in dense stellar environments.
- GW241011’s precision waveform matches the Kerr description of rotating black holes with unprecedented accuracy, while the sustained rapid spin rules out broad ranges of ultralight‑boson masses as O4 approaches roughly 300 black hole merger detections.