Overview
- A paper in The Astrophysical Journal Letters reports detailed analyses of GW241011 (October 11, 2024) and GW241110 (November 10, 2024) observed by the LIGO–Virgo–KAGRA network.
- GW241011 involved black holes of about 17 and 7 solar masses roughly 700 million light-years away, with the primary among the fastest rotators measured and a clearly detected higher harmonic that strengthened Kerr tests.
- GW241110 featured black holes of about 16 and 8 solar masses around 2.4 billion light-years distant, with the primary spinning opposite the orbital motion in the first confirmed retrograde spin for a merging binary.
- The unequal masses together with extreme and unusual spin orientations provide compelling evidence for hierarchical formation in dense stellar environments where repeated mergers occur.
- Results validate general relativity with unprecedented accuracy and rule out a broad range of ultralight boson masses based on the persistent rapid rotation in GW241011, as the O4 campaign approaches ~300 recorded mergers.