Overview
- Two unusual events announced by the LIGO–Virgo–KAGRA Collaboration, GW241011 and GW241110, feature unequal masses and extreme spins including a retrograde primary and one of the fastest rotators observed.
- A new population analysis on arXiv identifies a low-mass, rapidly and isotropically spinning subpopulation that includes these events and suggests second-generation black holes may peak near about 16 solar masses.
- The LVK team used the high-quality GW241011 signal to test spacetime deformation around a spinning black hole, finding strong agreement with Kerr’s prediction and setting stringent constraints.
- The same analysis of GW241011 rules out a wide range of ultralight boson masses by showing the primary retained rapid rotation long after formation.
- Independent GRMHD simulations published in The Astrophysical Journal Letters show magnetic fields can expel stellar mass to form high-spin black holes in the pair-instability gap and predict potentially observable gamma-ray bursts, while separate research cautions that current waveform models can bias spin inferences for asymmetric, precessing binaries.