GW241011 and GW241110: Exploring Binary Formation and Fundamental Physics with Asymmetric, High-Spin Black Hole Coalescence

TL;DR

This paper reports the detection of two binary black hole mergers with high spins and misaligned orbits, providing insights into their formation in dense stellar environments and testing fundamental physics constraints.

Contribution

First observation of high-spin, asymmetric binary black hole mergers with implications for formation channels and fundamental physics constraints.

Findings

Detected GW241011 and GW241110 with high spins and misalignment.

Provided constraints on black hole Kerr nature and gravitational-wave multipolar structure.

Set limits on ultralight bosons in the mass range 10^{-13}--10^{-12} eV.

Abstract

We report the observation of gravitational waves from two binary black hole coalescences during the fourth observing run of the LIGO--Virgo--KAGRA detector network, GW241011 and GW241110. The sources of these two signals are characterized by rapid and precisely measured primary spins, non-negligible spin--orbit misalignment, and unequal mass ratios between their constituent black holes. These properties are characteristic of binaries in which the more massive object was itself formed from a previous binary black hole merger, and suggest that the sources of GW241011 and GW241110 may have formed in dense stellar environments in which repeated mergers can take place. As the third loudest gravitational-wave event published to date, with a median network signal-to-noise ratio of $36.0$, GW241011 furthermore yields stringent constraints on the Kerr nature of black holes, the multipolar structure of gravitational-wave generation, and the existence of ultralight bosons within the mass range $10^{-13}$--$10^{-12}$ eV.