English

Exploring Hierarchical Merger Scenarios for GW241011 and GW241110

High Energy Astrophysical Phenomena 2026-07-06 v1

Abstract

GW241011 and GW241110 are asymmetric binary black hole mergers with rapidly spinning primaries, unequal component masses, and nonzero spin--orbit tilts, making them natural candidates for hierarchical mergers. We use a Bayesian framework to compare a fiducial first-generation (1G+1G) binary black hole population with second-generation plus first-generation (2G+1G) hierarchical merger models in star clusters and active galactic nucleus (AGN) disks. Both events favor the 2G+1G interpretation over the 1G+1G hypothesis, with lnB1G+1G2G+1G6.5\ln\mathcal{B}^{\rm 2G+1G}_{\rm 1G+1G}\simeq6.5--8.68.6 for GW241011 and lnB1G+1G2G+1G3.0\ln\mathcal{B}^{\rm 2G+1G}_{\rm 1G+1G}\simeq3.0--4.54.5 for GW241110, depending on the waveform model and assumed environment. The AGN disk models yields slightly larger evidence than the star cluster models, mainly due to their spin tilt distribution, but the data do not provide a decisive environmental classification. We further consider a third-generation plus first-generation (3G+1G) interpretation, but it is not robustly preferred over 2G+1G scenarios. Finally, we also search for optical counterparts by examining AGNs within the three-dimensional localization volumes using ZTF and ATLAS forced photometry, and find one candidate source with weak flare, which might be associated with GW241110 event.

Keywords

Cite

@article{arxiv.2607.04663,
  title  = {Exploring Hierarchical Merger Scenarios for GW241011 and GW241110},
  author = {Lei He and Liang-Gui Zhu and Zheng-Yan Liu and Rui Niu and Chao Wei and Ken Chen and Wen Zhao},
  journal= {arXiv preprint arXiv:2607.04663},
  year   = {2026}
}

Comments

11 pages, 4 figures