Double Neutron Star Mergers and Fast Blue Optical Transients: A Circumbinary Disk Connection
Abstract
Post-common-envelope evolution (CEE) circumbinary disks (CBDs) form when part of the ejected envelope remains bound and circularizes around the stripped core and its companion. Leveraging results of scale-free hydrodynamical simulations, we develop a framework to model the effect of such disks on subsequent binary evolution, and implement it in the population synthesis code COMPAS. Applying our framework to double neutron star (DNS) merger progenitors, we find that CBDs generally induce substantial orbital shrinkage, changing the merging DNS population and lowering the overall merger rate. We explore an extensive grid of binary-evolution and disk models, and find that CBD interactions reduce the DNS merger rate by up to 28%, primarily through 'premature' mergers between the neutron star (NS) and the giant's core. These mergers may power luminous fast blue optical transients (LFBOTs), occurring at a fiducial rate of ≃11 Gpc−3 yr−1. Our results indicate that natal kicks contribute little to LFBOT offsets, and that they should be associated with young stellar populations, though not necessarily active star-forming regions. Since LFBOT progenitors would otherwise produce short-delay DNS mergers, CBDs further challenge DNS mergers as the source of early r-process enrichment. For surviving DNS mergers, accretion from the disk leads to higher chirp masses, potentially explaining the puzzling mass of GW190425. Our framework provides a general tool for studying CBD-binary interactions in post-CEE systems.
Related
- Circumbinary discs as the origin of circumstellar material around interacting H-poor supernovae and fast blue optical transients
- Exploring the connection between Fast Radio Bursts and binary neutron star mergers
- Luminous Fast Blue Optical Transients as “Failed” Gravitational-wave Sources: Helium Core–Black Hole Mergers Following Delayed Dynamical Instability
- Constraining equation of state of neutron star using neutron star-black hole mergers
- Tidal disruption or plunge: the role of neutron star internal structure in black hole-neutron star mergers
BibTeX
@misc{grichener2026double,
title = {{Double Neutron Star Mergers and Fast Blue Optical Transients: A Circumbinary Disk Connection}},
author = {Aldana Grichener and Ruggero Valli and Mathieu Renzo and Ilya Mandel and Kaitlin M. Kratter and Magdalena Siwek and Koushik Sen and Neev Shah},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.07326},
eprint = {2611.07326},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.07326},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Double Neutron Star Mergers and Fast Blue Optical Transients: A Circumbinary Disk Connection
AU - Aldana Grichener
AU - Ruggero Valli
AU - Mathieu Renzo
AU - Ilya Mandel
AU - Kaitlin M. Kratter
AU - Magdalena Siwek
AU - Koushik Sen
AU - Neev Shah
PY - 2026
DA - 2026/11/05
PB - arXiv
DO - 10.48550/arxiv.2611.07326
UR - https://arxiv.org/abs/2611.07326
AB - Post-common-envelope evolution (CEE) circumbinary disks (CBDs) form when part of the ejected envelope remains bound and circularizes around the stripped core and its companion. Leveraging results of scale-free hydrodynamical simulations, we develop a framework to model the effect of such disks on subsequent binary evolution, and implement it in the population synthesis code COMPAS. Applying our framework to double neutron star (DNS) merger progenitors, we find that CBDs generally induce substantial orbital shrinkage, changing the merging DNS population and lowering the overall merger rate. We explore an extensive grid of binary-evolution and disk models, and find that CBD interactions reduce the DNS merger rate by up to 28%, primarily through 'premature' mergers between the neutron star (NS) and the giant's core. These mergers may power luminous fast blue optical transients (LFBOTs), occurring at a fiducial rate of ≃11 Gpc^−3 yr^−1. Our results indicate that natal kicks contribute little to LFBOT offsets, and that they should be associated with young stellar populations, though not necessarily active star-forming regions. Since LFBOT progenitors would otherwise produce short-delay DNS mergers, CBDs further challenge DNS mergers as the source of early r-process enrichment. For surviving DNS mergers, accretion from the disk leads to higher chirp masses, potentially explaining the puzzling mass of GW190425. Our framework provides a general tool for studying CBD-binary interactions in post-CEE systems.
ER -