Cosmology with Binary Neutron Stars: Does Mass–Redshift Correlation Matter?

Next-generation gravitational-wave detectors are expected to detect millions of compact binary mergers across cosmological distances. The features of the mass distribution of these mergers, combined with gravitational-wave distance measurements, will enable precise cosmological inferences, even with...

Full description

Saved in:
Bibliographic Details
Main Authors: Soumendra Kishore Roy, Lieke A. C. van Son, Anarya Ray, Will M. Farr
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal Letters
Subjects:
Online Access:https://doi.org/10.3847/2041-8213/add34a
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850256499186597888
author Soumendra Kishore Roy
Lieke A. C. van Son
Anarya Ray
Will M. Farr
author_facet Soumendra Kishore Roy
Lieke A. C. van Son
Anarya Ray
Will M. Farr
author_sort Soumendra Kishore Roy
collection DOAJ
description Next-generation gravitational-wave detectors are expected to detect millions of compact binary mergers across cosmological distances. The features of the mass distribution of these mergers, combined with gravitational-wave distance measurements, will enable precise cosmological inferences, even without the need for electromagnetic counterparts. However, achieving accurate results requires modeling the mass spectrum, particularly considering possible redshift evolution. Binary neutron star (BNS) mergers are thought to be less influenced by changes in metallicity compared to binary black holes or neutron star–black hole mergers. This stability in their mass spectrum over cosmic time reduces the chances of introducing biases in cosmological parameters caused by redshift evolution. In this study, we use the population synthesis code COMPAS to generate astrophysically motivated catalogs of BNS mergers and explore whether assuming a nonevolving BNS mass distribution with redshift could introduce biases in cosmological parameter inference. Our findings show that despite significant variations in the BNS mass distribution across binary physics assumptions and initial conditions in COMPAS , the joint mass–redshift population can be expressed as the product of the mass distribution marginalized over redshift and the redshift distribution marginalized over masses. This enables a 2% unbiased constraint on the Hubble constant—sufficient to address the Hubble tension. Additionally, we show that in the fiducial COMPAS setup, the bias from a nonevolving BNS mass model is less than 0.5% for the Hubble parameter measured at redshift 0.4. These results establish BNS mergers as strong candidates for spectral siren cosmology in the era of next-generation gravitational-wave detectors.
format Article
id doaj-art-263177d91a974a92813fc41b078f5e7d
institution OA Journals
issn 2041-8205
language English
publishDate 2025-01-01
publisher IOP Publishing
record_format Article
series The Astrophysical Journal Letters
spelling doaj-art-263177d91a974a92813fc41b078f5e7d2025-08-20T01:56:38ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019852L3310.3847/2041-8213/add34aCosmology with Binary Neutron Stars: Does Mass–Redshift Correlation Matter?Soumendra Kishore Roy0https://orcid.org/0000-0001-9295-5119Lieke A. C. van Son1https://orcid.org/0000-0001-5484-4987Anarya Ray2https://orcid.org/0000-0002-7322-4748Will M. Farr3https://orcid.org/0000-0003-1540-8562Department of Physics and Astronomy, Stony Brook University , Stony Brook, NY 11794, USA ; soumendrakisho.roy@stonybrook.eduCenter for Computational Astrophysics, Flatiron Institute , 162 Fifth Avenue, New York, NY 10010, USA; Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08544, USACenter for Interdisciplinary Exploration and Research in Astrophysics, Northwestern University , 1800 Sherman Avenue, Evanston, IL 60201, USADepartment of Physics and Astronomy, Stony Brook University , Stony Brook, NY 11794, USA ; soumendrakisho.roy@stonybrook.edu; Center for Computational Astrophysics, Flatiron Institute , 162 Fifth Avenue, New York, NY 10010, USANext-generation gravitational-wave detectors are expected to detect millions of compact binary mergers across cosmological distances. The features of the mass distribution of these mergers, combined with gravitational-wave distance measurements, will enable precise cosmological inferences, even without the need for electromagnetic counterparts. However, achieving accurate results requires modeling the mass spectrum, particularly considering possible redshift evolution. Binary neutron star (BNS) mergers are thought to be less influenced by changes in metallicity compared to binary black holes or neutron star–black hole mergers. This stability in their mass spectrum over cosmic time reduces the chances of introducing biases in cosmological parameters caused by redshift evolution. In this study, we use the population synthesis code COMPAS to generate astrophysically motivated catalogs of BNS mergers and explore whether assuming a nonevolving BNS mass distribution with redshift could introduce biases in cosmological parameter inference. Our findings show that despite significant variations in the BNS mass distribution across binary physics assumptions and initial conditions in COMPAS , the joint mass–redshift population can be expressed as the product of the mass distribution marginalized over redshift and the redshift distribution marginalized over masses. This enables a 2% unbiased constraint on the Hubble constant—sufficient to address the Hubble tension. Additionally, we show that in the fiducial COMPAS setup, the bias from a nonevolving BNS mass model is less than 0.5% for the Hubble parameter measured at redshift 0.4. These results establish BNS mergers as strong candidates for spectral siren cosmology in the era of next-generation gravitational-wave detectors.https://doi.org/10.3847/2041-8213/add34aCosmological parametersGravitational wavesGravitational wave sourcesNeutron stars
spellingShingle Soumendra Kishore Roy
Lieke A. C. van Son
Anarya Ray
Will M. Farr
Cosmology with Binary Neutron Stars: Does Mass–Redshift Correlation Matter?
The Astrophysical Journal Letters
Cosmological parameters
Gravitational waves
Gravitational wave sources
Neutron stars
title Cosmology with Binary Neutron Stars: Does Mass–Redshift Correlation Matter?
title_full Cosmology with Binary Neutron Stars: Does Mass–Redshift Correlation Matter?
title_fullStr Cosmology with Binary Neutron Stars: Does Mass–Redshift Correlation Matter?
title_full_unstemmed Cosmology with Binary Neutron Stars: Does Mass–Redshift Correlation Matter?
title_short Cosmology with Binary Neutron Stars: Does Mass–Redshift Correlation Matter?
title_sort cosmology with binary neutron stars does mass redshift correlation matter
topic Cosmological parameters
Gravitational waves
Gravitational wave sources
Neutron stars
url https://doi.org/10.3847/2041-8213/add34a
work_keys_str_mv AT soumendrakishoreroy cosmologywithbinaryneutronstarsdoesmassredshiftcorrelationmatter
AT liekeacvanson cosmologywithbinaryneutronstarsdoesmassredshiftcorrelationmatter
AT anaryaray cosmologywithbinaryneutronstarsdoesmassredshiftcorrelationmatter
AT willmfarr cosmologywithbinaryneutronstarsdoesmassredshiftcorrelationmatter