https://doi.org/10.1140/epjc/s10052-025-15114-9
Regular Article - Theoretical Physics
Multi-messenger standard-siren cosmology for third-generation gravitational-wave detectors: forecasts considering observations of gamma-ray bursts and kilonovae
1
Liaoning Key Laboratory of Cosmology and Astrophysics, College of Sciences, Northeastern University, 110819, Shenyang, China
2
MOE Key Laboratory of Data Analytics and Optimization for Smart Industry, Northeastern University, 110819, Shenyang, China
3
National Frontiers Science Center for Industrial Intelligence and Systems Optimization, Northeastern University, 110819, Shenyang, China
Received:
25
April
2025
Accepted:
24
November
2025
Published online:
5
January
2026
In the third-generation (3G) gravitational-wave (GW) detector era, GW multi-messenger observations for binary neutron star merger events can exert significant effects on exploring the cosmic expansion history. Extending a previous work, we explore the potential of 3G GW standard siren observations in cosmological parameter estimation by considering their associated electromagnetic (EM) counterparts, including 
-ray burst (GRB) coincidence observations by the Gravitational Wave High-energy Electromagnetic Counterpart All-sky Monitor and GW-triggered target-of-opportunity observations of kilonovae by different optical survey projects. During an assumed 10-year observation, we predict that the number of detectable GW-kilonova events is 
with redshifts below 
under the GW detector network and Large Synoptic Survey Telescope in the i band, which is more than three times that of GW-GRB detections. For the cosmological analysis, we find that with the inclusion of GW-kilonova detections, the constraints on cosmological parameters from GW-EM detections are significantly improved compared to those from GW-GRB detections. In particular, GW-EM detections can tightly constrain the Hubble constant with precision ranging from 
to 
. Moreover, GW multi-messenger observations can effectively break the cosmological parameter degeneracies generated by the typical EM observations, CMB+BAO+SN (CBS). The combination of CBS and GW-EM can tightly constrain the equation-of-state parameters of dark energy w in the wCDM model and 
in the 
CDM model with precision of 
and 
, respectively, meeting the standard of precision cosmology. In conclusion, GW multi-messenger observations could play a crucial role in helping solve the Hubble tension and probing the fundamental nature of dark energy.
© The Author(s) 2026
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