Impact of weak lensing on bright standard siren analyses

Abstract

Gravitational waves from binary mergers at cosmological distances will experience weak lensing by large scale structure. This causes a (de-)magnification, $\mu$, of the wave amplitude, and a degenerate modification to the inferred luminosity distance $d_L$. To address this the uncertainty on $d_L$ is increased according to the dispersion of the magnification distribution at the source redshift, ${\sigma }_{\mu }$. But this term is dependent on cosmological parameters that are being constrained by gravitational wave "standard sirens", such as the Hubble parameter $H_0$, and the matter density fraction ${\Omega }_m$. ${\sigma }_{\mu }$ is also sensitive to the resolution of the simulation used for its calculation. Tension in the measured value of $H_0$ from independent datasets, and the present use of outdated cosmological simulations, suggest ${\sigma }_{\mu }$ could be underestimated. We consider two classes of standard siren, supermassive black hole binary and binary neutron star mergers. Underestimating $H_0$ and ${\Omega }_m$ when calculating ${\sigma }_{\mu }$ increases the probability of finding a residual lensing bias on these parameters greater than $1\sigma$ by 1.5-3 times. Underestimating ${\sigma }_{\mu }$ by using low resolution/small sky-area simulations can also significantly increase the probability of biased results. For neutron star mergers, the spread of possible biases is 0.25 km/s/Mpc, comparable to the forecasted uncertainty. Left uncorrected this effect limits the use of BNS mergers for precision cosmology. For supermassive black hole binaries, the spread of possible biases on $H_0$ is significant, 5 km/s/Mpc, but $O(200)$ observations are needed to reduce the variance below the bias. To achieve accurate sub-percent level precision on cosmological parameters using standard sirens, first much improved knowledge on the form of the magnification distribution and its dependence on cosmology is needed.

18 pages, 8 figures

References in corpus (19)

• Formation of Supermassive Black Holes by Direct Collapse in Pregalactic Halos
• Scientific Objectives of Einstein Telescope
• The evolution of massive black hole seeds
• Determination of Dark Energy by the Einstein Telescope: Comparing with CMB, BAO and SNIa Observations
• Full-sky Gravitational Lensing Simulation for Large-area Galaxy Surveys and Cosmic Microwave Background Experiments
• Reducing the weak lensing noise for the gravitational wave Hubble diagram using the non-Gaussianity of the magnification distribution
• Do stochastic inhomogeneities affect dark-energy precision measurements?
• Beyond Concordance Cosmology with Magnification of Gravitational-Wave Standard Sirens
• $\text{GWFAST}$: a Fisher information matrix Python code for third-generation gravitational-wave detectors
• A Program for Multi-Messenger Standard Siren Cosmology in the Era of LIGO A+, Rubin Observatory, and Beyond
• Non-Gaussian estimates of tensions in cosmological parameters
• Massive black hole binaries in LISA: multimessenger prospects and electromagnetic counterparts
• Lensing and Supernovae: Quantifying The Bias on the Dark Energy Equation of State
• Weakly Lensed Gravitational Waves: Probing Cosmic Structures with Wave-Optics Features
• Probing wave-optics effects and low-mass dark matter halos with lensing of gravitational waves from massive black holes
• Generalized covariant prescriptions for averaging cosmological observables
• Lensing Effects on Gravitational Waves in a Clumpy Universe -Effects of Inhomogeneity on the Distance-Redshift Relation-
• The skewness of the distance-redshift relation in $\Lambda$CDM
• Multi-messenger astronomy with a Southern-Hemisphere gravitational-wave observatory

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• The Science of the Einstein Telescope
• Multi-messenger Gravitational Lensing
• Gravitational Lensing of Gravitational Waves from Astrophysical Sources: Theory, Detection, and Applications
• Weak lensing of bright standard sirens: prospects for ${\sigma }_8$
• Strong-lensing rates of massive black hole binaries in LISA