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arXiv · 2304.06350

Stochastic gravitational wave background constraints from Gaia DR3 astrometry

Santiago Jaraba·Juan García-Bellido·Sachiko Kuroyanagi·Sarah Ferraiuolo·Matteo Braglia
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Abstract

Astrometric surveys can be used to constrain the stochastic gravitational wave background (SGWB) at very low frequencies. We use proper motion data provided by Gaia DR3 to fit a generic dipole+quadrupole field. We analyse several quasar-based datasets and discuss their purity and idoneity to set constraints on gravitational waves. For the cleanest dataset, we derive an upper bound on the (frequency-integrated) energy density of the SGWB $h_{70}^2\Omega_{\rm GW}\lesssim 0.087$ for $4.2\times 10^{-18}~\mathrm{Hz}\lesssim f\lesssim 1.1\times 10^{-8}~\mathrm{Hz}$. We also reanalyse previous VLBI-based data to set the constraint $h_{70}^2\Omega_{\rm GW}\lesssim 0.024$ for $5.8\times 10^{-18}~\mathrm{Hz}\lesssim f\lesssim 1.4\times 10^{-9}~\mathrm{Hz}$ under the same formalism, standing as the best astrometric constraint on GWs. Based on our results, we discuss the potential of future Gaia data releases to impose tighter constraints.

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Santiago Jaraba, Juan García-Bellido, Sachiko Kuroyanagi, Sarah Ferraiuolo, Matteo Braglia. 2023-04-13. Stochastic gravitational wave background constraints from Gaia DR3 astrometry. https://doi.org/10.1093/mnras/stad2141

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