Testing gravity with gravitational waves × electromagnetic probes cross-correlations

Journal of Cosmology and Astroparticle Physics, vol. 2023, pp. 010

Abstract

Abstract In a General Relativistic framework, Gravitational Waves (GW) and Electromagnetic (EM) waves are expected to respond in the same way to the effects of matter perturbations between the emitter and the observer. A different behaviour might be a signature of alternative theories of gravity. In this work we study the cross-correlation of resolved GW events (from compact objects mergers detected by the Einstein Telescope, either assuming or excluding the detection of an EM counterpart) and EM signals (coming both from the Intensity Mapping of the neutral hydrogen distribution and resolved galaxies from the SKA Observatory), considering weak lensing, angular clustering and their cross term (L × C) as observable probes. Cross-correlations of these effects are expected to provide promising information on the behaviour of these two observables, hopefully shedding light on beyond GR signatures. We perform a Fisher matrix analysis with the aim of constraining the {μ 0, η 0, Σ 0} parameters, either opening or keeping fixed the background parameters {w 0, w a}. We find that, although lensing-only forecasts provide significantly unconstrained results, the combination with angular clustering and the cross-correlation of all three considered tracers (GW, IM, resolved galaxies) leads to interesting and competitive constraints. This offers a novel and alternative path to both multi-tracing opportunities for Cosmology and the Modified Gravity sector.

Authors 4

1. Giulio Scelfo corresponding

   Scuola Internazionale Superiore di Studi Avanzati · Istituto Nazionale di Fisica Nucleare, Sezione di Trieste · Institute for Fundamental Physics of the Universe

   Affiliation as printed

   IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, Trieste 34151, Italy

   INFN, Sezione di Trieste, Via Bonomea 265, Trieste 34136, Italy

   SISSA, Via Bonomea 265, Trieste 34136, Italy

2. Maria Berti corresponding

   Scuola Internazionale Superiore di Studi Avanzati · Istituto Nazionale di Fisica Nucleare, Sezione di Trieste · Institute for Fundamental Physics of the Universe

   Affiliation as printed

   IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, Trieste 34151, Italy

   INFN, Sezione di Trieste, Via Bonomea 265, Trieste 34136, Italy

   SISSA, Via Bonomea 265, Trieste 34136, Italy

3. Alessandra Silvestri corresponding Aachen Institute Lorentz

   Leiden University

   Affiliation as printed

   Institute Lorentz, Leiden University, P.O. Box 9506, Leiden 2300 RA, The Netherlands

4. Matteo Viel corresponding

   Scuola Internazionale Superiore di Studi Avanzati · Trieste Astronomical Observatory · Istituto Nazionale di Fisica Nucleare, Sezione di Trieste · Institute for Fundamental Physics of the Universe · National Institute for Astrophysics

   Affiliation as printed

   IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, Trieste 34151, Italy

   INAF/OATS, Osservatorio Astronomico di Trieste, via Tiepolo 11, Trieste 34143, Italy

   INFN, Sezione di Trieste, Via Bonomea 265, Trieste 34136, Italy

   SISSA, Via Bonomea 265, Trieste 34136, Italy