Title: Testing modified gravity at cosmological distances with LISA standard sirens

Abstract

Modifications of General Relativity leave their imprint both on the cosmic expansion history through a non-trivial dark energy equation of state, and on the evolution of cosmological perturbations in the scalar and in the tensor sectors. Specifically, the modification in the tensor sector gives rise to a notion of gravitational-wave (GW) luminosity distance, different from the standard electromagnetic luminosity distance, that can be studied with standard sirens at GW detectors such as LISA or third-generation ground based experiments. Here, we discuss the predictions for modified GW propagation from some of the best studied theories of modified gravity, such as Horndeski or the more general degenerate higher order scalar-tensor (DHOST) theories, non-local infrared modifications of gravity, bigravity theories and the corresponding phenomenon of GW oscillation, as well as theories with extra or varying dimensions. We show that modified GW propagation is a completely generic phenomenon in modified gravity. We then use a simple parametrization of the effect in terms of two parameters (Ξ ₀, n), that is shown to fit well the results from a large class of models, to study the prospects of observing modified GW propagation using supermassive black hole binaries as standard sirens with LISA. We build mockmore » source catalogs and perform detailed Markov Chain Monte Carlo studies of the likelihood obtained from LISA standard sirens alone, as well as by combining them with CMB, BAO and SNe data to reduce the degeneracies between cosmological parameters. We find that the combination of LISA with the other cosmological datasets allows one to measure the parameter Ξ ₀ that characterizes modified GW propagation to the percent level accuracy, sufficient to test several modified gravity theories. LISA standard sirens can also improve constraints on GW oscillations induced by extra field content by about three orders of magnitude relative to the current capability of ground detectors. We also update the forecasts on the accuracy on H ₀ and on the dark-energy equation of state using more recent estimates for the LISA sensitivity.« less

Authors:

Belgacem, Enis ^[1]; Calcagni, Gianluca ^[2]; Crisostomi, Marco ^[3]; Dalang, Charles ^[1]; Dirian, Yves ^[4]; Ezquiaga, Jose María ^[5]; Fasiello, Matteo ^[6]; Foffa, Stefano ^[1]; Ganz, Alexander ^[7]; García-Bellido, Juan ^[5]; Lombriser, Lucas ^[1]; Maggiore, Michele ^[1]; Tamanini, Nicola ^[8]; Tasinato, Gianmassimo ^[9]; Zumalacárregui, Miguel ^[10]; Barausse, Enrico ^[11]; Bartolo, Nicola ^[12]; Bertacca, Daniele ^[7]; Klein, Antoine ^[13]; Matarrese, Sabino ^[14] more »; Sakellariadou, Mairi ^[15] « less

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+ Show Author Affiliations

1. Univ. of Geneva (Switzerland). Département de Physique Théorique and Center for Astroparticle Physics
2. Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Instituto de Estructura de la Materia
3. Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France). Inst. de Biologie et Technologies de Saclay et CNRS; Astrophysique Instrumentation Modélisation (AIM), Gif-sur-Yvette (France); Univ. Paris-Sud, Orsay (France). Lab. de Physique Théorique
4. Univ. of Geneva (Switzerland). Département de Physique Théorique and Center for Astroparticle Physics; Univ. of Zurich (Switzerland). Inst. for Computational Science
5. Univ. Autonoma de Madrid (Spain). Dept. de Fisica Teorica
6. Univ. of Portsmouth (United Kingdom). Inst. of Cosmology and Gravitation
7. Univ. degli Studi di Padova (Italy). Dipartimento di Fisica e Astronomia "G. Galilei"; Istituto Nazionale di Fisica Nucleare (INFN), Padova (Italy)
8. Max-Planck-Institut für Gravitationsphysik, Potsdam-Golm (Germany). Albert-Einstein-Inst.
9. Swansea Univ. (United Kingdom). Dept. of Physics
10. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States). Berkeley Center for Cosmological Physics; Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France). Inst. de Biologie et Technologies de Saclay et CNRS
11. Centre National de la Recherche Scientifique (CNRS), Paris (France). Inst. d'Astrophysique de Paris; Scuola Internazionale di Studi Superiori Avanzati (SISSA), Trieste (Italy); Istituto Nazionale di Fisica Nucleare (INFN) Sezione di Trieste (Italy)
12. Univ. degli Studi di Padova (Italy). Dipartimento di Fisica e Astronomia "G. Galilei"; Istituto Nazionale di Fisica Nucleare (INFN), Padova (Italy); Istituto Nazionale di Astrofisica (INAF), Padova (Italy). Osservatorio Astronomico di Padova
13. Centre National de la Recherche Scientifique (CNRS), Paris (France). Inst. d'Astrophysique de Paris; Univ. of Birmingham (United Kingdom). Inst. for Gravitational Wave Astronomy and School of Physics and Astronomy
14. Univ. degli Studi di Padova (Italy). Dipartimento di Fisica e Astronomia "G. Galilei"; Istituto Nazionale di Fisica Nucleare (INFN), Padova (Italy); Istituto Nazionale di Astrofisica (INAF), Padova (Italy). Osservatorio Astronomico di Padova; Gran Sasso Science Inst., L'Aquila (Italy)
15. King's College London (United Kingdom). Theoretical Particle Physics and Cosmology Group; Univ. of London (United Kingdom). Physics Dept.

Publication Date:

2019-07-15

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1567164

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Cosmology and Astroparticle Physics

Additional Journal Information:

Journal Volume: 2019; Journal Issue: 07; Journal ID: ISSN 1475-7516

Publisher:

Institute of Physics (IOP)

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS