GW170817 falsifies dark matter emulators

Boran, Sibel; Desai, S.; Kahya, E. O.; Woodard, R. P.

doi:10.1103/physrevd.97.041501

Cited by 179 publications

(158 citation statements)

References 85 publications

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“…By the end of the O2 observing run in August 2017, the LIGO/Virgo detectors had observed ten binary black hole mergers and a single binary neutron star inspiral [2]. This handful of observations has already had a profound impact on our understanding of the astrophysics of compact objects and ruled out a number of modified theories of gravity [3][4][5][6][7]. During the ongoing O3 observing run new events are being reported at the rate of one per week, so these constraints are rapidly improving.…”

Section: Introductionmentioning

confidence: 99%

Transition from inspiral to plunge: A complete near-extremal trajectory and associated waveform

2020

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We extend the Ori and Thorne (OT) procedure to compute the transition from an adiabatic inspiral into a geodesic plunge for any spin. Our analysis revisits the validity of the approximations made in OT. In particular, we discuss possible effects coming from eccentricity and non-geodesic past-history of the orbital evolution. We find three different scaling regimes according to whether the mass ratio is much smaller, of the same order or much larger than the near extremal parameter describing how fast the primary black hole rotates. Eccentricity and non-geodesic past-history corrections are always sub-leading, indicating that the quasi-circular approximation applies throughout the transition regime. However, we show that the OT assumption that the energy and angular momentum evolve linearly with proper time must be modified in the near-extremal regime. Using our transition equations, we describe an algorithm to compute the full worldline in proper time for an extreme mass ratio inspiral (EMRI) and the full gravitational waveform in the high spin limit.

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Section: Introductionmentioning

confidence: 99%

Transition from inspiral to plunge: A complete near-extremal trajectory and associated waveform

2020

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“…In particular, this test has an impact on Einstein-Aether theories [25], including some sectors of Hořava gravity [55], and more general frameworks such as Generarlized Proca theories [56]. TeVeS [27] and MOND-like theories [57,58] are as well critically affected by this bound. Massive gravity [24], bigravity [59] and multi-gravity [60] remain viable as long as the graviton mass is small and matter couples minimally to one of the metrics.…”

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confidence: 99%

Dark Energy After GW170817: Dead Ends and the Road Ahead

2017

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Multi-messenger gravitational wave (GW) astronomy has commenced with the detection of the binary neutron star merger GW170817 and its associated electromagnetic counterparts. The almost coincident observation of both signals places an exquisite bound on the GW speed |cg/c − 1| ≤ 5 · 10 −16 . We use this result to probe the nature of dark energy (DE), showing that a large class of scalar-tensor theories and DE models are highly disfavored. As an example we consider the covariant Galileon, a cosmologically viable, well motivated gravity theory which predicts a variable GW speed at low redshift. Our results eliminate any late-universe application of these models, as well as their Horndeski and most of their beyond Horndeski generalizations. Three alternatives (and their combinations) emerge as the only possible scalar-tensor DE models: 1) restricting Horndeski's action to its simplest terms, 2) applying a conformal transformation which preserves the causal structure and 3) compensating the different terms that modify the GW speed (to be robust, the compensation has to be independent on the background on which GWs propagate). Our conclusions extend to any other gravity theory predicting varying cg such as Einstein-Aether, Hořava gravity, Generalized Proca, TeVeS and other MOND-like gravities. [6]. In this letter we present the implications that this measurement has for the nature of dark energy (DE) and tests of General Relativity (GR).The present cosmic acceleration is probably one of the greatest challenges in modern physics. Leaving the theoretical fine tuning issues aside [7], a cosmological constant is the leading candidate to explain this acceleration since it is fully consistent with observations [8]. Alternative scenarios that explain DE dynamically require either additional degrees of freedom (beyond the massless spin-2 field of GR) or a low-energy violation of fundamental principles such as locality [9]. The extremely low energy scale for DE requires additional degrees of freedom to be hidden on small scales by a screening mechanism [10], which also suppresses their rate of emission as additional gravitational wave polarizations [11].New fields coupled to gravity can affect the propagation speed of the standard GW polarizations, as measured by GW170817 and its counterparts [12]. Anomalous GW speed can be used to test even screened theories, as signals from extra-galactic sources probe unscreened, cosmological scales. In addition, effects on GW propagation accumulate over the travel time of the signals, amplifying their magnitude and yielding an impressive sensitivity. GW astronomy is therefore the most powerful tool to test models that modify GW propagation.Some of the most interesting dark energy models predict an anomalous GW speed and are ruled out by GW170817. These include cosmologically viable, screened and self-accelerating models like the covariant Galileon [13,14], or proposals to solve the cosmological constant problem like the Fab-four [15]. We will describe the implications of GW170817 on thes...

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“…The recent first direct measurements of gravitational waves (GWs), inaugurated with GW150914 [48] emitted by a black hole merger, have opened a new frontier for observational astrophysics and cosmology [49]. In particular, the gravitational wave event GW170817 [41] from a neutron star merger with its electromagnetic counterpart GRB170817A [50] has provided strong constraints on the possible physics of the dark sector [38,39,51,52,53,54,55,56,57]. GWs can also be used to measure a variation of the Planck mass [38,58,59,60,61,62] and test the late-time cosmology [63,64,65] through Standard Sirens [66,67].…”

Section: Tensor Perturbationsmentioning

confidence: 99%

Dark degeneracy I: Dynamical or interacting dark energy?

Marttens

Lombriser

Kunz

et al. 2020

Physics of the Dark Universe

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A R T I C L E I N F OKeywords: cosmology dark energy bayesian inference A B S T R A C TWe revisit the dark degeneracy that arises from the Einstein equations relating geometry to the total cosmic substratum but not resolving its individual components separately. We establish the explicit conditions for the dark degeneracy in the fluid description of the dark sector. At the background level, this degeneracy can be formally understood in terms of a unified dark sector Equation of State (EoS) that depends both on the dynamical nature of the dark energy (DE) as well as on its interaction with the pressureless dark matter. For linear perturbations, the degeneracy arises for specified DE pressure perturbations (or sound speed, equivalently) and DE anisotropic stress. Specializing to the degeneracy between non-interacting dynamical DE and interacting vacuum DE models, we perform a parameter estimation analysis for a range of dynamical DE parametrizations, where for illustration we explicitly break the degeneracy at the linear level by adopting a luminal sound speed for both scenarios. We conduct this analysis using cosmological background data alone and in combination with Planck measurements of the cosmic microwave background radiation. We find that although the overall phenomenology between the dynamical DE and interacting approaches is similar, there are some intriguing differences. In particular, there is an ambiguity in the strength of constraints on Ω 0 and 8 , which are considerably weakened for interacting vacuum DE, indicating that the dark degeneracy can change the significance of tensions in cosmological parameters inferred from different data sets. ( Jailson Alcaniz) ORCID(s): Rodrigo von Marttens et al.: Preprint submitted to Elsevier

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GW170817 falsifies dark matter emulators

Cited by 179 publications

References 85 publications

Transition from inspiral to plunge: A complete near-extremal trajectory and associated waveform

Transition from inspiral to plunge: A complete near-extremal trajectory and associated waveform

Dark Energy After GW170817: Dead Ends and the Road Ahead

Dark degeneracy I: Dynamical or interacting dark energy?

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