Forecasts on the speed of gravitational waves at high z

Abstract

The observation of GW170817 binary neutron star (BNS) merger event has imposed strong bonds on the speed of gravitational waves (GWs) locally, inferring that the speed of GWs propagation is equal to the speed of light. Current GW detectors in operation will not be able to observe BNS merger to long cosmological distance, where possible cosmological corrections on the cosmic expansion history are expected to play an important role, specially for investigating possible deviations from general relativity. Future GW detectors designer projects will be able to detect many coalescences of BNS at high z, such as the third generation of the ground GW detector called Einstein Telescope (ET) and the space-based detector deci-hertz interferometer gravitational wave observatory (DECIGO). In this paper, we relax the condition cT /c = 1 to investigate modified GW propagation where the speed of GWs propagation is not necessarily equal to the speed of light. Also, we consider the possibility for the running of the Planck mass corrections on modified GW propagation. We parametrize both corrections in terms of an effective GW luminosity distance and we perform a forecast analysis using standard siren events from BNS mergers, within the sensitivity predicted for the ET and DECIGO. We find very strong constraints on the running of the Planck mass, namely O(10 −1 ) and O(10 −2 ) from ET and DECIGO, respectively. Possible anomalies on GW propagation are bound to |cT /c − 1| ≤ 10 −2 (10 −3 ) from ET (DECIGO). We finally discuss the consequences of our results on modified gravity phenomenology. PACS numbers: 98.80.-k, 95.36.+x, 04.50.Kd, 04.30.Nk arXiv:1910.05631v1 [gr-qc]

Gauss–Bonnet term corrections in scalar field cosmology

“…Nevertheless, in the paper [73] it was shown that condition |c g − 1| ≤ 5 × 10 −16 is met only for distances corresponding to redshift z < 0.1 and on large scales the constraint on the velocity of propagation of gravitational waves can changes. Taking into account the dependence from redshift, this constraint was estimated as follows…”

“…from z = 2 to the CMB scale (z ∼ 1100) [73]. Thus, one can consider the coupling function ξ which differ from (68) or (72) to analyze the models of cosmological inflation based on EGB gravity, tacking into account restriction (74) on the velocity of relic gravitational waves instead of extrapolation of constraint (66) to the inflationary stage of the evolution of the universe.…”

“…= − 2 = 4ξ 0 a GB (73). The conditions (68)-(70) and (72)-(73) significantly limit the possible models of cosmological inflation based on the Einstein-Gauss-Bonnet gravity.…”

Searching for modified gravity in the astrophysical gravitational wave background: Application to ground-based interferometers

“…Current detectors are not sensitive enough to probe the Universe at cosmological distances, not more than z ≲ 1. But, certainly, some promising projects like ET, CE and LISA will be able to detect GW events with great accuracy at cosmological distances and provide information for powerful cosmological tests [53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70].…”

Forecast constraints on anisotropic stress in dark energy using gravitational waves

“…Cai & Zhang 2016;Maselli et al 2016;Baker et al 2017;Bettoni et al 2017;Creminelli & Vernizzi 2017;Addazi, Cai & Marciano 2018;Cai et al 2018;Casalino et al 2018;Chakraborty et al 2018;Flauger & Weinberg 2018;Liu et al 2018;Oost, Mukohyama & Wang 2018;Visinelli, Bolis & Vagnozzi 2018;Zhao, Wright & Li 2018). In the recent past, the effects of the GWSS data on various cosmological theories and related key parameters have been greatly studied and due to its growing interest in the cosmological community as reflected in a series of investigations performed by many investigators (Nunes, Pan & Saridakis 2018;Shafieloo, Keeley & Linder 2020;Wei 2018;Zhang et al 2018;Casalino et al 2019;Copeland et al 2019;Bonilla et al 2020;Belgacem et al 2019;D'Agostino & Nunes 2019;Kase & Tsujikawa 2019;Lin et al 2019;Nunes, Alves & de Araujo 2019;Qiao et al 2019;Zhao et al 2019a,b;Zhao et al 2020), it is clearly realized that GWSS are in the limelight of modern cosmology. Thus, the consideration of GWSS has significant effects on the dynamics of our universe.…”