Probing cosmic anisotropy with gravitational waves as standard sirens

Abstract

The gravitational wave (GW) as a standard siren directly determines the luminosity distance from the gravitational waveform without reference to the specific cosmological model, of which the redshift can be obtained separately by means of the electromagnetic counterpart like GW events from binary neutron stars and massive black hole binaries (MBHBs). To see to what extent the standard siren can reproduce the presumed dipole anisotropy written in the simulated data of standard siren events from typical configurations of GW detectors, we find that (1) for the Laser Interferometer Space Antenna with different MBHB models during five-year observations, the cosmic isotropy can be ruled out at 3σ confidence level (C.L.) and the dipole direction can be constrained roughly around 20% at 2σ C.L., as long as the dipole amplitude is larger than 0.03, 0.06 and 0.025 for MBHB models Q3d, pop III and Q3nod with increasing constraining ability, respectively; (2) for Einstein Telescope with no less than 200 standard siren events, the cosmic isotropy can be ruled out at 3σ C.L. if the dipole amplitude is larger than 0.06, and the dipole direction can be constrained within 20% at 3σ C.L. if the dipole amplitude is near 0.1; (3) for the Deci-Hertz Interferometer Gravitational wave Observatory with no less than 100 standard siren events, the cosmic isotropy can be ruled out at 3σ C.L. for dipole amplitude larger than 0.03 , and the dipole direction can even be constrained within 10% at 3σ C.L. if the dipole amplitude is larger than 0.07. Our work manifests the promising perspective of the constraint ability on the cosmic anisotropy from the standard siren approach.

Listening to the sound of dark sector interactions with gravitational wave standard sirens

“…The ratio of number of events for the former versus the latter is taken to be 0.03, with mass distributions specified in [166]. Following [166,188,189,190,191], we then model the merger rate of the sources R(z), and from their merger rate we are able to determine their redshift distribution P (z) (see [166] for detailed formulas). Once we have P (z), we sample 1000 values of redshifts from this distribution: these will be the redshifts of our mock GW events z i .…”

Probing cosmic anisotropy with GW/FRB as upgraded standard sirens

“…F +,× are the antenna pattern functions for the two polarizations h +,× , (θ, φ) are the directional angles of the source in the detector frame, and ψ is the polarization angle. Note that, one can take ι = 0 • as argued in [5] and references therein. On the other hand, the dispersion measure is defined as the observed column density of the free electrons along the line-of-sight [25,26,38,39],…”

“…for givenã(f ) andb(f ) as the Fourier transforms of some functions a(t) and b(t), and S h (f ) denotes the one-side noise power spectral density (PSD) characterizing the performance of GW detector. The noise PSD for ET is [5,46]. from the Planck 2015 data [48].…”

“…The luminosity distance can be directly determined from the gravitational waveform of coalescing binaries and the redshift can be inferred from the associated electromagnetic (EM) counterpart. In a previous work [5], we have demonstrated the promiseful perspective of constraint ability on cosmic anisotropy using gravitational wave (GW) as standard siren. We found that with a few hundreds standard siren events, the cosmic isotropy can be ruled out at 3σ confidence level (C.L.)…”

Future constraints on dynamical dark-energy using gravitational-wave standard sirens

“…Here, considering these four well known dark energy parametrzations, namely, CPL, Logarithmic, JBP and BA, we perform a robust analysis by constraining their parameter space using the simulated GW data from the Einstein Telescope along with the standard astronomical probes such as cosmic microwave background radiation (CMB) [49,50], baryon acoustic oscillations (BAO) [51][52][53], Supernove Type Ia (SNIa) [54] and Hubble parameter measurements from the cosmic chronometers (CC) [55], in order to see how the data from GW improve the parameter space of these known parametrizations compared to their usual cosmological constraints availed from the known cosmological probes, CMB, BAO, SNIa and CC. We refer to some earlier works on dark energy with similar motivation, that means where the simulated GW data from the Einstein Telescope were taken into account [56][57][58][59][60][61]. We mention that it will be also interesting to use simulated GW data from other observatories like Laser Interferometer Space Antenna (LISA) [70], Deci-hertz Interferometer Gravitational wave Observatory (DECIGO) [71,72], TianQin [73].…”