Found 923 results, showing the newest relevant preprints. Sort by relevancy only.Update me on new preprints

Probing the cosmic opacity from Future **Gravitational** **Wave** Standard
Sirens

In this work, using the Gaussian Process, we explore the potentiality of future gravitational wave (GW) measurement to probe cosmic opacity through comparing its opacity-free luminosity distance (LD) with the opacity-dependent one from type Ia supernovae (SNIa). Expand abstract.

In this work, using the Gaussian Process, we explore the potentiality of future

**gravitational****wave**(GW) measurement to probe cosmic opacity through comparing its opacity-free luminosity distance (LD) with the opacity-dependent one from type Ia supernovae (SNIa). GW data points are simulated from the third generation Einstein Telescope, and SNIa data are taken from the Joint Light Analysis (JLA) or Pantheon compilation. The advantages of using Gaussian Process are that one may match SNIa data with GW data at the same redshift and use all available data to probe cosmic opacity. We obtain that the error bar of the constraint on cosmic opacity can be reduced to $\sigma_{\epsilon}\sim 0.011$ and $0.006$ at $1\sigma$ confidence level (CL) for JLA and Pantheon respectively in a cosmological-independent way. Thus, the future GW measurements can give competitive results on the cosmic opacity test. Furthermore, we propose a method to probe the spatial homogeneity of the cosmic transparency through comparing the reconstructed LD from the mock GW with the reconstructed one from SNIa data in a flat $\Lambda$CDM with the Gaussian Process. The result shows that a transparent universe is favored at $1\sigma$ CL, although the best-fit value of cosmic opacity is redshift-dependent.44 days ago

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arXiv

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arXiv

Beyond the Standard Models with Cosmic Strings

We consider the impact of particle production on the

**gravitational**-**wave**emission by loops. Expand abstract. We examine which information on the early cosmological history can be extracted from the potential measurement by third-generation

**gravitational**-**wave**observatories of a stochastic**gravitational****wave**background (SGWB) produced by cosmic strings. We consider a variety of cosmological scenarios breaking the scale-invariant properties of the spectrum, such as early long matter or kination eras, short intermediate matter and inflation periods inside a radiation era, and their specific signatures on the SGWB. This requires to go beyond the usually-assumed scaling regime, to take into account the transient effects during the change of equation of state of the universe. We compute the time evolution of the string network parameters and thus the loop-production efficiency during the transient regime, and derive the corresponding shift in the turning-point frequency. We consider the impact of particle production on the**gravitational**-**wave**emission by loops. We estimate the reach of future interferometers LISA, BBO, DECIGO, ET and CE and radio telescope SKA to probe the new physics energy scale at which the universe has experienced changes in its expansion history. We find that a given interferometer may be sensitive to very different energy scales, depending on the nature and duration of the non-standard era, and the value of the string tension. It is fascinating that by exploiting the data from different GW observatories associated with distinct frequency bands, we may be able to reconstruct the full spectrum and therefore extract the values of fundamental physics parameters.44 days ago

4/10 relevant

arXiv

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arXiv

**Gravitational** **Waves** in Scalar-Tensor-Vector Gravity Theory

The polarizations of the

**gravitational****waves**are investigated by analyzing the relative motion of the test particles. Expand abstract. In this paper, we study the properties of

**gravitational****waves**in the scalar-tensor-vector gravity theory. The polarizations of the**gravitational****waves**are investigated by analyzing the relative motion of the test particles. It is found that the interaction between the matter and vector field in the theory leads to two additional transverse polarization modes. By making use of the polarization content, the stress-energy pseudo-tensor is calculated by employing the perturbed equation method. Besides, the relaxed field equation for the modified gravity in question is derived by using the Landau-Lifshitz formalism suitable to systems with non-negligible self-gravity.45 days ago

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arXiv

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arXiv

Gaussian processes reconstruction of modified **gravitational** **wave**
propagation

Recent work has shown that modified gravitational wave (GW) propagation can be a powerful probe of dark energy and modified gravity, specific to GW observations. Expand abstract.

Recent work has shown that modified

**gravitational****wave**(GW) propagation can be a powerful probe of dark energy and modified gravity, specific to GW observations. We use the technique of Gaussian processes, that allows the reconstruction of a function from the data without assuming any parametrization, to measurements of the GW luminosity distance from simulated joint GW-GRB detections, combined with measurements of the electromagnetic luminosity distance by simulated DES data. For the GW events we consider both a second-generation LIGO/Virgo/Kagra (HVLKI) network, and a third-generation detector such as the Einstein Telescope. We find that the HVLKI network at target sensitivity, with $O(15)$ neutron star binaries with electromagnetic counterpart, could already detect deviations from GR at a level predicted by some modified gravity models, and a third-generation detector such as ET would have a remarkable discovery potential. We discuss the complementarity of the Gaussian processes technique to the $(\Xi_0,n)$ parametrization of modified GW propagation.52 days ago

7/10 relevant

arXiv

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arXiv

High accuracy on $H_0$ constraints from **gravitational** **wave** lensing
events

In light of the newly opened and rapidly growing GW window in multi-messenger astronomy, in order to fully take advantage of the new opportunities we are provided with, new ideas are required for a better and deeper employ of the state-of-the-art probes we handle. Expand abstract.

In light of the newly opened and rapidly growing GW window in multi-messenger astronomy, in order to fully take advantage of the new opportunities we are provided with, new ideas are required for a better and deeper employ of the state-of-the-art probes we handle. Following this goal, here we suggest a method to constrain the cosmological background, and the Hubble constant in particular, by future observations of gravitationally lensed radiation emitted by a single source in both the

**gravitational****wave**and the electromagnetic regimes. The lensing of the**gravitational****wave**radiation, in fact, can leave a clear imprinting in the corresponding waveform, and we want to analyze if such kind of measurements can be successfully employed to better constrain the cosmological background. Thus, by making use of**wave**optics for the**gravitational****wave**lensed signal, and of standard geometrical optics approximation for the electromagnetic one, we study the impact of different cosmological parameters on the value of the arrival time delay due to**gravitational**lensing, given specific GW frequencies, mass models of the lens, and redshifts and positions (with respect to the lens) of the source. Although the rate of lensing of**gravitational****waves**is expected to be low, we show that even one single event could provide us with an uncertainty on $H_0$ comparable with present independent probes in a "pessimistic" scenario (with a pulsar population similar to present Pulsar Timing Array state), and of two orders smaller in an optimistic one (with a number of observed pulsars as large as that expected from the Square Kilometer Array). Thus, its role in the solution of the Hubble tension could be decisive.52 days ago

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arXiv

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arXiv

AION: An Atom Interferometer Observatory and Network

We outline the experimental concept and key scientific capabilities of AION (Atom Interferometer Observatory and Network), a proposed UK-based experimental programme using cold strontium atoms to search for ultra-light dark matter, to explore

**gravitational****waves**in the mid-frequency range between the peak sensitivities... Expand abstract. We outline the experimental concept and key scientific capabilities of AION (Atom Interferometer Observatory and Network), a proposed UK-based experimental programme using cold strontium atoms to search for ultra-light dark matter, to explore

**gravitational****waves**in the mid-frequency range between the peak sensitivities of the LISA and LIGO/Virgo/ KAGRA/INDIGO/Einstein Telescope/Cosmic Explorer experiments, and to probe other frontiers in fundamental physics. AION would complement other planned searches for dark matter, as well as probe mergers involving intermediate mass black holes and explore early universe cosmology. AION would share many technical features with the MAGIS experimental programme in the US, and synergies would flow from operating AION in a network with this experiment, as well as with other atom interferometer experiments such as MIGA, ZAIGA and ELGAR. Operating AION in a network with other**gravitational****wave**detectors such as LIGO, Virgo and LISA would also offer many synergies.52 days ago

6/10 relevant

arXiv

6/10 relevant

arXiv

**Gravitational** **Waves** from Hierarchical Triple Systems with Kozai-Lidov
Oscillation

We study

**gravitational****waves**from a hierarchical three-body system up to first-order postNewtonian approximation. Expand abstract. We study

**gravitational****waves**from a hierarchical three-body system up to first-order postNewtonian approximation. Under certain conditions, the existence of a nearby third body can cause periodic exchange between eccentricity of an inner binary and relative inclination, known as Kozai-Lidov oscillations. We analyze features of the waveform from the inner binary system undergoing such oscillations. We find that variation caused due to the tertiary companion can be observed in the**gravitational**waveforms and energy spectra, which should be compared with those from isolated binaries and coplanar three-body system. The detections from future space interferometers will make possible the investigation of the**gravitational****wave**spectrum in mHz range and may fetch signals by sources addressed.53 days ago

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arXiv

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arXiv

Astrometric Effects of **Gravitational** **Wave** Backgrounds with non-Luminal
Propagation Speeds

These correlations are quantified and investigated for backgrounds of

**gravitational****waves**with sub- and super-luminal group velocities. Expand abstract. A passing

**gravitational****wave**causes a deflection in the apparent astrometric positions of distant stars. The effect of the speed of the**gravitational****wave**on this astrometric shift is discussed. A stochastic background of**gravitational****waves**would result in a pattern of astrometric deflections which are correlated on large angular scales. These correlations are quantified and investigated for backgrounds of**gravitational****waves**with sub- and super-luminal group velocities. The statistical properties of the correlations are depicted in two equivalent and related ways: as correlation curves and as angular power spectra. Sub-(super-)luminal**gravitational****wave**backgrounds have the effect of enhancing (suppressing) the power in low-order angular modes. Analytical representations of the redshift-redshift and redshift-astrometry correlations are also derived. The potential for using this effect for constraining the speed of gravity is discussed.55 days ago

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arXiv

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arXiv

Impact of polarised extragalactic sources on the measurement of CMB B-mode anisotropies

One of the main goals of Cosmology is to search for the imprint of primordial

**gravitational****waves**in the CMB polarisation field, to probe inflationary theories. Expand abstract. One of the main goals of Cosmology is to search for the imprint of primordial

**gravitational****waves**in the CMB polarisation field, to probe inflationary theories. One of the obstacles toward the detection of the primordial signal is to extract the B-mode polarisation from astrophysical contaminations. We present a complete analysis of extragalactic foreground contamination due to polarised emission of radio and dusty star-forming galaxies. We update or use up-to-date models that are validated using the most recent measurements. We predict the flux limit (confusion noise) for the future CMB space or balloon experiments (IDS, PIPER, SPIDER, LiteBIRD, PICO), as well as ground-based experiments (C-BASS, NEXT-BASS, QUIJOTE, AdvACTPOL, BICEP3+Keck, BICEPArray, CLASS, SO, SPT3G, S4). Telescope aperture size (and frequency) is the main characteristic impacting the level of confusion noise. Using the flux limits and assuming constant polarisation fractions for radio and dusty galaxies, we compute the B-mode power spectra of the three extragalactic foregrounds (radio source shot noise, dusty galaxy shot noise and clustering), discuss their relative levels and compare their amplitudes to that of the primordial tensor modes parametrized by the tensor-to-scalar ratio r. At the reionization bump (l=5), contamination by extragalactic foregrounds is negligible. At the recombination peak (l=80), while the contamination is much lower than the targeted sensitivity on r for large-aperture telescopes, it is at comparable level for some of the medium- and small-aperture telescope experiments. For example, the contamination is at the level of the 68 per cent confidence level uncertainty on the primordial r for the LiteBIRD and PICO space experiments. Finally we also provide some useful unit conversion factors and give some predictions for the SPICA B-BOP experiment. Abridged57 days ago

4/10 relevant

arXiv

4/10 relevant

arXiv

Multi-messenger astronomy with very-high-energy gamma-ray observations

After decades of development, multi-messenger astronomy, the combination of information on cosmic sources from photons, neutrinos, charged particles and

**gravitational****waves**, is now an established reality. Expand abstract. After decades of development, multi-messenger astronomy, the combination of information on cosmic sources from photons, neutrinos, charged particles and

**gravitational**waves, is now an established reality. Within this emerging discipline we argue that very-high-energy (VHE) gamma-ray observations play a special role. We discuss the recent progress on explosive transients, the connections between neutrino and gamma-ray astronomy and the search for search for dark matter. Finally, the experimental prospects for the next decade in the VHE gamma-ray field are summarised.64 days ago

4/10 relevant

arXiv

4/10 relevant

arXiv