Probing the Anisotropic Universe with Gravitational Waves

Colgáin, Eoin Ó

doi:10.48550/arxiv.2203.03956

Cited by 5 publications

(5 citation statements)

References 71 publications

(118 reference statements)

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“…It has also been shown that the large-scale distribution of galaxies in the Universe is not random [171], and it could have a preferred direction [66,71,73,77,[172][173][174][175][176][177]. These probes might not agree with the standard models [151,153,161,[178][179][180][181][182][183].…”

Section: Large-scale Structure Explanationmentioning

confidence: 99%

Asymmetry between Galaxy Apparent Magnitudes Shows a Possible Tension between Physical Properties of Galaxies and Their Rotational Velocity

McAdam

Shamir

2023

Symmetry

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Despite over a century of research, the physics of galaxy rotation is not yet fully understood, and there is a clear discrepancy between the observed mass of galaxies and their rotational velocity. Here, we report on another observation of tension between the physical properties of galaxies and their rotational velocity. We compare the apparent magnitude of galaxies and find a statistically significant asymmetry between galaxies that rotate in the same direction relative to the Milky Way and galaxies that rotate in the opposite direction relative to the Milky Way. While asymmetry in the brightness is expected due to the Doppler shift effect, such asymmetry is expected to be subtle. The observations shown here suggest that the magnitude difference is sufficiently large to be detected by Earth-based telescopes. The asymmetry is consistent in both the northern and southern galactic poles. The difference is also consistent across several different instruments such as DECam, SDSS, Pan-STARRS, and HST as well as different annotation methods, which include automatic, manual, or crowdsourcing annotations through “Galaxy Zoo”. The observation can also explain other anomalies such as the Ho tension. Analysis of Ia supernovae where the host galaxies rotate in the same direction relative to the Milky Way shows a much smaller tension with the Ho value as estimated by the CMB.

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Section: Large-scale Structure Explanationmentioning

confidence: 99%

Asymmetry between Galaxy Apparent Magnitudes Shows a Possible Tension between Physical Properties of Galaxies and Their Rotational Velocity

McAdam

Shamir

2023

Symmetry

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“…Last but not least, in principle also the AGWB is affected by the presence of a modulation of the gravitational potentials opening another window on the exploration of this anomaly. On the same line of reasoning, we could also investigate possible connections with large-scale structures and tracers [64,65]. We leave this for future exploration.…”

Section: Jcap09(2022)046mentioning

confidence: 94%

Test of the statistical isotropy of the universe using gravitational waves

Giacomo

Bartolo

Matarrese

et al. 2022

J. Cosmol. Astropart. Phys.

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Since WMAP and Planck some anomalous features appeared in the Cosmic Microwave Background (CMB) large-angle anisotropy, the so-called anomalies. One of these is the hemispherical power asymmetry, i.e. a difference in the average power on the two hemispheres centered around (l,b) = (221, -20), which shows a relatively high level of significance. Such an anomaly could be the signature of a departure from statistical isotropy on large scales. Here we investigate the physical origin of this anomaly using the Cosmological Gravitational Wave Background (CGWB) detectable by future GW detectors. Indeed, the CGWB offers a unique window to explore the early universe and we show that it can be used in combination with CMB data to shed light on the statistical isotropy of our universe. Specifically, we study the evolution of gravitons in the presence of a modulating field in the scalar gravitational potentials accounting for the hemispherical power asymmetry and we infer the amplitude of this modulating field through a minimal variance estimator exploiting both constrained and unconstrained realizations of the CGWB. We show that the addition of the CGWB will allow an improvement in the assessment of the physical origin of the CMB power asymmetry. Accounting for the expected performances of LISA and BBO, we also show that the latter is expected to be signal-dominated on large-scales, proving that the CGWB could be the keystone to assess the significance of this anomaly.

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“…As a promising cosmological probe, gravitational-wave (GW) standard sirens will play a crucial role in exploring the expansion history of the Universe; see, e.g., Dalal et al (2006), Cutler & Holz (2009), Zhao et al (2011Zhao et al ( , 2020, Cai & Yang (2017, 2018, Cai et al (2018aCai et al ( , 2018b, Chang et al (2019), Du et al (2019), He (2019), Yang et al (2019Yang et al ( , 2020, Zhang (2019), Bachega et al (2020), Borhanian et al (2020), Chen (2020), Gray et al (2020), Jin et al (2020Jin et al ( , 2021Jin et al ( , 2022Jin et al ( , 2023aJin et al ( , 2023bJin et al ( , 2023cJin et al ( , 2024, Chen et al (2021), Mitra et al (2021), Qi et al (2021), Ye & Fishbach (2021), Cao et al (2022), Colgáin (2022), de Souza et al (2022, Dhani et al (2022), Wang et al (2022aWang et al ( , 2022bWang et al ( , 2022d, Zhu et al (2022), Califano et al (2023), Han et al (2023), Hou et al (2023, Wu et al (2023), Zhang et al (2023), andSong et al (2...…”

Section: Introductionmentioning

confidence: 99%

Prospects for Probing the Interaction between Dark Energy and Dark Matter Using Gravitational-wave Dark Sirens with Neutron Star Tidal Deformation

Li,

Jin,

et al. 2024

ApJ

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Gravitational wave (GW) standard siren observations provide a rather useful tool to explore the evolution of the Universe. In this work, we wish to investigate whether dark sirens with neutron star (NS) deformation from third-generation GW detectors could help probe the interaction between dark energy and dark matter. We simulate the GW dark sirens of four detection strategies based on 3 yr observation and consider four phenomenological interacting dark energy (IDE) models to perform cosmological analysis. We find that GW dark sirens could provide tight constraints on Ωm and H 0 in the four IDE models but do not perform well in constraining the dimensionless coupling parameter β in models of the interaction proportional to the energy density of cold dark matter. Nevertheless, the parameter degeneracy orientations of cosmic microwave background (CMB) and GW are almost orthogonal, and thus, the combination of them could effectively break cosmological parameter degeneracies, with the constraint errors of β being 0.00068–0.018. In addition, we choose three typical equations of state (EoSs) of an NS, i.e., SLy, MPA1, and MS1, to investigate the effect of an NS’s EoS on cosmological analysis. The stiffer EoS could give tighter constraints than the softer EoS. Nonetheless, the combination of CMB and GW dark sirens (using different EoSs of an NS) shows basically the same constraint results of cosmological parameters. We conclude that the dark sirens from 3G GW detectors would play a crucial role in helping probe the interaction between dark energy and dark matter, and the CMB+GW results are basically not affected by the EoS of an NS.

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Probing the Anisotropic Universe with Gravitational Waves

Cited by 5 publications

References 71 publications

Asymmetry between Galaxy Apparent Magnitudes Shows a Possible Tension between Physical Properties of Galaxies and Their Rotational Velocity

Asymmetry between Galaxy Apparent Magnitudes Shows a Possible Tension between Physical Properties of Galaxies and Their Rotational Velocity

Test of the statistical isotropy of the universe using gravitational waves

Prospects for Probing the Interaction between Dark Energy and Dark Matter Using Gravitational-wave Dark Sirens with Neutron Star Tidal Deformation

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