An excess of small-scale gravitational lenses observed in galaxy clusters

Meneghetti, M.; Davoli, Guido; Bergamini, P.; Rosati, P.; Natarajan, Priyamvada; Giocoli, Carlo; Caminha, G. B.; Metcalf, R. Benton; Rasia, Elena; Borgani, S.; Calura, F.; Grillo, C.; Mercurio, A.; Vanzella, E.

doi:10.1126/science.aax5164

Cited by 155 publications

(133 citation statements)

References 104 publications

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“…Image reproduced with permission from Okabe and Smith (2016), copyright by the authors are currently limited to a relatively small number of high-mass clusters with deep multiwavelength observations (see Sereno et al 2018b;Umetsu et al 2018). These results are all in support of the standard explanation for dark matter as effectively collisionless and nonrelativistic on sub-megaparsec scales and beyond, with an excellent match with standard KCDM predictions (however, see Meneghetti et al 2020, for an excess of galaxy-galaxy strong-lensing events in clusters with respect to KCDM).…”

Section: Cluster Mass Distributionsupporting

confidence: 63%

Cluster–galaxy weak lensing

Umetsu

2020

Astron Astrophys Rev

101

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Weak gravitational lensing of background galaxies provides a direct probe of the projected matter distribution in and around galaxy clusters. Here, we present a self-contained pedagogical review of cluster–galaxy weak lensing, covering a range of topics relevant to its cosmological and astrophysical applications. We begin by reviewing the theoretical foundations of gravitational lensing from first principles, with a special attention to the basics and advanced techniques of weak gravitational lensing. We summarize and discuss key findings from recent cluster–galaxy weak-lensing studies on both observational and theoretical grounds, with a focus on cluster mass profiles, the concentration–mass relation, the splashback radius, and implications from extensive mass-calibration efforts for cluster cosmology.

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Section: Cluster Mass Distributionsupporting

confidence: 63%

Cluster–galaxy weak lensing

Umetsu

2020

Astron Astrophys Rev

101

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“…This endorses the positive curvature of the early Universe with a confidence level greater than 99% (Aghanim et al, 2020;Di Valentino, Melchiorri and Silk, 2020). Besides, the gravitational lensing by substructures of several galaxy clusters is an order of magnitude more than the ΛCDM estimation (Meneghetti et al, 2020;Umetsu, 2020). This evidence endorses a spatially curved Universe in spite of the spacetime flatness of the local/present Universe.…”

Section: Introductionmentioning

confidence: 51%

Extended General Relativity for a Curved Universe

Al-Fadhli¹

2021

Preprint

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The recent Planck Legacy release revealed the presence of an enhanced lensing amplitude in the cosmic microwave background (CMB). Notably, this amplitude is higher than that estimated by the lambda cold dark matter model (ΛCDM), which endorses the positive curvature of the early Universe with a confidence level greater than 99%. Although General Relativity (GR) performs accurately in the local/present Universe where spacetime is almost flat, its lost boundary term, incompatibility with quantum mechanics and the necessity of dark matter and dark energy might indicate its incompleteness. By utilising the Einstein–Hilbert action, this study presents extended field equations considering the pre-existing/background curvature and the boundary contribution. The extended field equations consist of Einstein field equations with a conformal transformation feature in addition to the boundary term, which could remove singularities from the theory and facilitate its quantisation. The extended equations have been utilised to derive the evolution of the Universe with reference to the scale factor of the early Universe and its radius of curvature.

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“…Notably, it is more than that estimated by the lambda cold dark matter model (ΛCDM), which endorses the positive curvature of the early Universe with a confidence level more than 99% [5,6]. Besides, the observed gravitational lensing by substructures of several galaxy clusters is an order of magnitude higher than that estimated by the ΛCDM [7,8]. This endorses a curved Universe despite of the present/local space-time flatness.…”

Section: Introductionmentioning

confidence: 86%

On Spacetime Duality and Bounce Cosmology of a Dual Universe

Al-Fadhli¹

2021

Preprint

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The recent Planck Legacy release confirmed the existence of an enhanced lensing amplitude in the cosmic microwave background (CMB) power spectra, which endorses the positive curvature of the early Universe with a confidence level exceeding 99%. In this study, the pre-existing curvature is incorporated to extend the field equations where the derived wave function of the Universe is utilized to model Universe evolution with reference to the scale factor of the early Universe and its radius of curvature upon the emission of the CMB. The wave function reveals both positive and negative solutions, implying that matter and antimatter of early Universe plasma evolve in opposite directions as distinct Universe sides. The wave function indicates that a nascent hyperbolic expansion is followed by a first phase of decelerating expansion away from early plasma during the first 10 Gyr, and then, a second phase of accelerating expansion in reverse directions, whereby both Universe sides free-fall towards each other under gravitational acceleration. Simulations of the predicted conformal curvature evolution demonstrate the fast orbital speed of outer stars owing to the external fields exerted on galaxies as they travel through conformally curved space-time. Finally, the wave function predicts an eventual time-reversal phase comprising rapid spatial contraction that culminates in a Big Crunch, signalling a cyclic Universe. These findings reveal that early plasma could have separated and evolved into distinct sides that collectively and geometrically influencing the Universe evolution, physically explanting the effects attributed to dark matter and energy.

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An excess of small-scale gravitational lenses observed in galaxy clusters

Cited by 155 publications

References 104 publications

Cluster–galaxy weak lensing

Cluster–galaxy weak lensing

Extended General Relativity for a Curved Universe

On Spacetime Duality and Bounce Cosmology of a Dual Universe

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