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Articles de revues sur le sujet « Cosmic microwave background anomalies »

Auteur : Grafiati

Publié le 7 juin 2025

Mis à jour le 2 août 2025

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1

Axelsson, Magnus, Frode Hansen, Tomi Koivisto, and David F. Mota. "Cosmic microwave background anomalies from imperfect dark energy." Astronomy & Astrophysics 564 (April 2014): A113. http://dx.doi.org/10.1051/0004-6361/201322051.

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Mikelsons, Gatis, Joseph Silk, and Joe Zuntz. "Cosmic microwave background anomalies viewed via Gumbel statistics." Monthly Notices of the Royal Astronomical Society 400, no. 2 (2009): 898–902. http://dx.doi.org/10.1111/j.1365-2966.2009.15503.x.

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Land, K., and J. Magueijo. "Template fitting and the large-angle cosmic microwave background anomalies." Monthly Notices of the Royal Astronomical Society 367, no. 4 (2006): 1714–20. http://dx.doi.org/10.1111/j.1365-2966.2006.10078.x.

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Hansen, F. K., T. Trombetti, N. Bartolo, et al. "Isotropic non-Gaussian gNL-like toy models that reproduce cosmic microwave background anomalies." Astronomy & Astrophysics 626 (June 2019): A13. http://dx.doi.org/10.1051/0004-6361/201833698.

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Context. Based on recent observations of the cosmic microwave background (CMB), claims of statistical anomalies in the properties of the CMB fluctuations have been made. Although the statistical significance of the anomalies remains only at the ∼2−3σ significance level, the fact that there are many different anomalies, several of which support a possible deviation from statistical isotropy, has motivated a search for models that provide a common mechanism to generate them. Aims. The goal of this paper is to investigate whether these anomalies could originate from non-Gaussian cosmological mode

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Shi, Rui, Tobias A. Marriage, John W. Appel, et al. "Testing Cosmic Microwave Background Anomalies in E-mode Polarization with Current and Future Data." Astrophysical Journal 945, no. 1 (2023): 79. http://dx.doi.org/10.3847/1538-4357/acb339.

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Abstract In this paper, we explore the power of the cosmic microwave background (CMB) polarization (E-mode) data to corroborate four potential anomalies in CMB temperature data: the lack of large angular-scale correlations, the alignment of the quadrupole and octupole (Q–O), the point-parity asymmetry, and the hemispherical power asymmetry. We use CMB simulations with noise representative of three experiments—the Planck satellite, the Cosmology Large Angular Scale Surveyor (CLASS), and the LiteBIRD satellite—to test how current and future data constrain the anomalies. We find the correlation c

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Abramo, L. Raul, and Thiago S. Pereira. "Testing Gaussianity, Homogeneity, and Isotropy with the Cosmic Microwave Background." Advances in Astronomy 2010 (2010): 1–25. http://dx.doi.org/10.1155/2010/378203.

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We review the basic hypotheses which motivate the statistical framework used to analyze the cosmic microwave background, and how that framework can be enlarged as we relax those hypotheses. In particular, we try to separate as much as possible the questions of gaussianity, homogeneity, and isotropy from each other. We focus both on isotropic estimators of nongaussianity as well as statistically anisotropic estimators of gaussianity, giving particular emphasis on their signatures and the enhanced “cosmic variances” that become increasingly important as our putative Universe becomes less symmetr

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Ríos, Carlos, Pedro Labraña, and Antonella Cid. "The Emergent Universe and the Anomalies in the Cosmic Microwave Background." Journal of Physics: Conference Series 720 (May 2016): 012008. http://dx.doi.org/10.1088/1742-6596/720/1/012008.

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Bennett, C. L., R. S. Hill, G. Hinshaw, et al. "SEVEN-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE ( WMAP ) OBSERVATIONS: ARE THERE COSMIC MICROWAVE BACKGROUND ANOMALIES?" Astrophysical Journal Supplement Series 192, no. 2 (2011): 17. http://dx.doi.org/10.1088/0067-0049/192/2/17.

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Bojowald, Martin. "Cosmic Tangle: Loop Quantum Cosmology and CMB Anomalies." Universe 7, no. 6 (2021): 186. http://dx.doi.org/10.3390/universe7060186.

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Loop quantum cosmology is a conflicted field in which exuberant claims of observability coexist with serious objections against the conceptual and physical viability of its current formulations. This contribution presents a non-technical case study of the recent claim that loop quantum cosmology might alleviate anomalies in the observations of the cosmic microwave background.

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Copi, Craig J., Dragan Huterer, Dominik J. Schwarz, and Glenn D. Starkman. "Large-Angle Anomalies in the CMB." Advances in Astronomy 2010 (2010): 1–17. http://dx.doi.org/10.1155/2010/847541.

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We review the recently found large-scale anomalies in the maps of temperature anisotropies in the cosmic microwave background. These include alignments of the largest modes of CMB anisotropy with each other and with geometry and direction of motion of the solar ssystem, and the unusually low power at these largest scales. We discuss these findings in relation to expectation from standard inflationary cosmology, their statistical significance, the tools to study them, and the various attempts to explain them.

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Inoue, Kaiki Taro, and Joseph Silk. "Local Voids as the Origin of Large‐Angle Cosmic Microwave Background Anomalies. I." Astrophysical Journal 648, no. 1 (2006): 23–30. http://dx.doi.org/10.1086/505636.

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Polastri, L. "Cosmic Microwave Background large-scale directional anomalies as seen by Planck and WMAP." Journal of Physics: Conference Series 841 (May 2017): 012008. http://dx.doi.org/10.1088/1742-6596/841/1/012008.

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Samandar, Amirhossein, Javier Carrón Duque, Craig J. Copi, et al. "Cosmic topology. Part IIIa. Microwave background parity violation without parity-violating microphysics." Journal of Cosmology and Astroparticle Physics 2024, no. 11 (2024): 020. http://dx.doi.org/10.1088/1475-7516/2024/11/020.

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Abstract The standard cosmological model, which assumes statistical isotropy and parity invariance, predicts the absence of correlations between even-parity and odd-parity observables of the cosmic microwave background (CMB). Contrary to these predictions, large-angle CMB temperature anomalies generically involve correlations between even-ℓ and odd-ℓ angular power spectrum C ℓ , while recent analyses of CMB polarization have revealed non-zero equal-ℓ EB correlations. These findings challenge the conventional understanding, suggesting deviations from statistical isotropy, violations of parity,

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Pranav, Pratyush, Robert J. Adler, Thomas Buchert, et al. "Unexpected topology of the temperature fluctuations in the cosmic microwave background." Astronomy & Astrophysics 627 (July 2019): A163. http://dx.doi.org/10.1051/0004-6361/201834916.

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We study the topology generated by the temperature fluctuations of the cosmic microwave background (CMB) radiation, as quantified by the number of components and holes, formally given by the Betti numbers, in the growing excursion sets. We compare CMB maps observed by the Planck satellite with a thousand simulated maps generated according to the ΛCDM paradigm with Gaussian distributed fluctuations. The comparison is multi-scale, being performed on a sequence of degraded maps with mean pixel separation ranging from 0.05 to 7.33°. The survey of the CMB over 𝕊2 is incomplete due to obfuscation ef

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Roman, Soltero Alberto Rafael. "A Topological Model of the Universe: Klein Bottle and the Unification of the Big Crunch and Big Rip." Revista Multidisciplinaria de Ciencia Básica, Humanidades, Arte y Educación 2, no. 9 (2024): 24–32. https://doi.org/10.5281/zenodo.14184103.

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This paper presents a topological model of the universe based on the geometry of the Klein bottle, proposing that the Big Crunch and Big Rip may represent two manifestations of a single event within a non-orientable, cyclic universe. Using Roman’s Theorem of inverse permutations, which suggests symmetrical inverse states, the study explores how this topology may support a dynamic where cosmic expansion and collapse occur within a unified, cyclical framework. The model aims to reconcile certain anomalies observed in the Cosmic Microwave Background (CMB) and the distribution of dark matter

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RALSTON, JOHN P., and PANKAJ JAIN. "THE VIRGO ALIGNMENT PUZZLE IN PROPAGATION OF RADIATION ON COSMOLOGICAL SCALES." International Journal of Modern Physics D 13, no. 09 (2004): 1857–77. http://dx.doi.org/10.1142/s0218271804005948.

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We reconsider analysis of data on the cosmic microwave background on the largest angular scales. Temperature multipoles of any order factor naturally into a direct product of axial quantities and cosets. Striking coincidences exist among the axes associated with the dipole, quadrupole, and octupole CMB moments. These axes also coincide well with two other axes independently determined from polarizations at radio and optical frequencies propagating on cosmological scales. The five coincident axes indicate physical correlation and anisotropic properties of the cosmic medium not predicted by the

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Di Valentino, Eleonora Di. "Challenges of the Standard Cosmological Model." Universe 8, no. 8 (2022): 399. http://dx.doi.org/10.3390/universe8080399.

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Measurements of the temperature and polarization anisotropy of the cosmic microwave background (CMB) provided strong confirmation of the vanilla flat ΛCDM model of structure formation. Even if this model fits incredibly well, the cosmological and astrophysical observations in a wide range of scales and epochs, some interesting tensions between the cosmological probes, and anomalies in the CMB data, have emerged. These discrepancies have different statistical significance, and although some parts may be due to systematic errors, their persistence strongly indicates possible cracks in the standa

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Sha, Zhi Gang, and Rulin Xiu. "String Theory Explanation of Large-Scale Anisotropy and Anomalous Alignment." Reports in Advances of Physical Sciences 02, no. 01 (2018): 1750012. http://dx.doi.org/10.1142/s2424942417500128.

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The discovery of anomalies in the cosmic microwave background (CMB) indicates large-scale anisotropies, non-Gaussian distributions, and anomalous alignments of the quadrupole and octupole modes of the anisotropy with each other and with both the ecliptic and equinoxes. Further analysis indicates that the statistical anisotropy and non-Gaussian temperature fluctuations are mainly due to long-range correlations. However, the source of the large-scale correlation and the cause of the anomalous alignment in CMB remains unknown. In this work, we show a new development in string theory, the universa

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Rassat, A., J. L. Starck, and F. X. Dupé. "Removal of two large-scale cosmic microwave background anomalies after subtraction of the integrated Sachs-Wolfe effect." Astronomy & Astrophysics 557 (August 20, 2013): A32. http://dx.doi.org/10.1051/0004-6361/201219793.

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Francis, Caroline L., and John A. Peacock. "An estimate of the local integrated Sachs-Wolfe signal and its impact on cosmic microwave background anomalies." Monthly Notices of the Royal Astronomical Society 406, no. 1 (2010): 14–21. http://dx.doi.org/10.1111/j.1365-2966.2010.16866.x.

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21

Hogan, Craig, and Stephan S. Meyer. "Angular correlations of causally-coherent primordial quantum perturbations." Classical and Quantum Gravity 39, no. 5 (2022): 055004. http://dx.doi.org/10.1088/1361-6382/ac4829.

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Abstract We consider the hypothesis that nonlocal, omnidirectional, causally-coherent quantum entanglement of inflationary horizons may account for some well-known measured anomalies of cosmic microwave background (CMB) anisotropy on large angular scales. It is shown that causal coherence can lead to less cosmic variance in the large-angle power spectrum C ℓ of primordial curvature perturbations on spherical horizons than predicted by the standard model of locality in effective field theory, and to new symmetries of the angular correlation function C(Θ). Causal considerations are used to const

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Zhao, Wen, and Larissa Santos. "The Weird Side of the Universe: Preferred Axis." International Journal of Modern Physics: Conference Series 45 (January 2017): 1760009. http://dx.doi.org/10.1142/s2010194517600096.

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In both WMAP and Planck observations on the temperature anisotropy of cosmic microwave background (CMB) radiation a number of large-scale anomalies were discovered in the past years, including the CMB parity asymmetry in the low multipoles. By defining a directional statistics, we find that the CMB parity asymmetry is directional dependent, and the preferred axis is stable, which means that it is independent of the chosen CMB map, the definition of the statistic, or the CMB masks. Meanwhile, we find that this preferred axis strongly aligns with those of the CMB quadrupole, octopole, as well as

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Inoue, Kaiki Taro, and Joseph Silk. "Local Voids as the Origin of Large‐Angle Cosmic Microwave Background Anomalies: The Effect of a Cosmological Constant." Astrophysical Journal 664, no. 2 (2007): 650–59. http://dx.doi.org/10.1086/517603.

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Sánchez, Juan C. Bueno. "On the breaking of statistical isotropy through inflationary relics." Modern Physics Letters A 31, no. 21 (2016): 1640004. http://dx.doi.org/10.1142/s0217732316400046.

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We explore a mechanism to generate local contributions to the curvature perturbation in isolated patches of the cosmic microwave background (CMB). The mechanism, based on the generation of an out-of-equilibrium configuration of a fluctuating scalar field of mass m [Formula: see text]H during a sustained stage of fast-roll inflation, has been recently shown to be capable of accounting for some of the most robust large-angle anomalies detected in the CMB. In this paper, we show in detail how the embedding of the mechanism into models including vector fields can result in the breaking of statisti

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Selub, Nathaniel, Frederick Wehlen, Craig Hogan, and Stephan S. Meyer. "Anomalies of cosmic anisotropy from holographic universality of great-circle variance." Classical and Quantum Gravity 39, no. 7 (2022): 075016. http://dx.doi.org/10.1088/1361-6382/ac566d.

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Abstract We examine all-sky cosmic microwave background temperature maps on large angular scales to compare their consistency with two scenarios: the standard inflationary quantum picture, and a distribution constrained to have a universal variance of primordial curvature perturbations on great circles. The latter symmetry is not a property of standard quantum inflation, but may be a symmetry of holographic models with causal quantum coherence on null surfaces. Since the variation of great-circle variance is dominated by the largest angular scale modes, in the latter case the amplitude and dir

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Capistrano, Abraão J. S., Luís A. Cabral, Carlos H. Coimbra-Araújo, and José A. P. F. Marão. "On Low Hubble Expansion Rate from Planck Data Anomalies." Galaxies 10, no. 6 (2022): 118. http://dx.doi.org/10.3390/galaxies10060118.

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From the linear perturbations of Nash–Greene fluctuations of a background metric, we obtain profiles of Hubble function evolution H(z) and fσ8(z) measurements as compared with the ΛCDM results at intermediate redshifts 0.1<z<1. For parameter estimation, we use joint data from Planck Cosmic Microwave Background (CMB) likelihoods of CMB temperature and polarization angular power spectra, Barionic Acoustic Oscillations (BAO) and local measurements of Hubble constant H0 from the Hubble Space Telescope (HST). We analyze the stability of the effective Newtonian constant Geff and its agreement

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BROADBRIDGE, PHILIP, RAVINDI NANAYAKKARA, and ANDRIY OLENKO. "ON MULTIFRACTIONALITY OF SPHERICAL RANDOM FIELDS WITH COSMOLOGICAL APPLICATIONS." ANZIAM Journal 64, no. 2 (2022): 90–118. http://dx.doi.org/10.1017/s1446181122000104.

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AbstractThis paper investigates spatial data on the unit sphere. Traditionally, isotropic Gaussian random fields are considered as the underlying mathematical model of the cosmic microwave background (CMB) data. We discuss the generalized multifractional Brownian motion and its pointwise Hölder exponent on the sphere. The multifractional approach is used to investigate the CMB data from the Planck mission. These data consist of CMB radiation measurements at narrow angles of the sky sphere. The results obtained suggest that the estimated Hölder exponents for different CMB regions do change from

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Broadbridge, Philip, Ravindi Nanayakkara, and Andriy Olenko. "On multifractionality of spherical random fields with cosmological applications." ANZIAM Journal 64 (August 28, 2022): 90–118. http://dx.doi.org/10.21914/anziamj.v64.16742.

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This paper investigates spatial data on the unit sphere. Traditionally, isotropic Gaussian random fields are considered as the underlying mathematical model of the cosmic microwave background (CMB) data. We discuss the generalized multifractional Brownian motion and its pointwise Hölder exponent on the sphere. The multifractional approach is used to investigate the CMB data from the Planck mission. These data consist of CMB radiation measurements at narrow angles of the sky sphere. The results obtained suggest that the estimated Hölder exponents for different CMB regions do change from locatio

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Copi, Craig J., James Gurian, Arthur Kosowsky, Glenn D. Starkman, and Hezi Zhang. "Exploring suppressed long-distance correlations as the cause of suppressed large-angle correlations." Monthly Notices of the Royal Astronomical Society 490, no. 4 (2019): 5174–81. http://dx.doi.org/10.1093/mnras/stz2962.

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ABSTRACT The absence of large-angle correlations in the map of cosmic microwave background temperature fluctuations is among the well-established anomalies identified in full-sky and cut-sky maps over the past three decades. Suppressed large-angle correlations are rare statistical flukes in standard inflationary cosmological models. One natural explanation could be that the underlying primordial density perturbations lack correlations on large distance scales. To test this idea, we replace Fourier modes by a wavelet basis with compact spatial support. While the angular correlation function of

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Chakravarty, G. K., S. Mohanty, and G. Lambiase. "Testing theories of gravity and supergravity with inflation and observations of the cosmic microwave background." International Journal of Modern Physics D 26, no. 13 (2017): 1730023. http://dx.doi.org/10.1142/s0218271817300233.

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Cosmological and astrophysical observations lead to the emerging picture of a universe that is spatially flat and presently undertaking an accelerated expansion. The observations supporting this picture come from a range of measurements encompassing estimates of galaxy cluster masses, the Hubble diagram derived from type-Ia supernovae observations, the measurements of Cosmic Microwave Background radiation anisotropies, etc. The present accelerated expansion of the universe can be explained by admitting the existence of a cosmic fluid, with negative pressure. In the simplest scenario, this unkn

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Gaztañaga, Enrique, and K. Sravan Kumar. "CMB Parity Asymmetry from Unitary Quantum Gravitational Physics." Symmetry 17, no. 7 (2025): 1056. https://doi.org/10.3390/sym17071056.

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Longstanding anomalies in the Cosmic Microwave Background (CMB), including the low quadrupole moment and hemispherical power asymmetry, have recently been linked to an underlying parity asymmetry. We show here how this parity asymmetry naturally arises within a quantum framework that explicitly incorporates the construction of a geometric quantum vacuum based on parity (P) and time-reversal (T) transformations. This framework restores unitarity in quantum field theory in curved spacetime (QFTCS). When applied to inflationary quantum fluctuations, this unitary QFTCS formalism predicts parity as

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Jung, Gabriel, Nabila Aghanim, Jenny G. Sorce, Benjamin Seidel, Klaus Dolag, and Marian Douspis. "Revisiting the CMB large-scale anomalies: The impact of the Sunyaev-Zeldovich signal from the Local Universe." Astronomy & Astrophysics 692 (December 2024): A180. https://doi.org/10.1051/0004-6361/202451238.

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The full-sky measurements of the cosmic microwave background (CMB) temperature anisotropies by WMAP and Planck have highlighted several unexpected isotropy-breaking features on the largest angular scales. We investigate the impact of the local large-scale structure on these anomalies through the thermal and kinetic Sunyaev-Zeldovich effects. We used a constrained hydrodynamical simulation that reproduced the local Universe in a box of 500 h−1 Mpc to construct full-sky maps of the temperature anisotropies produced by these two secondary effects of the CMB, and we discuss their statistical prope

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Pranav, Pratyush. "Anomalies in the topology of the temperature fluctuations in the cosmic microwave background: An analysis of the NPIPE and FFP10 data releases." Astronomy & Astrophysics 659 (March 2022): A115. http://dx.doi.org/10.1051/0004-6361/202140291.

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We present a topological analysis of the temperature fluctuation maps from the Planck 2020 Data Release 4 NPIPE dataset and the Planck 2018 Data Release 3 FFP10 dataset. We performed a multiscale analysis in terms of the homology characteristics of the maps, invoking relative homology to account for the analysis in the presence of masks. We performed our analysis for a range of smoothing scales spanning sub- and super-horizon scales corresponding to a full width at half maximum (FWHM) of 5′,10′,20′,40′,80′,160′,320′, and 640′, and employed simulations based on the standard model for comparison

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Tiwari, Rishi Kumar, Aroonkumar Beesham, and Bhupendra Kumar Shukla. "FLRW Cosmological Models with Dynamic Cosmological Term in Modified Gravity." Universe 7, no. 9 (2021): 319. http://dx.doi.org/10.3390/universe7090319.

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Although the standard lambda cold dark matter cosmological model is quite successful in describing the universe, there are still several issues that are still not resolved. Some of these are the cosmological constant problem, certain anomalies in the cosmic microwave background radiation and whether general relativity is valid on large scales. Therefore, it is interesting to examine modified theories in an attempt to solve these problems, and to examine the entire range of possibilities that are allowed. In this work, we examine one of these modified theories, viz., f(R,T) gravity. We study th

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Macciò, Andrea V. "QSO Strong Gravitational Lensing and the Detection of Dark Halos." Proceedings of the International Astronomical Union 3, S244 (2007): 186–95. http://dx.doi.org/10.1017/s1743921307013981.

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AbstractWe present recent results concerning the possibility to detect dark satellites around galaxies using QSO strong gravitational lensing. Combining high resolution hydrodynamical simulations of galaxy formation and analytic studies we show that current QSO observations data do not present any evidence for the existence of such satellites. The amount of substructures predicted by CDM within a galaxy size dark matter halo is too low to explain the observed anomalies in the QSO images flux ratio.Nevertheless the fluxes of QSO multiple images can be used to constrain the CDM power spectrum on

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Hazra, Dhiraj Kumar, Akhil Antony, and Arman Shafieloo. "One spectrum to cure them all: signature from early Universe solves major anomalies and tensions in cosmology." Journal of Cosmology and Astroparticle Physics 2022, no. 08 (2022): 063. http://dx.doi.org/10.1088/1475-7516/2022/08/063.

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Abstract Acoustic peaks in the Cosmic Microwave Background (CMB) temperature spectrum as observed by the Planck satellite appear to be smoother than our expectation from the standard model lensing effect. This anomalous effect can be also mimicked by a spatially closed Universe with a very low value of Hubble constant that consequently aggravates the already existing discordance between cosmological observations. We reconstruct a signature from the early Universe, a particular form of oscillation in the primordial spectrum of quantum fluctuations with a characteristic frequency, that solves al

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Eskilt, Johannes R., Yashar Akrami, Stefano Anselmi, et al. "Cosmic topology. Part IIa. Eigenmodes, correlation matrices, and detectability of orientable Euclidean manifolds." Journal of Cosmology and Astroparticle Physics 2024, no. 03 (2024): 036. http://dx.doi.org/10.1088/1475-7516/2024/03/036.

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Abstract If the Universe has non-trivial spatial topology, observables depend on both the parameters of the spatial manifold and the position and orientation of the observer. In infinite Euclidean space, most cosmological observables arise from the amplitudes of Fourier modes of primordial scalar curvature perturbations. Topological boundary conditions replace the full set of Fourier modes with specific linear combinations of selected Fourier modes as the eigenmodes of the scalar Laplacian. We present formulas for eigenmodes in orientable Euclidean manifolds with the topologies E 1–E 6, E 11,

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Petretti, Catherine, Matteo Braglia, Xingang Chen, Dhiraj Kumar Hazra, and Sonia Paban. "Investigating the origin of CMB large-scale features using LiteBIRD and CMB-S4." Journal of Cosmology and Astroparticle Physics 2025, no. 06 (2025): 035. https://doi.org/10.1088/1475-7516/2025/06/035.

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Abstract Several missions following Planck are currently under development, which will provide high-precision measurements of the Cosmic Microwave Background (CMB) anisotropies. Specifically, measurements of the E modes will become nearly limited by cosmic variance, which, especially when considering the sharpness of the E-mode transfer functions, may allow for the ability to detect deviations from the concordance model in the CMB data. We investigate the capability of upcoming missions to scrutinize models that have been proposed to address large-scale anomalies observed in the temperature sp

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Allali, Itamar J., Daniel Aloni, and Nils Schöneberg. "Cosmological probes of Dark Radiation from Neutrino Mixing." Journal of Cosmology and Astroparticle Physics 2024, no. 09 (2024): 019. http://dx.doi.org/10.1088/1475-7516/2024/09/019.

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Abstract Models of stepped dark radiation have recently been found to have an important impact on the anisotropies of the cosmic microwave background, aiding in easing the Hubble tension. In this work, we study models with a sector of dark radiation with a step in its abundance, which thermalizes after big bang nucleosynthesis by mixing with the standard model neutrinos. For this, we extend an earlier work which has focused on the background evolution only until the dark sector thermalizes by deriving the full background and perturbation equations of the model and implementing them in an Einst

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Domènech, Guillem, Roya Mohayaee, Subodh P. Patil, and Subir Sarkar. "Galaxy number-count dipole and superhorizon fluctuations." Journal of Cosmology and Astroparticle Physics 2022, no. 10 (2022): 019. http://dx.doi.org/10.1088/1475-7516/2022/10/019.

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Abstract In view of the growing tension between the dipole anisotropy of number counts of cosmologically distant sources and of the cosmic microwave background (CMB), we investigate the number count dipole induced by primordial perturbations with wavelength comparable to or exceeding the Hubble radius today. First, we find that neither adiabatic nor isocurvature superhorizon modes can generate an intrinsic number count dipole. However a superhorizon isocurvature mode does induce a relative velocity between the CMB and the (dark) matter rest frames and thereby affects the CMB dipole. We revisit

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Braglia, Matteo, Xingang Chen, Dhiraj Kumar Hazra, and Lucas Pinol. "Back to the features: assessing the discriminating power of future CMB missions on inflationary models." Journal of Cosmology and Astroparticle Physics 2023, no. 03 (2023): 014. http://dx.doi.org/10.1088/1475-7516/2023/03/014.

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Abstract Future Cosmic Microwave Background (CMB) experiments will deliver extremely accurate measurements of the E-modes pattern of the CMB polarization field. Given the sharpness of the E-modes transfer functions, such surveys make for a powerful detector of high-frequency signals from primordial features that may be lurking in current data sets. With a handful of toy models that increase the fit to the latest Planck data, but are of marginal statistical significance, we use a state-of-the-art forecast pipeline to illustrate the promising prospects to test primordial features in the next dec

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Galloni, Giacomo, Mario Ballardini, Nicola Bartolo, Alessandro Gruppuso, Luca Pagano, and Angelo Ricciardone. "Unraveling the CMB lack-of-correlation anomaly with the cosmological gravitational wave background." Journal of Cosmology and Astroparticle Physics 2023, no. 10 (2023): 013. http://dx.doi.org/10.1088/1475-7516/2023/10/013.

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Abstract Since the very first observations, the Cosmic Microwave Background (CMB) has revealed on large-scales unexpected features known as anomalies, which challenge the standard Λ cold dark matter (ΛCDM) cosmological model. One such anomaly is the “lack-of-correlation”, where the measured two-point angular correlation function of CMB temperature anisotropies is compatible with zero, differently from the predictions of the standard model. This anomaly could indicate a deviation from the standard model, unknown systematics, or simply a rare realization of the model itself. In this study, we ex

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Guandalin, Caroline, Jade Piat, Chris Clarkson, and Roy Maartens. "Theoretical Systematics in Testing the Cosmological Principle with the Kinematic Quasar Dipole." Astrophysical Journal 953, no. 2 (2023): 144. http://dx.doi.org/10.3847/1538-4357/acdf46.

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Abstract The Cosmological Principle (CP) is part of the foundation that underpins the standard model of the Universe. In the era of precision cosmology, when stress tests of the standard model are uncovering various tensions and possible anomalies, it is critical to check the viability of this principle. A key test is the consistency between the kinematic dipoles of the cosmic microwave background and of the large-scale matter distribution. Results using radio continuum and quasar samples indicate a rough agreement in the directions of the two dipoles, but a larger than expected amplitude of t

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Tiwari, Rishi Kumar, Aroonkumar Beesham, and Bhupendra Kumar Shukla. "Reconstruction of Models with Variable Cosmological Parameter in f(R,T) Theory." Physical Sciences Forum 2, no. 1 (2021): 59. http://dx.doi.org/10.3390/ecu2021-09372.

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The standard ΛCDM model is reasonably successful in describing the universe, and is the most widely acceptable model in cosmology. However, there are several theoretical issues, such as the initial singularity, the cosmological constant problem, the particle nature of dark matter, the existence of anomalies in the cosmic microwave background radiation and on small scales, the predictions and tests of the inflationary scenario and whether general relativity is valid on the largest possible scales. Hence, there is growing interest in looking at modified theories. In this presentation, a reconstr

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Kovács, A., N. Jeffrey, M. Gatti, et al. "The DES view of the Eridanus supervoid and the CMB cold spot." Monthly Notices of the Royal Astronomical Society 510, no. 1 (2021): 216–29. http://dx.doi.org/10.1093/mnras/stab3309.

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ABSTRACT The Cold Spot is a puzzling large-scale feature in the Cosmic Microwave Background temperature maps and its origin has been subject to active debate. As an important foreground structure at low redshift, the Eridanus supervoid was recently detected, but it was subsequently determined that, assuming the standard ΛCDM model, only about 10–20 per cent of the observed temperature depression can be accounted for via its Integrated Sachs–Wolfe imprint. However, R ≳ 100 h−1Mpc supervoids elsewhere in the sky have shown ISW imprints AISW ≈ 5.2 ± 1.6 times stronger than expected from ΛCDM (AIS

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Gaztañaga, Enrique, and K. Sravan Kumar. "Finding origins of CMB anomalies in the inflationary quantum fluctuations." Journal of Cosmology and Astroparticle Physics 2024, no. 06 (2024): 001. http://dx.doi.org/10.1088/1475-7516/2024/06/001.

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Abstract In this paper, we present compelling evidence for the parity asymmetry (a discrete symmetry separate from isotropy) in the Cosmic Microwave Background (CMB) map, measured through two-point temperature correlations. Any asymmetry associated with discrete symmetries, such as parity, challenges our understanding of quantum physics associated with primordial physics rather than LCDM (Λ Cold-Dark-Matter) itself. We commence by conducting a comprehensive analysis of the Planck CMB, focusing on the distribution of power in low-multipoles and temperature anticorrelations at parity conjugate p

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Akrami, Y., M. Ashdown, J. Aumont, et al. "Planck2018 results." Astronomy & Astrophysics 641 (September 2020): A7. http://dx.doi.org/10.1051/0004-6361/201935201.

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Analysis of thePlanck2018 data set indicates that the statistical properties of the cosmic microwave background (CMB) temperature anisotropies are in excellent agreement with previous studies using the 2013 and 2015 data releases. In particular, they are consistent with the Gaussian predictions of the ΛCDM cosmological model, yet also confirm the presence of several so-called “anomalies” on large angular scales. The novelty of the current study, however, lies in being a first attempt at a comprehensive analysis of the statistics of the polarization signal over all angular scales, using either

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Owusu, Stephen, Pedro da Silveira Ferreira, Alessio Notari, and Miguel Quartin. "The CMB cold spot under the lens: ruling out a supervoid interpretation." Journal of Cosmology and Astroparticle Physics 2023, no. 06 (2023): 040. http://dx.doi.org/10.1088/1475-7516/2023/06/040.

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Abstract The Cosmic Microwave Background (CMB) anisotropies are thought to be statistically isotropic and Gaussian. However, several anomalies are observed, including the CMB Cold Spot, an unexpected cold ∼ 10° region with p-value ≲ 0.01 in standard ΛCDM. One of the proposed origins of the Cold Spot is an unusually large void on the line of sight, that would generate a cold region through the combination of integrated Sachs-Wolfe and Rees-Sciama effects. In the past decade extensive searches were conducted in large scale structure surveys, both in optical and infrared, in the same area for z ≲

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Galloni, Giacomo, Nicola Bartolo, Sabino Matarrese, Marina Migliaccio, Angelo Ricciardone, and Nicola Vittorio. "Test of the statistical isotropy of the universe using gravitational waves." Journal of Cosmology and Astroparticle Physics 2022, no. 09 (2022): 046. http://dx.doi.org/10.1088/1475-7516/2022/09/046.

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Abstract 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 detecto

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Eingorn, Maxim, Andrew McLaughlin II, Ezgi Canay, Maksym Brilenkov, and Alexander Zhuk. "Gravitation in the Space with Chimney Topology." Physical Sciences Forum 2, no. 1 (2021): 32. http://dx.doi.org/10.3390/ecu2021-09295.

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Searching for possible indicators of spatial topology of the Universe in the Cosmic Microwave Background data, one recognizes a quite promising interpretation which suggests that the shape of the space manifests itself in the form of anomalies in the large angular scale observations, such as the quadrupole and octopole alignment. Motivated by the presumptive existence of such a tempting connection, we study the chimney topology, T×T×R, which belongs to the class of toroidal topologies with a preferred direction. The infinite axis in this case may be attributed to the preferred axis of the afor

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