Cosmological Component Research Articles

Analysis of the Hubble Tension and Modifications to the Standard Cosmological Model

The Hubble constant is crucial to the knowledge of the universe’s nature and expansion, remaining as an active area for research in the recent decades. Cosmological microwave background observations revealed a lower value of 67–69 km-1s-1Mpc for the Hubble constant, but local data showed a higher value of 73–75 km-1s-1Mpc. This study focuses on the Hubble constant and its measurement, systematic uncertainties, observed tension, and potential modifications to the standard cosmological model. To be specific, this paper aims to address the tension between different measurement methods, which are Cepheid variables and supernovae, Baryon Acoustic Oscillations, and Gravitational waves, and understand systematic uncertainties. Results show discrepancies in Hubble constant values, indicating potential modifications to the standard cosmological model. Prospects include exploring alternative cosmological components and enhanced detection and computation methods. The study's implications lie in advancing the understanding of the expanding universe and guiding future research directions regarding to Hubble tension measurement.

“Bats are our identity”: the role of bats as urban identity in Watansoppeng city, Indonesia

ABSTRACTThe study of urban identity in urban planning and design literature often pays attention to architectural elements and geographical landscapes. These components are considered features that make a city easy to remember and distinguish it from others, but biotic elements also have the potential to form these identities. Reports showed that these elements are not maintained in urban regeneration projects. Therefore, this study aimed to reveal the role of biotic elements as urban identity, with the case of bats in Watansoppeng. Data were collected using interviews, observation, and documentation. They were then analyzed qualitatively with the directed content analysis method using the ATLAS.ti 22 software. The results showed the significant role of bats as a form of urban identity through visual, behavioural, and cerebral components. Another role was found through the cosmological component of the community. Bats are not only the city’s uniqueness but have also become an élan vital.

Nembe Cultural Festivals of Nigeria: African Culture Notes

Cultural festivals are increasingly becoming arenas of discourse for scholars to express their innate views about the cosmological component of a society on a wider social, cultural and political scales. Thus, galvanizing debates that invariably polarizes between those advocating change and those preserving tradition in the face of globalization. This paper however analyzes the significance of cultural festivals among the Nembe people of Ijo ethnicity of Nigeria. Thus, the paper informs that generally festival and its cultural contents is the livewire that have been appropriately utilized to keep alive the cultural history of what becomes the collective or historical memory of the people concerned; which links them to their past. This ostensibly underpins the collective sustainability of the meaning, importance, as well as the role festival plays in the history of Nembe society of all ages. The findings revealed that festival was and is a major source of history as well as history in its own right among non-literate societies of the globe for historical, aesthetic, as wel as existential purposes. The methodological approach in this paper was historical anthropology where primary and secondary data collection were subjected to varying content analysis for utilization informed the conclusion reached.

NEMBE CULTURAL FESTIVALS OF NIGERIA: AFRICAN CULTURE NOTES

Cultural festivals are increasingly becoming arenas of discourse for scholars to express their innate views about the cosmological component of a society on a wider social, cultural and political scales. Thus, galvanizing debates that invariably polarizes between those advocating change and those preserving tradition in the face of globalization. This paper however analyzes the significance of cultural festivals among the Nembe people of Ijo ethnicity of Nigeria. Thus, the paper informs that generally festival and its cultural contents is the livewire that have been appropriately utilized to keep alive the cultural history of what becomes the collective or historical memory of the people concerned; which links them to their past. This ostensibly underpins the collective sustainability of the meaning, importance, as well as the role festival plays in the history of Nembe society of all ages. The findings revealed that festival was and is a major source of history as well as history in its own right among non-literate societies of the globe for historical, aesthetic, as wel as existential purposes. The methodological approach in this paper was historical anthropology where primary and secondary data collection were subjected to varying content analysis for utilization informed the conclusion reached.

The Peculiarity of N.A. Berdyaev’s Philosophical Discourse

To refute the opinion about the chaotic presentation of problems in Berdyaev’s texts, the dominant of the unconscious, means to fall into ontological dependence on them. In the literal sense, these are not conclusions drawn on the basis of an analysis of N.A. Berdyaev’s work, but quoting the philosopher’s self-assessment, to which he resorted more than once. They have no analytical and heuristic value. N.A. Berdyaev’s way of thinking simultaneously contains Christian intuitions and an oppositional structure characteristic of philosophical creativity in general. The peculiarities of the Russian philosopher’s thinking are reflected in the fact that such types of philosophical creativity as personalism, existentialism, as well as intuitive components of the Eastern Christian worldview are organically combined. In the philosophy of N.A. Berdyaev there are also cosmological components, which contain the statement that the world is entering the era of the third period, which is expressed in its structure contains the statement that the time for freedom and creativity is coming. The peculiarities of N.A. Berdyaev’s thinking can be evaluated from the point of view of aesthetics and uniqueness, which significantly distinguish his way of thinking from the typical development of philosophical thinking of Modern times. According to the Russian philosopher, analysis and splitting cannot serve as a starting point for the thought process. Without creativity and freedom, the philosophy of the non-classical period has no significance and significance, because the potential of formal and dialectical logic has already clearly and fundamentally affected the best examples of classical philosophy. The third level is binarism, which formally has generic signs of the organization of problematic thinking of logocentric sciences, but the specific differences are too striking to pass by them without specifying anything.

Effect of the cosmological parameters on gravitational waves: general analysis

Some time ago it was pointed out that the presence of cosmological components could affect the propagation of gravitational waves (GW) beyond the usual cosmological redshift and that such effects might be observable in pulsar timing arrays (PTA). These analyses were done at leading order in the Hubble constant H 0, which is proportional to and (ρ i being the various cosmological fluid densities). In this work, we study in detail the propagation of metric perturbations on a Schwarzschild–de Sitter (SdS) background, close to the place where GW are produced, and obtain solutions that incorporate corrections linear in ρ i and Λ. At the next-to-leading order the corrections do not appear in the form of H 0 thus lifting the degeneracy among the various cosmological components. We also determine the leading corrections proportional to the mass of the final object; they are very small for the distances considered in PTA but may be of relevance in other cases. When transformed into comoving coordinates, the ones used in cosmological measurements, this SdS solution does satisfy the perturbation equations in a Friedmann–Lemaître–Robertson–Walker metric up to and including terms. This analysis is then extended to the other cosmological fluids, allowing us to consider GW sources in the Gpc range. Finally, we investigate the influence of these corrections in PTA observations.

Relation between varying fine structure constant and cosmological components

We propose a simple model based on the assumption that the varying fine structure constant $\ensuremath{\alpha}$ is an effect of the cosmological expansion to investigate the relation between the varying $\ensuremath{\alpha}$ and the cosmological components. For a spatially flat, homogeneous, and isotropic universe, the current proportion of cosmological components and age of the universe predicted by the model are consistent with the cosmological observations. Furthermore, the predicted current variation rate of $\ensuremath{\alpha}$ is also close to the atomic clock measurements. For the early universe, we predict a very strict constraint, which is compatible with the upper limit given by the investigations of cosmic microwave background and big bang nucleosynthesis.

A nontrivial footprint of standard cosmology in the future observations of low-frequency gravitational waves

Recent research shows that the cosmological components of the Universe should influence on the propagation of Gravitational Waves (GWs) and even it has been proposed a new way to measure the cosmological constant using Pulsar Timing Arrays (PTAs). However, these results have considered very particular cases (e.g. a de Sitter Universe or a mixing with non-relativistic matter). In this work we propose an extension of these results, using the Hubble constant as the natural parameter that includes all the cosmological information and studying its effect on the propagation of GWs. Using linearized gravity we considered a mixture of perfect fluids permeating the spacetime and studied the propagation of GWs within the context of the \(\Lambda \hbox {CDM}\) model. We found from numerical simulations that the timing residual of local pulsars should present a distinguishable peak depending on the local value of the Hubble constant. As a consequence, when assuming the standard \(\Lambda \hbox {CDM}\) model, our result predicts that the region of maximum timing residual is determined by the redshift of the source. This framework represents an alternative test for the standard cosmological model, and it can be used to facilitate the measurements of gravitational waves by ongoing PTAs projects.

Comparison of the Planck 2018 CMB polarization maps in the BICEP2/Keck region

We examine the statistical properties of polarization maps from Planck 2018 within the patch of sky observed by the BICEP2/Keck experiment using the one point distribution function (1PDF), skewness, and kurtosis statistics. Our analysis is performed for the Q and U Stokes parameters and for the corresponding E- and B-modes of the CMB signals. We extend our analysis by studying the correlations between CMB polarization maps and residual maps (the difference between the full signal and the CMB map) for the frequency range of 100–217 GHz with both the Q/U and E/B approaches. Although all the CMB maps reveal almost Gaussian statistical properties for Q/U and E/B domains, we have detected very significant anomalies for cross-correlations with residuals at 100 GHz at the level of 3.7σ for the Commander map and 5.2σ for NILC, for both the Q and U parameters. Using the NILC-Commander difference, which does not contain a cosmological signal, we find a sub-dominant non-Gaussian component in Q skewness and kurtosis at the level of 4.3σ and 10σ, respectively. For the B-mode we have found a very high level of cross-correlation (0.63–0.69) between the NILC/Commander maps and the 143 GHz total signal, which cannot be associated with the cosmological component. These strong deviations suggest that remnants of foregrounds, systematic effects, and component separation exist in the 2018 Planck CMB polarization maps in the BICEP2 sky area, which is far away from the Galactic plane. Our analysis also demonstrates the preferability of the Q/U domain over E/B for determination of the statistical properties of the derived CMB signals, due to non-locality of the transition Q/U → E/B.

K-evolution: a relativistic N-body code for clustering dark energy

We introduce k-evolution, a relativistic N-body code based on gevolution, which includes clustering dark energy among its cosmological components. To describe dark energy, we use the effective field theory approach. In particular, we focus on k-essence with a speed of sound much smaller than unity but we lay down the basis to extend the code to other dark energy and modified gravity models. We develop the formalism including dark energy non-linearities but, as a first step, we implement the equations in the code after dropping non-linear self-coupling in the k-essence field. In this simplified setup, we compare k-evolution simulations with those of CLASS and gevolution 1.2, showing the effect of dark matter and gravitational non-linearities on the power spectrum of dark matter, of dark energy and of the gravitational potential. Moreover, we compare k-evolution to Newtonian N-body simulations with back-scaled initial conditions and study how dark energy clustering affects massive halos.

Proposal for a Real-Time Detection of our Acceleration through Space.

Our proper acceleration with respect to the cosmic microwave background results in a real-time change of the angular position of distant extragalactic sources. The cosmological component of this aberration drift signal, the noninertial motion generated by the large-scale distribution of matter, can, in principle, be detected by future high-precision astrometric experiments. It will provide interesting consistency tests of the standard model of cosmology, set independent constraints on the amplitude of the Hubble constant and the linear growth rate of cosmic structures, and be instrumental in searching for evidence of new physics beyond the standard model. We present the formalism of this novel cosmological test, discuss the physics to which it is sensitive, and show simulated forecasts of the accuracy with which it can be implemented.

A dynamical weak scale from inflation

Dynamical scanning of the Higgs mass by an axion-like particle during inflation may provide a cosmological component to explaining part of the hierarchy problem. We propose a novel interplay of this cosmological relaxation mechanism with inflation, whereby the backreaction of the Higgs vacuum expectation value near the weak scale causes inflation to end. As Hubble drops, the relaxion's dissipative friction increases relative to Hubble and slows it down enough to be trapped by the barriers of its periodic potential. Such a scenario raises the natural cut-off of the theory up to ∼ 1010 GeV, while maintaining a minimal relaxion sector without having to introduce additional scanning scalars or new physics coincidentally close to the weak scale.

When the universe expands too fast: relentless dark matter

We consider a modification to the standard cosmological history consisting of introducing a new species ϕ whose energy density red-shifts with the scale factor a like ρϕ ∝ a−(4+n). For 0n>, such a red-shift is faster than radiation, hence the new species dominates the energy budget of the universe at early times while it is completely negligible at late times. If equality with the radiation energy density is achieved at low enough temperatures, dark matter can be produced as a thermal relic during the new cosmological phase. Dark matter freeze-out then occurs at higher temperatures compared to the standard case, implying that reproducing the observed abundance requires significantly larger annihilation rates. Here, we point out a completely new phenomenon, which we refer to as relentless dark matter: for large enough n, unlike the standard case where annihilation ends shortly after the departure from thermal equilibrium, dark matter particles keep annihilating long after leaving chemical equilibrium, with a significant depletion of the final relic abundance. Relentless annihilation occurs for n ⩾ 2 and n ⩾ 4 for s-wave and p-wave annihilation, respectively, and it thus occurs in well motivated scenarios such as a quintessence with a kination phase. We discuss a few microscopic realizations for the new cosmological component and highlight the phenomenological consequences of our calculations for dark matter searches.

Cosmological Landscapes and Exotic Gods: American Indian Rock Art in Arkansas

American Indian rock art is distributed across a portion of the east-flowing Arkansas River Valley in a distinctive spatial pattern in which motifs and compositions referencing spirit world subject matter predominate along the north side of the river, in contrast to imagery depicting the observable world on the south. This pattern accords with cosmological components of the belief systems of Dhegiha Siouan-speaking tribes, as expressed in the spatial elements of other cultural phenomena, including village layouts and ritual choreographies, among such groups as the Osage and Quapaw, who occupied the region during later historic times. One sandstone prominence also located south of the river attracted the attention of Precolumbian artists, who decorated its exposed surfaces with an intriguing depiction of a mask, partly obscured by lichen, exhibiting the telltale eyes and other characteristics of the Mesoamerican rain god Tlaloc. Examination of this image, along with a second possible Mesoamerican- or Southwestern-inspired image located north of the river, serves to enlarge our understanding of the wider distributional pattern, especially on the topic of how local communities incorporated exotic ideas into the fabric of their cosmological landscapes.

The effect of a massive object on an expanding universe

A tetrad-based procedure is presented for solving Einstein’s field equations for spherically symmetric systems; this approach was first discussed by Lasenby, Doran & Gull in the language of geometric algebra. The method is used to derive metrics describing a point mass in a spatially flat, open and closed expanding universe, respectively. In the spatially flat case, a simple coordinate transformation relates the metric to the corresponding one derived by McVittie. Nonetheless, our use of non-comoving (‘physical’) coordinates greatly facilitates physical interpretation. For the open and closed universes, our metrics describe different space–times to the corresponding McVittie metrics and we believe the latter to be incorrect. In the closed case, our metric possesses an image mass at the antipodal point of the universe. We calculate the geodesic equations for the spatially flat metric and interpret them. For radial motion in the Newtonian limit, the force acting on a test particle consists of the usual 1/r2 inwards component due to the central mass and a cosmological component proportional to r that is directed outwards (inwards) when the expansion of the universe is accelerating (decelerating). For the standard Λ cold dark matter concordance cosmology, the cosmological force reverses direction at about z≈ 0.67. We also derive an invariant fully general relativistic expression, valid for arbitrary spherically symmetric systems, for the force required to hold a test particle at rest relative to the central point mass.

Bayesian source separation for cosmology

Recent satellite missions have provided and continue to provide us with vast amounts of data on radiation measurements that generally present themselves as superpositions of various cosmological sources, most importantly cosmic microwave background (CMB) radiation and other galactic and extragalactic sources. We would like to obtain the estimates of these sources separately since they carry vital information of cosmological significance about our Universe. Although initial attempts to obtain sources have utilized blind estimation techniques, the presence of important astrophysical prior information and the demanding nature of the problem makes the use of informed techniques possible and indispensable. In this article, our objective is to present a formulation of the problem in Bayesian framework for the signal processing community and to provide a panorama of Bayesian source separation techniques for the estimation of cosmological components from the observation mixtures.

A homogeneous multicomponent cosmological model with interacting spinor, scalar, and vector fields in the presence of dark energy

The evolution of a homogeneous multicomponent cosmological model with interacting spinor, vector, and scalar fields in the presence of dark energy described by the ideal liquid with the corresponding state equation is considered. The source of the vector and spinor fields is the kinetic energy of the inflation (scalar) field that is modeled by introduction of Lagrangians for the spinor and vector fields interacting with the scalar field through the squared gradient. A system of the dynamic Einstein–Proca–Klein–Fock and ideal liquid equations in the presence of interaction of the cosmological model components is solved. The role of individual components in the process of model evolution is elucidated.

Intrinsic Redshifts and the Tully–Fisher Distance Scale

The Tully–Fisher relationship (TFR) has been shown to have a relatively small observed scatter of ∼±0.35 mag implying an intrinsic scatter < ±0.30 mag. However, when the TFR is calibrated from distances derived from the Hubble relation for field galaxies scatter is consistently found to be ±0.64 to ±0.84 mag. This significantly larger scatter requires that intrinsic TFR scatter is actually much larger than ±0.30 mag, that field galaxies have an intrinsic TFR scatter much larger than cluster spirals, or that field galaxies have a velocity dispersion relative to the Hubble flow in excess of 1000 km s−1. Each of these potential explanations faces difficulties and contradicted by available data and the results of previous studies. An alternative explanation is that the measured redshifts of galaxies are composed of a cosmological redshift component predicted from the value of the Hubble constant and a superimposed intrinsic redshift component previously identified in other studies. This intrinsic redshift component may exceed 5000 km s−1 in individual galaxies. In this alternative scenario a possible value for the Hubble constant is 55–60 km s−1 Mpc−1.

Limits on the detectability of the CMB B-mode polarization imposed by foregrounds

We investigate which practical constraints are imposed by foregrounds to the detection of the B-mode polarization generated by gravitational waves in the case of experiments of the type currently being planned. Because the B-mode signal is probably dominated by foregrounds at all frequencies, the detection of the cosmological component depends drastically on our ability for removing foregrounds. We provide an analytical expression to estimate the level of the residual polarization for Galactic foregrounds, according to the method employed for their subtraction. We interpret this result in terms of the lower limit of the tensor-to-scalar ratio r that allows to disentangle the cosmological B-mode polarization from the foregrounds contribution. Polarized emission from extragalactic radio sources and gravitational lensing is also taken into account. As a first approach, we consider the ideal limit of an instrumental noise--free experiment: for a full--sky coverage and a degree resolution, we obtain a limit of r~10^(-4). This value can be improved by high--resolution experiments and, in principle, no clear fundamental limit on the detectability of gravitational waves polarization is found. Our analysis is also applied to planned or hypothetical future polarization experiments, taking into account expected noise levels.

Distances of Quasars and Quasar‐like Galaxies: Further Evidence That Quasi‐stellar Objects May Be Ejected from Active Galaxies

If high-redshift quasi-stellar objects (QSOs) are ejected from the nuclei of low-redshift galaxies, as some have claimed, a large portion of their redshift must be intrinsic (non-Doppler). If these intrinsic components have preferred values, redshifts will tend to cluster around these preferred values and produce peaks in the redshift distribution. Doppler ejection and Hubble flow components will broaden each peak. Because ejection velocities are randomly directed and Hubble flow components are always positive, in this model all peaks are expected to show an asymmetry, extending farther out in the red wing. If peaks are present showing this predicted asymmetry, it can lead directly to an estimate of quasar distances. Using two quasar samples, one with high redshifts and one with low, it is shown here that not only do all peaks in these two redshift distributions occur at previously predicted preferred values, but also they all show the predicted extra extension in the red wing. For the low- and high-redshift samples the mean cosmological components are found to be zc ~ 0.024 and ~0.066, respectively. The difference can be explained by the improved detection limit of the high-redshift sample. These results offer further evidence in favor of the model proposing that QSOs are ejected from active galaxies.