Evolution Of The Universe Research Articles

Gravitational waves produced by domain walls during inflation

We study the properties of the stochastic gravitational-wave background (SGWB) produced by domain walls (DWs) during inflation without forming a network. We numerically simulate the DW production caused by a second-order phase transition and calculate the SGWB spectrum using a 1000×1000×1000 lattice. We show that the SGWB can be observed directly by future terrestrial and space gravitational-wave detectors and through the B-mode spectrum in the cosmic microwave background. With numerical simulations, we derive an empirical formula for the strength and qualitative features of the SGWB spectrum. The details of the SGWB spectrum also contain information about the later evolution of the Universe. Published by the American Physical Society 2024

Near- and sub-solar-mass naked singularities and black holes from transmutation of white dwarfs

Recent gravitational wave events have suggested the existence of near-solar-mass black holes which cannot be formed via stellar evolution. This has opened up a tantalizing possibility of future detections of both black holes and naked singularities in this mass range. Existence of naked singularities is a topical and fundamental physics issue, but their formation mechanism is not yet clear. Here, we show that some white dwarfs can realistically transmute into black holes and naked singularities with a wide range of near- and sub-solar-mass values by capturing asymmetric or non-self-annihilating primordial dark matter (PDM) particles. We argue that, while a type Ia supernova due to the accumulation of dark matter at the core of a white dwarf could also be a possibility, the transmutation of a white dwarf into a black hole or a naked singularity is a viable consequence of the capture of non-self-annihilating PDM particles. These white dwarf transmutations can have a significant role in probing the physics of dark matter and compact objects, and could be tested using the rates and locations of mergers over the cosmological time scale.

Optical Variability of Blazars in the Tomo-e Gozen Northern Sky Transient Survey

We studied the optical variability of 241 BL Lacertae (BL Lacs) and 83 flat-spectrum radio quasars (FSRQs) from the 4LAC catalog using data from the Tomo-e Gozen Northern Sky Transient Survey, with ∼50 epochs per blazar on average. We excluded blazars whose optical variability may be underestimated due to the influence of their host galaxy based on their optical luminosity (L O ). FSRQs with γ-ray photon index greater than 2.6 exhibit very low optical variability, and their distribution of standard deviation of repeated photometry is significantly different from that of the other FSRQs (Kolmogorov–Smirnov test p-value equal to 5 × 10−6). Among a sample of blazars at any particular cosmological epoch, those with lower γ-ray luminosity (L γ ) tend to have lower optical variability, and those FSRQs with a γ-ray photon index greater than 2.6 tend to have low L γ . We also measured the structure function of optical variability and found that the amplitude of the structure function for FSRQs is higher than previously measured and higher than that of BL Lacs at multiple time lags. Additionally, the amplitude of the structure function of FSRQs with high γ-ray photon index is significantly lower than that of FSRQs with low γ-ray photon index. The structure function of FSRQs of high γ-ray photon index shows a characteristic timescale of more than 10 days, which may be the variability timescale of the accretion disk. In summary, we infer that the optical component of FSRQs with high γ-ray photon index may be dominated by the accretion disk.

Probing New physics with high-redshift quasars: axions and non-standard cosmology

The Hubble diagram of quasars, as candidates to “standardizable” candles, has been used to measure the expansion history of the Universe at late times, up to very high redshifts (z ∼ 7). It has been shown that this history, as inferred from the quasar dataset, deviates at ≳ 3σ level from the concordance (ΛCDM) cosmology model preferred by the cosmic microwave background (CMB) and other datasets. In this article, we investigate whether new physics beyond ΛCDM (BΛCDM) or beyond the Standard Model (BSM) could make the quasar data consistent with the concordance model. We first show that an effective redshift-dependent relation between the quasar UV and X-ray luminosities, complementing previous phenomenological work in the literature, can potentially remedy the discrepancy. Such a redshift dependence can be realized in a BSM model with axion-photon conversion in the intergalactic medium (IGM), although the preferred parameter space is in tension with various other astrophysical constraints on axions, at a level depending on the specific assumptions made regarding the IGM magnetic field. We briefly discuss a variation of the axion model that could evade these astrophysical constraints. On the other hand, we show that models beyond ΛCDM such as one with a varying dark energy equation of state (wCDM) or the phenomenological cosmographic model with a polynomial expansion of the luminosity distance, cannot alleviate the tension. The code for our analysis, based on emcee [1] and corner.py [2], is publicly available at github.com/ChenSun-Phys/high_z_candles.

Requiem to “proof of inflation” or sourced fluctuations in a non-singular bounce

Popular wisdom suggests that measuring the tensor to scalar ratio r on CMB scales is a “proof of inflation” since one generic prediction is a scale-invariant tensor spectrum while alternatives predict r that is many orders of magnitude below the sensitivity of future experiments. A bouncing Universe with sourced fluctuations allows for nearly scale-invariant spectra of both scalar and tensor perturbations challenging this point of view. Past works have analyzed the model until the bounce, under the assumption that the bounce will not change the final predictions. In this work, we discard this assumption. We explicitly follow the evolution of the Universe and fluctuations across the bounce until reheating. The evolution is stable, and the existence of the sourced fluctuations does not destroy the bounce. The bounce enhances the scalar spectrum while leaving the tensor spectrum unchanged. The enhancement depends on the duration of the bounce — a shorter bounce implies a larger enhancement. The model matches current observations and predicts any viable tensor-to-scalar ratio r ≲ 10-2, which may be observed in upcoming CMB experiments. Hence, a measurement of r will no longer be a “proof of inflation”, and a Sourced Bounce is a viable paradigm with distinct predictions.

Трансцендентные измерения танцевальной античной культуры

The article presents a study of sacred dances in ancient culture. The origins of dance and their connection with the mysteries are considered. The approach to dance as a language born in the infancy of mankind and closely related to myth allows identifying the semantic units of dance which express the mythological foundations of the creation of the universe and the birth of order from chaos. The procedure of understanding mythological meanings is based on the identification of symmetry structures. The authors of the article analyse the forms of dance compositions as systems of non‐verbal semantic constructs and study the image of the Labyrinth in the choreographic ancient tradition as a symbol of mastering and accumulating experience with subsequent transformation and comprehension of a new development stage of the soul.

Growth history and quasar bias evolution at z < 3 from Quaia

We make use of the Gaia-unWISE quasar catalogue, Quaia, to constrain the growth history out to high redshifts from the clustering of quasars and their cross-correlation with maps of the Cosmic Microwave Background (CMB) lensing convergence. Considering three tomographic bins, centred at redshifts z̅i = [0.69, 1.59, 2.72], we reconstruct the evolution of the amplitude of matter fluctuations σ 8(z) over the last ∼ 12 billion years of cosmic history. In particular, we make one of the highest-redshift measurements of σ 8 (σ 8(z = 2.72) = 0.22 ± 0.06), finding it to be in good agreement (at the ∼ 1σ level) with the value predicted by ΛCDM using CMB data from Planck. We also used the data to study the evolution of the linear quasar bias for this sample, finding values similar to those of other quasar samples, although with a less steep evolution at high redshifts. Finally, we study the potential impact of foreground contamination in the CMB lensing maps and, although we find evidence of contamination in cross-correlations at z ∼ 1.7 we are not able to clearly pinpoint its origin as being Galactic or extragalactic. Nevertheless, we determine that the impact of this contamination on our results is negligible.

OLAMNI YARATILISHI HAQIDAGI AFSONALAR

This article provides scientific information about the myths about the creation of the universe. Creation myths are stories that describe the origin of the world, humanity, and the universe. Typically, creation myths are part of a larger mythological framework and often reflect the values, beliefs, and environment of the cultures that created them.

Kritik Argumen Kosmologis Al-Ghazali terhadap Konsep Penciptaan Alam menurut Stephen Hawking

In the existence of God, the cosmological argument rests on the novelty aspect of nature. Although the big bang theory supports the assumption that nature has a beginning, according to Stephen Hawking, nature can begin independently without God's intervention. The purpose of this research is to show the failure of the concept of the creation of the universe according to Stephen Hawking through Al-Ghazali's cosmological argument. The problem formulations that need to be answered are: (1) what is Stephen Hawking's view on the big bang theory, leading him to conclude that the universe could have been created independently?; and (2) how is the construction of Al-Ghazali's cosmological argument relevant to criticize this view? The approach in this research is a research model on scientific theory. With the material object in the form of the concept of the creation of the universe according to Stephen Hawking which is reviewed through the formal object of Al-Ghazali's cosmological argument. This research results in conclusions. First, Stephen Hawking's view of the big bang theory based on scientific determinism has consequences for deism and atheism. Second, the construction of Al-Ghazali's cosmological argument is relevant based on his criticism of the emanation theory which has identical consequences with Stephen Hawking's scientific determinism view. The critique shows that it is impossible for the universe to be created out of nothing independently, because the creation of the universe at a certain time requires the existence of a principle of determination and the determinant factor also requires a willing personal agent, namely God. Another implication of this argument is that God has absolute power and freedom, both to create the universe or not and to intervene in its course.

Measuring the gas reservoirs in 108 &lt; M⋆ &lt; 1011 M⊙ galaxies at 1 ≤ z ≤ 3

Context. Understanding the gas content in galaxies, along with its consumption and replenishment, is vital to our grasp of the evolution of the Universe. Numerous studies have addressed this notion, utilizing various observational tools and analytical methods. These include examining low-transition 12CO millimeter rotational lines and exploring the far-infrared and the (sub-)millimeter emission of galaxies. With the capabilities of present-day facilities, much of this research has been centered on relatively bright galaxies. Aims. This study is aimed at exploring the gas reservoirs of a more general type of galaxy population at 1.0 &lt; z &lt; 3.0 that is not restricted to bright (sub-)millimeter objects. We strive to obtain a measurement that will help to constrain our knowledge of the gas content at 1010 − 11 M⊙, with upper limits at ∼108 − 10 M⊙. Methods. We stacked ALMA 1.1 mm data to measure the gas content of a mass-complete sample of galaxies down to ∼108.6 M⊙ at z = 1 (∼109.2 M⊙ at z = 3) extracted from the HST/CANDELS sample in GOODS-S. The selected sample is composed of 5530 predominantly blue (⟨b − i⟩∼0.12 mag, ⟨i − H⟩∼0.81 mag), star-forming main sequence (MS) objects (ΔMS = log SFR−log SFRMS ∼ −0.03 dex). Results. At 1010 − 11 M⊙, our gas fractions (fgas = Mgas/(Mgas + M⋆)), ranging from 0.32 to 0.48 at these redshifts, are in good agreement with other studies based on mass-complete samples down to 1010 M⊙. These values are, however, lower than expected, according to other works more biased to individual detections. At 109 − 10 M⊙, we obtained 3σ upper limits for the fgas values ranging from 0.69 to 0.77. At 108 − 9 M⊙, these upper limits rise to ∼0.97. The upper limits at 109 − 10 M⊙ are on the level of the extrapolations of scaling relations based on mass-complete samples and below those based on individual detections. As such, these results suggest that the gas content of low-mass galaxies is, at most, equivalent to what has been extrapolated from the literature scaling relations based on mass-complete samples down to 1010 M⊙. Overall, the comparison of our results with the literature reflects how the inclusion of bluer, less obscured, and more MS-like objects progressively pushes the gas content down to lower values.

The fireball of November 24, 1970, as the most probable source of the Ischgl meteorite

AbstractThe discovery of the Ischgl meteorite unfolded in a captivating manner. In June 1976, a pristine meteorite stone weighing approximately 1 kg, fully covered with a fresh black fusion crust, was collected on a mountain road in the high‐altitude Alpine environment. The recovery took place while clearing the remnants of a snow avalanche, 2 km northwest of the town of Ischgl in Austria. Subsequent to its retrieval, the specimen remained tucked away in the finder's private residence without undergoing any scientific examination or identification until 2008, when it was brought to the University of Innsbruck. Upon evaluation, the sample was classified as a well‐preserved LL6 chondrite, with a W0 weathering grade, implying a relatively short time between the meteorite fall and its retrieval. To investigate the potential connection between the Ischgl meteorite and a recorded fireball event, we have reviewed all documented fireballs ever photographed by German fireball camera stations. This examination led us to identify the fireball EN241170 observed in Germany by 10 different European Network stations on the night of November 23/24, 1970, as the most likely candidate. We employed state‐of‐the‐art techniques to reconstruct the fireball's trajectory and to reproduce both its luminous and dark flight phases in detail. We find that the determined strewn field and the generated heat map closely align with the recovery location of the Ischgl meteorite. Furthermore, the measured radionuclide data reported here indicate that the pre‐atmospheric size of the Ischgl meteoroid is consistent with the mass estimate inferred from our deceleration analysis along the trajectory. Our findings strongly support the conclusion that the Ischgl meteorite originated from the EN241170 fireball, effectively establishing it as a confirmed meteorite fall. This discovery enables to determine, along with the physical properties, also the heliocentric orbit and cosmic history of the Ischgl meteorite.

Creators’ Creation of the Universe: An Ecological Implication in Chait Mundhum

This article deals with the creators’ creation of the universe as an ecologically interconnected world in Bairagi Kainla’s Chait Mundhum. The whole ecosphere and its components—biotic and abiotic—are not good and beautiful until the earth and human being is created by Tagera Ningwaphu Mang and her successor, Porokmi Mang. In initial phase, Tagera Ningwaphu Mang perceives her creation not suitable. She creates five major abiotic substances: sky, sun, air, earth, and water to address this problem. The middle phase extends with the beautification of earth by Porokmi Mang creating several organisms and species such as forests, flowers, insects, animals and mammals. The creators also manage water to each biotic and abiotic factor. To sustain the created world, each organisms and species are afforded with food and shelter. The creators become satisfied only in their final creation of man. They evaluate their creation beautiful and perfect in complementary existence of other things. Everything is interconnected in the creation. Therefore, Chait Mundhum mentions these ecological features implicated in the creation of the universe. To back up this, Barry Commoner’s principle of ecology has been used as a theoretical model. Subsequent Mundhums associated with this theme has also been used to support the claim. The article will be useful to those researchers and critics who want to study other Mundhums from the ecological perspective.

Pseudoscalar Mesons and Emergent Mass

Despite its role in the continuing evolution of the Universe, only a small fraction of the mass of visible material can be attributed to the Higgs boson alone. The overwhelmingly dominant share may/should arise from the strong interactions that act in the heart of nuclear matter; namely, those described by quantum chromodynamics. This contribution describes how studying and explaining the attributes of pseudoscalar mesons can open an insightful window onto understanding the origin of mass in the Standard Model and how these insights inform our knowledge of hadron structure. The survey ranges over distribution amplitudes and functions, electromagnetic and gravitational form factors, light-front wave functions, and generalized parton distributions. Advances made using continuum Schwinger function methods and their relevance for experimental efforts are highlighted.

Star formation across cosmic time

The interstellar medium of galaxies is composed of multiple phases, including molecular, atomic, and ionized gas, as well as dust. Stars are formed within this medium from cold molecular gas clouds, which collapse due to their gravitational attraction. Throughout their life, stars emit strong radiation fields and stellar winds, and they can also explode as supernovae at the end of their life. These processes contribute to stirring the turbulent interstellar medium and regulate star formation by heating up, ionizing, and expelling part of the gas. However, star formation does not proceed uniformly throughout the history of the Universe and decrease by an order of magnitude in the last ten billion years. To understand this winding-down of star formation and assess possible variations in the efficiency of star formation, it is crucial to probe the molecular gas reservoirs from which stars are formed. In this article following my presentation at the 10th International Conference on Frontiers of Plasma Physics and Technology held in Kathmandu from 13–17 March 2023, I review some aspects of the multiphase interstellar medium and star formation, with an emphasis on the interplay between neutral and ionized phases, and present recent and ongoing observations of the molecular gas content in typical star-forming galaxies across cosmic time and in different environments. I also present some of our understanding of star-forming galaxies from theoretical models and simulations.

A unified model of particle physics and cosmology: Origin of inflation, baryogenesis, neutrino mass, CDM and dark energy

I propose a unified model of particle physic and cosmology based on both a new extension of the standard particle model and the fundamental principle of the standard cosmology. Beyond the standard model, I introduce several species of dark fields with the dark symmetry of [Formula: see text], the inflation field, cold dark matter (CDM) and dark energy (DE) are of course included among them. The model can coherently and completely describe the origin and evolution of the universe from the primordial inflation to the reheating, to the baryogenesis, to the current CDM and DE, and also the neutrino mass generation mechanism. For the energy evolution of each phase, I give its dynamical system of equations, and solve them by some special techniques. The numerical results can clearly show how each evolution is successfully implemented, furthermore, the model demonstrates that the DE genesis is purely from the CDM condensation, which is essentially a reverse process of the primordial slow-roll inflation, there is not the so-called “cosmological constant energy”. By use of fewer input parameters, the model not only exactly reproduces the measured inflationary data and the current energy density budget, but also finely predicts such important values as the tensor-to-scalar ratio [Formula: see text], the inflaton mass [Formula: see text][Formula: see text]GeV, the reheating temperature [Formula: see text][Formula: see text]GeV, the CDM mass [Formula: see text][Formula: see text]GeV, [Formula: see text] and [Formula: see text], in particular, the model smoothly clarifies and eliminates the “Hubble tension”. In short, the unified model newly establishes the deeper and closer relations between particle physics and cosmology, therefore we expect the ongoing and future experiments to test the model.

Expansion of the universe on fractal time: A study on the dynamics of cosmic growth

In this paper, fractal space–time, the Hubble horizon and the energy–momentum tensor are examined in relation to the FLRW metric. It offers a Fractal Friedman equation along with its answer. Also included is the scale factor, which includes fractal structures for closed, flat and open universes. They offer fresh insights into the behavior and evolution of the universe through detailed plots that vividly illustrate their potential cosmological implications.

Probing the universe's expansion dynamics: The linear correction scenario perspective on dark energy

In this study, we investigate the cosmological evolution of the universe, focusing on the KMMS models in a model-independent approach, particularly the scenario involving linear correction, given by E2(z)=A(z)+β(1+γB(z)), where A(z)=Ωm0(1+z)3 and B(z)=z. By analyzing recent Cosmic Chronometers (CC) and the Pantheon+ samples, we determine the best-fit values of model parameters using a Markov chain Monte Carlo analysis. Our models exhibit unique dynamics, transitioning from super-exponential to exponential expansion, with a significant shift at redshift zt=0.83−0.10+0.11 and present deceleration parameter q0=−0.69−0.17+0.17. The jerk parameter exceeds 1, indicating a faster change in acceleration than predicted by ΛCDM. The energy density parameter is consistent with Planck observations, and the dark sector evolution follows the expected thermal history. The EoS parameter approaches ωde=−1 over time, with a current value of ωde0=−1.06±0.12, aligning with the phantom phase. Our model presents a new dark energy alternative, emphasizing the importance of considering models like KMMS in understanding cosmic evolution.

Mythological Number Seven In Turkmen Culture

Numbers are the symbolic codes of mythology. They carry the mysteries of archaic beliefs and traditional life from past to present. Seven appears in all works of folk literature. The number seven is one of these special numbers. There is information about seven in all societies, beliefs and cultures around the world. People make use of the number seven to explain the creation of the universe, the sky, heaven and hell, etc. Seven is the number of nursery rhymes. Many societies do not perform important rituals without repeating them seven times. Among Turkic peoples, seven is very important for Turkmens. In Turkmen mythology, seven is very special. It stands out more than numbers like three, five, nine and forty. Seven is present in all traditions from birth to death. In child rituals, marriage and death, the number seven is present as a formula. With this formula, the message is emphasized. People understand situations, behaviors and names better with seven repetitions. Seven is found as a stylistic number in fairy tales, epics and legends. In Turkmen society, there are even sevens explaining positive and negative situations and behaviors. These sevens bear the traces of mythology and cultural identity. Many Turkmen rituals are not complete without being performed seven times. This article first provides general information about the number seven. Then examples of seven in Turkmen culture, folk literature and beliefs are given. In these sevens, family, lineage, badly behaved women, and traditions of entertaining good guests are included. Finally, examples of the number seven, which has mythological roots in Turkmen culture, are evaluated. It is stated that they are soci­ological, religious and cultural codes.

Cosmological transition epoch from gamma-ray burst correlations

The redshift zt and the jerk parameter jt of the transition epoch are constrained by using two model-independent approaches involving the direct expansion of the Hubble rate and the expansion of the deceleration parameter around z=zt. To extend our analysis to high-redshifts, we employ the Amati, Combo, Yonetoku and Dainotti gamma-ray burst correlations. The circularity problem is prevented by calibrating these correlations through the Bézier interpolation of the updated observational Hubble data. Each gamma-ray burst data set is jointly fit with type Ia supernovae and baryonic acoustic oscillations through a Monte Carlo analysis, based on the Metropolis-Hastings algorithm, to obtain zt, jt and the correlation parameters. The overall results are compatible with the concordance model with some exceptions. We also focus on the behaviors of the dark energy, verifying its compatibility with a cosmological constant, and the matter density Ωm and compare them with the expectations of the concordance paradigm.

Can nonlocal gravity really explain dark energy?

In view to scrutinize the idea that nonlocal modifications of General Relativity could dynamically address the dark energy problem, we investigate the evolution of the Universe at infrared scales as an Infinite Derivative Gravity model of the Ricci scalar, without introducing the cosmological constant Λ or any scalar field. The accelerated expansion of the late Universe is shown to be compatible with the emergence of nonlocal gravitational effects at sufficiently low energies. A technique for circumventing the mathematical complexity of the nonlocal cosmological equations is developed and, after drawing a connection with the Starobinsky gravity, verifiable predictions are considered, like a possible decreasing in the strength of the effective gravitational constant. In conclusion, the emergence of nonlocal gravity corrections at given scales could be an efficient mechanism to address the dark energy problem.